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2025-10-29tcp: add newval parameter to tcp_rcvbuf_grow()Eric Dumazet1-1/+1
This patch has no functional change, and prepares the following one. tcp_rcvbuf_grow() will need to have access to tp->rcvq_space.space old and new values. Change mptcp_rcvbuf_grow() in a similar way. Signed-off-by: Eric Dumazet <edumazet@google.com> [ Moved 'oldval' declaration to the next patch to avoid warnings at build time. ] Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Reviewed-by: Neal Cardwell <ncardwell@google.com> Link: https://patch.msgid.link/20251028-net-tcp-recv-autotune-v3-3-74b43ba4c84c@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-29tcp: make tcp_rcvbuf_grow() accessible to mptcp codePaolo Abeni1-0/+1
To leverage the auto-tuning improvements brought by commit 2da35e4b4df9 ("Merge branch 'tcp-receive-side-improvements'"), the MPTCP stack need to access the mentioned helper. Acked-by: Geliang Tang <geliang@kernel.org> Acked-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250927-net-next-mptcp-rcv-path-imp-v1-2-5da266aa9c1a@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-18tcp: accecn: AccECN option ceb/cep and ACE field multi-wrap heuristicsIlpo Järvinen1-0/+1
The AccECN option ceb/cep heuristic algorithm is from AccECN spec Appendix A.2.2 to mitigate against false ACE field overflows. Armed with ceb delta from option, delivered bytes, and delivered packets it is possible to estimate how many times ACE field wrapped. This calculation is necessary only if more than one wrap is possible. Without SACK, delivered bytes and packets are not always trustworthy in which case TCP falls back to the simpler no-or-all wraps ceb algorithm. Signed-off-by: Ilpo Järvinen <ij@kernel.org> Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250916082434.100722-10-chia-yu.chang@nokia-bell-labs.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-09-18tcp: accecn: AccECN option send controlChia-Yu Chang1-0/+3
Instead of sending the option in every ACK, limit sending to those ACKs where the option is necessary: - Handshake - "Change-triggered ACK" + the ACK following it. The 2nd ACK is necessary to unambiguously indicate which of the ECN byte counters in increasing. The first ACK has two counters increasing due to the ecnfield edge. - ACKs with CE to allow CEP delta validations to take advantage of the option. - Force option to be sent every at least once per 2^22 bytes. The check is done using the bit edges of the byte counters (avoids need for extra variables). - AccECN option beacon to send a few times per RTT even if nothing in the ECN state requires that. The default is 3 times per RTT, and its period can be set via sysctl_tcp_ecn_option_beacon. Below are the pahole outcomes before and after this patch, in which the group size of tcp_sock_write_tx is increased from 89 to 97 due to the new u64 accecn_opt_tstamp member: [BEFORE THIS PATCH] struct tcp_sock { [...] u64 tcp_wstamp_ns; /* 2488 8 */ struct list_head tsorted_sent_queue; /* 2496 16 */ [...] __cacheline_group_end__tcp_sock_write_tx[0]; /* 2521 0 */ __cacheline_group_begin__tcp_sock_write_txrx[0]; /* 2521 0 */ u8 nonagle:4; /* 2521: 0 1 */ u8 rate_app_limited:1; /* 2521: 4 1 */ /* XXX 3 bits hole, try to pack */ /* Force alignment to the next boundary: */ u8 :0; u8 received_ce_pending:4;/* 2522: 0 1 */ u8 unused2:4; /* 2522: 4 1 */ u8 accecn_minlen:2; /* 2523: 0 1 */ u8 est_ecnfield:2; /* 2523: 2 1 */ u8 unused3:4; /* 2523: 4 1 */ [...] __cacheline_group_end__tcp_sock_write_txrx[0]; /* 2628 0 */ [...] /* size: 3200, cachelines: 50, members: 171 */ } [AFTER THIS PATCH] struct tcp_sock { [...] u64 tcp_wstamp_ns; /* 2488 8 */ u64 accecn_opt_tstamp; /* 2596 8 */ struct list_head tsorted_sent_queue; /* 2504 16 */ [...] __cacheline_group_end__tcp_sock_write_tx[0]; /* 2529 0 */ __cacheline_group_begin__tcp_sock_write_txrx[0]; /* 2529 0 */ u8 nonagle:4; /* 2529: 0 1 */ u8 rate_app_limited:1; /* 2529: 4 1 */ /* XXX 3 bits hole, try to pack */ /* Force alignment to the next boundary: */ u8 :0; u8 received_ce_pending:4;/* 2530: 0 1 */ u8 unused2:4; /* 2530: 4 1 */ u8 accecn_minlen:2; /* 2531: 0 1 */ u8 est_ecnfield:2; /* 2531: 2 1 */ u8 accecn_opt_demand:2; /* 2531: 4 1 */ u8 prev_ecnfield:2; /* 2531: 6 1 */ [...] __cacheline_group_end__tcp_sock_write_txrx[0]; /* 2636 0 */ [...] /* size: 3200, cachelines: 50, members: 173 */ } Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Co-developed-by: Ilpo Järvinen <ij@kernel.org> Signed-off-by: Ilpo Järvinen <ij@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250916082434.100722-8-chia-yu.chang@nokia-bell-labs.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-09-18tcp: accecn: AccECN optionIlpo Järvinen1-0/+13
The Accurate ECN allows echoing back the sum of bytes for each IP ECN field value in the received packets using AccECN option. This change implements AccECN option tx & rx side processing without option send control related features that are added by a later change. Based on specification: https://tools.ietf.org/id/draft-ietf-tcpm-accurate-ecn-28.txt (Some features of the spec will be added in the later changes rather than in this one). A full-length AccECN option is always attempted but if it does not fit, the minimum length is selected based on the counters that have changed since the last update. The AccECN option (with 24-bit fields) often ends in odd sizes so the option write code tries to take advantage of some nop used to pad the other TCP options. The delivered_ecn_bytes pairs with received_ecn_bytes similar to how delivered_ce pairs with received_ce. In contrast to ACE field, however, the option is not always available to update delivered_ecn_bytes. For ACK w/o AccECN option, the delivered bytes calculated based on the cumulative ACK+SACK information are assigned to one of the counters using an estimation heuristic to select the most likely ECN byte counter. Any estimation error is corrected when the next AccECN option arrives. It may occur that the heuristic gets too confused when there are enough different byte counter deltas between ACKs with the AccECN option in which case the heuristic just gives up on updating the counters for a while. tcp_ecn_option sysctl can be used to select option sending mode for AccECN: TCP_ECN_OPTION_DISABLED, TCP_ECN_OPTION_MINIMUM, and TCP_ECN_OPTION_FULL. This patch increases the size of tcp_info struct, as there is no existing holes for new u32 variables. Below are the pahole outcomes before and after this patch: [BEFORE THIS PATCH] struct tcp_info { [...] __u32 tcpi_total_rto_time; /* 244 4 */ /* size: 248, cachelines: 4, members: 61 */ } [AFTER THIS PATCH] struct tcp_info { [...] __u32 tcpi_total_rto_time; /* 244 4 */ __u32 tcpi_received_ce; /* 248 4 */ __u32 tcpi_delivered_e1_bytes; /* 252 4 */ __u32 tcpi_delivered_e0_bytes; /* 256 4 */ __u32 tcpi_delivered_ce_bytes; /* 260 4 */ __u32 tcpi_received_e1_bytes; /* 264 4 */ __u32 tcpi_received_e0_bytes; /* 268 4 */ __u32 tcpi_received_ce_bytes; /* 272 4 */ /* size: 280, cachelines: 5, members: 68 */ } This patch uses the existing 1-byte holes in the tcp_sock_write_txrx group for new u8 members, but adds a 4-byte hole in tcp_sock_write_rx group after the new u32 delivered_ecn_bytes[3] member. Therefore, the group size of tcp_sock_write_rx is increased from 96 to 112. Below are the pahole outcomes before and after this patch: [BEFORE THIS PATCH] struct tcp_sock { [...] u8 received_ce_pending:4; /* 2522: 0 1 */ u8 unused2:4; /* 2522: 4 1 */ /* XXX 1 byte hole, try to pack */ [...] u32 rcv_rtt_last_tsecr; /* 2668 4 */ [...] __cacheline_group_end__tcp_sock_write_rx[0]; /* 2728 0 */ [...] /* size: 3200, cachelines: 50, members: 167 */ } [AFTER THIS PATCH] struct tcp_sock { [...] u8 received_ce_pending:4;/* 2522: 0 1 */ u8 unused2:4; /* 2522: 4 1 */ u8 accecn_minlen:2; /* 2523: 0 1 */ u8 est_ecnfield:2; /* 2523: 2 1 */ u8 unused3:4; /* 2523: 4 1 */ [...] u32 rcv_rtt_last_tsecr; /* 2668 4 */ u32 delivered_ecn_bytes[3];/* 2672 12 */ /* XXX 4 bytes hole, try to pack */ [...] __cacheline_group_end__tcp_sock_write_rx[0]; /* 2744 0 */ [...] /* size: 3200, cachelines: 50, members: 171 */ } Signed-off-by: Ilpo Järvinen <ij@kernel.org> Signed-off-by: Neal Cardwell <ncardwell@google.com> Co-developed-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250916082434.100722-7-chia-yu.chang@nokia-bell-labs.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-09-18tcp: accecn: AccECN negotiationIlpo Järvinen1-0/+1
Accurate ECN negotiation parts based on the specification: https://tools.ietf.org/id/draft-ietf-tcpm-accurate-ecn-28.txt Accurate ECN is negotiated using ECE, CWR and AE flags in the TCP header. TCP falls back into using RFC3168 ECN if one of the ends supports only RFC3168-style ECN. The AccECN negotiation includes reflecting IP ECN field value seen in SYN and SYNACK back using the same bits as negotiation to allow responding to SYN CE marks and to detect ECN field mangling. CE marks should not occur currently because SYN=1 segments are sent with Non-ECT in IP ECN field (but proposal exists to remove this restriction). Reflecting SYN IP ECN field in SYNACK is relatively simple. Reflecting SYNACK IP ECN field in the final/third ACK of the handshake is more challenging. Linux TCP code is not well prepared for using the final/third ACK a signalling channel which makes things somewhat complicated here. tcp_ecn sysctl can be used to select the highest ECN variant (Accurate ECN, ECN, No ECN) that is attemped to be negotiated and requested for incoming connection and outgoing connection: TCP_ECN_IN_NOECN_OUT_NOECN, TCP_ECN_IN_ECN_OUT_ECN, TCP_ECN_IN_ECN_OUT_NOECN, TCP_ECN_IN_ACCECN_OUT_ACCECN, TCP_ECN_IN_ACCECN_OUT_ECN, and TCP_ECN_IN_ACCECN_OUT_NOECN. After this patch, the size of tcp_request_sock remains unchanged and no new holes are added. Below are the pahole outcomes before and after this patch: [BEFORE THIS PATCH] struct tcp_request_sock { [...] u32 rcv_nxt; /* 352 4 */ u8 syn_tos; /* 356 1 */ /* size: 360, cachelines: 6, members: 16 */ } [AFTER THIS PATCH] struct tcp_request_sock { [...] u32 rcv_nxt; /* 352 4 */ u8 syn_tos; /* 356 1 */ bool accecn_ok; /* 357 1 */ u8 syn_ect_snt:2; /* 358: 0 1 */ u8 syn_ect_rcv:2; /* 358: 2 1 */ u8 accecn_fail_mode:4; /* 358: 4 1 */ /* size: 360, cachelines: 6, members: 20 */ } After this patch, the size of tcp_sock remains unchanged and no new holes are added. Also, 4 bits of the existing 2-byte hole are exploited. Below are the pahole outcomes before and after this patch: [BEFORE THIS PATCH] struct tcp_sock { [...] u8 dup_ack_counter:2; /* 2761: 0 1 */ u8 tlp_retrans:1; /* 2761: 2 1 */ u8 unused:5; /* 2761: 3 1 */ u8 thin_lto:1; /* 2762: 0 1 */ u8 fastopen_connect:1; /* 2762: 1 1 */ u8 fastopen_no_cookie:1; /* 2762: 2 1 */ u8 fastopen_client_fail:2; /* 2762: 3 1 */ u8 frto:1; /* 2762: 5 1 */ /* XXX 2 bits hole, try to pack */ [...] u8 keepalive_probes; /* 2765 1 */ /* XXX 2 bytes hole, try to pack */ [...] /* size: 3200, cachelines: 50, members: 164 */ } [AFTER THIS PATCH] struct tcp_sock { [...] u8 dup_ack_counter:2; /* 2761: 0 1 */ u8 tlp_retrans:1; /* 2761: 2 1 */ u8 syn_ect_snt:2; /* 2761: 3 1 */ u8 syn_ect_rcv:2; /* 2761: 5 1 */ u8 thin_lto:1; /* 2761: 7 1 */ u8 fastopen_connect:1; /* 2762: 0 1 */ u8 fastopen_no_cookie:1; /* 2762: 1 1 */ u8 fastopen_client_fail:2; /* 2762: 2 1 */ u8 frto:1; /* 2762: 4 1 */ /* XXX 3 bits hole, try to pack */ [...] u8 keepalive_probes; /* 2765 1 */ u8 accecn_fail_mode:4; /* 2766: 0 1 */ /* XXX 4 bits hole, try to pack */ /* XXX 1 byte hole, try to pack */ [...] /* size: 3200, cachelines: 50, members: 166 */ } Signed-off-by: Ilpo Järvinen <ij@kernel.org> Co-developed-by: Olivier Tilmans <olivier.tilmans@nokia.com> Signed-off-by: Olivier Tilmans <olivier.tilmans@nokia.com> Co-developed-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250916082434.100722-3-chia-yu.chang@nokia-bell-labs.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-09-18tcp: AccECN coreIlpo Järvinen1-0/+15
This change implements Accurate ECN without negotiation and AccECN Option (that will be added by later changes). Based on AccECN specifications: https://tools.ietf.org/id/draft-ietf-tcpm-accurate-ecn-28.txt Accurate ECN allows feeding back the number of CE (congestion experienced) marks accurately to the sender in contrast to RFC3168 ECN that can only signal one marks-seen-yes/no per RTT. Congestion control algorithms can take advantage of the accurate ECN information to fine-tune their congestion response to avoid drastic rate reduction when only mild congestion is encountered. With Accurate ECN, tp->received_ce (r.cep in AccECN spec) keeps track of how many segments have arrived with a CE mark. Accurate ECN uses ACE field (ECE, CWR, AE) to communicate the value back to the sender which updates tp->delivered_ce (s.cep) based on the feedback. This signalling channel is lossy when ACE field overflow occurs. Conservative strategy is selected here to deal with the ACE overflow, however, some strategies using the AccECN option later in the overall patchset mitigate against false overflows detected. The ACE field values on the wire are offset by TCP_ACCECN_CEP_INIT_OFFSET. Delivered_ce/received_ce count the real CE marks rather than forcing all downstream users to adapt to the wire offset. This patch uses the first 1-byte hole and the last 4-byte hole of the tcp_sock_write_txrx for 'received_ce_pending' and 'received_ce'. Also, the group size of tcp_sock_write_txrx is increased from 91 + 4 to 95 + 4 due to the new u32 received_ce member. Below are the trimmed pahole outcomes before and after this patch. [BEFORE THIS PATCH] struct tcp_sock { [...] __cacheline_group_begin__tcp_sock_write_txrx[0]; /* 2521 0 */ u8 nonagle:4; /* 2521: 0 1 */ u8 rate_app_limited:1; /* 2521: 4 1 */ /* XXX 3 bits hole, try to pack */ /* XXX 2 bytes hole, try to pack */ [...] u32 delivered_ce; /* 2576 4 */ u32 app_limited; /* 2580 4 */ u32 rcv_wnd; /* 2684 4 */ struct tcp_options_received rx_opt; /* 2688 24 */ __cacheline_group_end__tcp_sock_write_txrx[0]; /* 2612 0 */ /* XXX 4 bytes hole, try to pack */ [...] /* size: 3200, cachelines: 50, members: 161 */ } [AFTER THIS PATCH] struct tcp_sock { [...] __cacheline_group_begin__tcp_sock_write_txrx[0]; /* 2521 0 */ u8 nonagle:4; /* 2521: 0 1 */ u8 rate_app_limited:1; /* 2521: 4 1 */ /* XXX 3 bits hole, try to pack */ /* Force alignment to the next boundary: */ u8 :0; u8 received_ce_pending:4;/* 2522: 0 1 */ u8 unused2:4; /* 2522: 4 1 */ /* XXX 1 byte hole, try to pack */ [...] u32 delivered_ce; /* 2576 4 */ u32 received_ce; /* 2580 4 */ u32 app_limited; /* 2584 4 */ u32 rcv_wnd; /* 2588 4 */ struct tcp_options_received rx_opt; /* 2592 24 */ __cacheline_group_end__tcp_sock_write_txrx[0]; /* 2616 0 */ [...] /* size: 3200, cachelines: 50, members: 164 */ } Signed-off-by: Ilpo Järvinen <ij@kernel.org> Co-developed-by: Olivier Tilmans <olivier.tilmans@nokia.com> Signed-off-by: Olivier Tilmans <olivier.tilmans@nokia.com> Co-developed-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250916082434.100722-2-chia-yu.chang@nokia-bell-labs.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-09-15tcp: fast path functions laterIlpo Järvinen1-27/+27
The following patch will use tcp_ecn_mode_accecn(), TCP_ACCECN_CEP_INIT_OFFSET, TCP_ACCECN_CEP_ACE_MASK in __tcp_fast_path_on() to make new flag for AccECN. No functional changes. Signed-off-by: Ilpo Järvinen <ij@kernel.org> Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250911110642.87529-3-chia-yu.chang@nokia-bell-labs.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-11tcp: Destroy TCP-AO, TCP-MD5 keys in .sk_destruct()Dmitry Safonov1-0/+4
Currently there are a couple of minor issues with destroying the keys tcp_v4_destroy_sock(): 1. The socket is yet in TCP bind buckets, making it reachable for incoming segments [on another CPU core], potentially available to send late FIN/ACK/RST replies. 2. There is at least one code path, where tcp_done() is called before sending RST [kudos to Bob for investigation]. This is a case of a server, that finished sending its data and just called close(). The socket is in TCP_FIN_WAIT2 and has RCV_SHUTDOWN (set by __tcp_close()) tcp_v4_do_rcv()/tcp_v6_do_rcv() tcp_rcv_state_process() /* LINUX_MIB_TCPABORTONDATA */ tcp_reset() tcp_done_with_error() tcp_done() inet_csk_destroy_sock() /* Destroys AO/MD5 keys */ /* tcp_rcv_state_process() returns SKB_DROP_REASON_TCP_ABORT_ON_DATA */ tcp_v4_send_reset() /* Sends an unsigned RST segment */ tcpdump: > 22:53:15.399377 00:00:b2:1f:00:00 > 00:00:01:01:00:00, ethertype IPv4 (0x0800), length 74: (tos 0x0, ttl 64, id 33929, offset 0, flags [DF], proto TCP (6), length 60) > 1.0.0.1.34567 > 1.0.0.2.49848: Flags [F.], seq 2185658590, ack 3969644355, win 502, options [nop,nop,md5 valid], length 0 > 22:53:15.399396 00:00:01:01:00:00 > 00:00:b2:1f:00:00, ethertype IPv4 (0x0800), length 86: (tos 0x0, ttl 64, id 51951, offset 0, flags [DF], proto TCP (6), length 72) > 1.0.0.2.49848 > 1.0.0.1.34567: Flags [.], seq 3969644375, ack 2185658591, win 128, options [nop,nop,md5 valid,nop,nop,sack 1 {2185658590:2185658591}], length 0 > 22:53:16.429588 00:00:b2:1f:00:00 > 00:00:01:01:00:00, ethertype IPv4 (0x0800), length 60: (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 40) > 1.0.0.1.34567 > 1.0.0.2.49848: Flags [R], seq 2185658590, win 0, length 0 > 22:53:16.664725 00:00:b2:1f:00:00 > 00:00:01:01:00:00, ethertype IPv4 (0x0800), length 74: (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 60) > 1.0.0.1.34567 > 1.0.0.2.49848: Flags [R], seq 2185658591, win 0, options [nop,nop,md5 valid], length 0 > 22:53:17.289832 00:00:b2:1f:00:00 > 00:00:01:01:00:00, ethertype IPv4 (0x0800), length 74: (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 60) > 1.0.0.1.34567 > 1.0.0.2.49848: Flags [R], seq 2185658591, win 0, options [nop,nop,md5 valid], length 0 Note the signed RSTs later in the dump - those are sent by the server when the fin-wait socket gets removed from hash buckets, by the listener socket. Instead of destroying AO/MD5 info and their keys in inet_csk_destroy_sock(), slightly delay it until the actual socket .sk_destruct(). As shutdown'ed socket can yet send non-data replies, they should be signed in order for the peer to process them. Now it also matches how AO/MD5 gets destructed for TIME-WAIT sockets (in tcp_twsk_destructor()). This seems optimal for TCP-MD5, while for TCP-AO it seems to have an open problem: once RST get sent and socket gets actually destructed, there is no information on the initial sequence numbers. So, in case this last RST gets lost in the network, the server's listener socket won't be able to properly sign another RST. Nothing in RFC 1122 prescribes keeping any local state after non-graceful reset. Luckily, BGP are known to use keep alive(s). While the issue is quite minor/cosmetic, these days monitoring network counters is a common practice and getting invalid signed segments from a trusted BGP peer can get customers worried. Investigated-by: Bob Gilligan <gilligan@arista.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Signed-off-by: Dmitry Safonov <dima@arista.com> Link: https://patch.msgid.link/20250909-b4-tcp-ao-md5-rst-finwait2-v5-1-9ffaaaf8b236@arista.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-01tcp: Remove sk->sk_prot->orphan_count.Kuniyuki Iwashima1-0/+10
TCP tracks the number of orphaned (SOCK_DEAD but not yet destructed) sockets in tcp_orphan_count. In some code that was shared with DCCP, tcp_orphan_count is referenced via sk->sk_prot->orphan_count. Let's reference tcp_orphan_count directly. inet_csk_prepare_for_destroy_sock() is moved to inet_connection_sock.c due to header dependency. Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250829215641.711664-1-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-08-28net: add sk_drops_read(), sk_drops_inc() and sk_drops_reset() helpersEric Dumazet1-1/+1
We want to split sk->sk_drops in the future to reduce potential contention on this field. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20250826125031.1578842-2-edumazet@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-08-19net-memcg: Pass struct sock to mem_cgroup_sk_under_memory_pressure().Kuniyuki Iwashima1-1/+1
We will store a flag in the lowest bit of sk->sk_memcg. Then, we cannot pass the raw pointer to mem_cgroup_under_socket_pressure(). Let's pass struct sock to it and rename the function to match other functions starting with mem_cgroup_sk_. Note that the helper is moved to sock.h to use mem_cgroup_from_sk(). Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: Roman Gushchin <roman.gushchin@linux.dev> Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Link: https://patch.msgid.link/20250815201712.1745332-10-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-08-19net-memcg: Introduce mem_cgroup_sk_enabled().Kuniyuki Iwashima1-1/+1
The socket memcg feature is enabled by a static key and only works for non-root cgroup. We check both conditions in many places. Let's factorise it as a helper function. Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: Roman Gushchin <roman.gushchin@linux.dev> Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Link: https://patch.msgid.link/20250815201712.1745332-8-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-08-06Merge tag 'kbuild-v6.17-2' of ↵Linus Torvalds1-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: "This is the last pull request from me. I'm grateful to have been able to continue as a maintainer for eight years. From the next cycle, Nathan and Nicolas will maintain Kbuild. - Fix a shortcut key issue in menuconfig - Fix missing rebuild of kheaders - Sort the symbol dump generated by gendwarfsyms - Support zboot extraction in scripts/extract-vmlinux - Migrate gconfig to GTK 3 - Add TAR variable to allow overriding the default tar command - Hand over Kbuild maintainership" * tag 'kbuild-v6.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (92 commits) MAINTAINERS: hand over Kbuild maintenance kheaders: make it possible to override TAR kbuild: userprogs: use correct linker when mixing clang and GNU ld kconfig: lxdialog: replace strcpy() with strncpy() in inputbox.c kconfig: lxdialog: replace strcpy with snprintf in print_autowrap kconfig: gconf: refactor text_insert_help() kconfig: gconf: remove unneeded variable in text_insert_msg kconfig: gconf: use hyphens in signals kconfig: gconf: replace GtkImageMenuItem with GtkMenuItem kconfig: gconf: Fix Back button behavior kconfig: gconf: fix single view to display dependent symbols correctly scripts: add zboot support to extract-vmlinux gendwarfksyms: order -T symtypes output by name gendwarfksyms: use preferred form of sizeof for allocation kconfig: qconf: confine {begin,end}Group to constructor and destructor kconfig: qconf: fix ConfigList::updateListAllforAll() kconfig: add a function to dump all menu entries in a tree-like format kconfig: gconf: show GTK version in About dialog kconfig: gconf: replace GtkHPaned and GtkVPaned with GtkPaned kconfig: gconf: replace GdkColor with GdkRGBA ...
2025-07-18net: track pfmemalloc drops via SKB_DROP_REASON_PFMEMALLOCJesper Dangaard Brouer1-1/+1
Add a new SKB drop reason (SKB_DROP_REASON_PFMEMALLOC) to track packets dropped due to memory pressure. In production environments, we've observed memory exhaustion reported by memory layer stack traces, but these drops were not properly tracked in the SKB drop reason infrastructure. While most network code paths now properly report pfmemalloc drops, some protocol-specific socket implementations still use sk_filter() without drop reason tracking: - Bluetooth L2CAP sockets - CAIF sockets - IUCV sockets - Netlink sockets - SCTP sockets - Unix domain sockets These remaining cases represent less common paths and could be converted in a follow-up patch if needed. The current implementation provides significantly improved observability into memory pressure events in the network stack, especially for key protocols like TCP and UDP, helping to diagnose problems in production environments. Reported-by: Matt Fleming <mfleming@cloudflare.com> Signed-off-by: Jesper Dangaard Brouer <hawk@kernel.org> Link: https://patch.msgid.link/175268316579.2407873.11634752355644843509.stgit@firesoul Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-07-02tcp: move tcp_memory_allocated into net_aligned_dataEric Dumazet1-1/+0
____cacheline_aligned_in_smp attribute only makes sure to align a field to a cache line. It does not prevent the linker to use the remaining of the cache line for other variables, causing potential false sharing. Move tcp_memory_allocated into a dedicated cache line. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20250630093540.3052835-4-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-06-24module: remove meaningless 'name' parameter from __MODULE_INFO()Masahiro Yamada1-2/+2
The symbol names in the .modinfo section are never used and already randomized by the __UNIQUE_ID() macro. Therefore, the second parameter of __MODULE_INFO() is meaningless and can be removed to simplify the code. With this change, the symbol names in the .modinfo section will be prefixed with __UNIQUE_ID_modinfo, making it clearer that they originate from MODULE_INFO(). [Before] $ objcopy -j .modinfo vmlinux.o modinfo.o $ nm -n modinfo.o | head -n10 0000000000000000 r __UNIQUE_ID_license560 0000000000000011 r __UNIQUE_ID_file559 0000000000000030 r __UNIQUE_ID_description558 0000000000000074 r __UNIQUE_ID_license580 000000000000008e r __UNIQUE_ID_file579 00000000000000bd r __UNIQUE_ID_description578 00000000000000e6 r __UNIQUE_ID_license581 00000000000000ff r __UNIQUE_ID_file580 0000000000000134 r __UNIQUE_ID_description579 0000000000000179 r __UNIQUE_ID_uncore_no_discover578 [After] $ objcopy -j .modinfo vmlinux.o modinfo.o $ nm -n modinfo.o | head -n10 0000000000000000 r __UNIQUE_ID_modinfo560 0000000000000011 r __UNIQUE_ID_modinfo559 0000000000000030 r __UNIQUE_ID_modinfo558 0000000000000074 r __UNIQUE_ID_modinfo580 000000000000008e r __UNIQUE_ID_modinfo579 00000000000000bd r __UNIQUE_ID_modinfo578 00000000000000e6 r __UNIQUE_ID_modinfo581 00000000000000ff r __UNIQUE_ID_modinfo580 0000000000000134 r __UNIQUE_ID_modinfo579 0000000000000179 r __UNIQUE_ID_modinfo578 Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Petr Pavlu <petr.pavlu@suse.com>
2025-06-17net: tcp: tsq: Convert from tasklet to BH workqueueTejun Heo1-1/+1
The only generic interface to execute asynchronously in the BH context is tasklet; however, it's marked deprecated and has some design flaws. To replace tasklets, BH workqueue support was recently added. A BH workqueue behaves similarly to regular workqueues except that the queued work items are executed in the BH context. This patch converts TCP Small Queues implementation from tasklet to BH workqueue. Semantically, this is an equivalent conversion and there shouldn't be any user-visible behavior changes. While workqueue's queueing and execution paths are a bit heavier than tasklet's, unless the work item is being queued every packet, the difference hopefully shouldn't matter. My experience with the networking stack is very limited and this patch definitely needs attention from someone who actually understands networking. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Cc: David Ahern <dsahern@kernel.org> Link: https://patch.msgid.link/aFBeJ38AS1ZF3Dq5@slm.duckdns.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-06-17tcp: remove RFC3517/RFC6675 tcp_clear_retrans_hints_partial()Neal Cardwell1-5/+0
Now that we have removed the RFC3517/RFC6675 hints, tcp_clear_retrans_hints_partial() is empty, and can be removed. Suggested-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Yuchung Cheng <ycheng@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250615001435.2390793-4-ncardwell.sw@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-06-17tcp: remove RFC3517/RFC6675 hint state: lost_skb_hint, lost_cnt_hintNeal Cardwell1-1/+0
Now that obsolete RFC3517/RFC6675 TCP loss detection has been removed, we can remove the somewhat complex and intrusive code to maintain its hint state: lost_skb_hint and lost_cnt_hint. This commit makes tcp_clear_retrans_hints_partial() empty. We will remove tcp_clear_retrans_hints_partial() and its call sites in the next commit. Suggested-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Yuchung Cheng <ycheng@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250615001435.2390793-3-ncardwell.sw@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-10tcp: add TCP_RFC7323_TW_PAWS drop reasonJiayuan Chen1-1/+2
Devices in the networking path, such as firewalls, NATs, or routers, which can perform SNAT or DNAT, use addresses from their own limited address pools to masquerade the source address during forwarding, causing PAWS verification to fail more easily. Currently, packet loss statistics for PAWS can only be viewed through MIB, which is a global metric and cannot be precisely obtained through tracing to get the specific 4-tuple of the dropped packet. In the past, we had to use kprobe ret to retrieve relevant skb information from tcp_timewait_state_process(). We add a drop_reason pointer, similar to what previous commit does: commit e34100c2ecbb ("tcp: add a drop_reason pointer to tcp_check_req()") This commit addresses the PAWSESTABREJECTED case and also sets the corresponding drop reason. We use 'pwru' to test. Before this commit: '''' ./pwru 'port 9999' 2025/04/07 13:40:19 Listening for events.. TUPLE FUNC 172.31.75.115:12345->172.31.75.114:9999(tcp) sk_skb_reason_drop(SKB_DROP_REASON_NOT_SPECIFIED) ''' After this commit: ''' ./pwru 'port 9999' 2025/04/07 13:51:34 Listening for events.. TUPLE FUNC 172.31.75.115:12345->172.31.75.114:9999(tcp) sk_skb_reason_drop(SKB_DROP_REASON_TCP_RFC7323_TW_PAWS) ''' Suggested-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250409112614.16153-2-jiayuan.chen@linux.dev Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-31Revert "tcp: avoid atomic operations on sk->sk_rmem_alloc"Eric Dumazet1-15/+0
This reverts commit 0de2a5c4b824da2205658ebebb99a55c43cdf60f. I forgot that a TCP socket could receive messages in its error queue. sock_queue_err_skb() can be called without socket lock being held, and changes sk->sk_rmem_alloc. The fact that skbs in error queue are limited by sk->sk_rcvbuf means that error messages can be dropped if socket receive queues are full, which is an orthogonal issue. In future kernels, we could use a separate sk->sk_error_mem_alloc counter specifically for the error queue. Fixes: 0de2a5c4b824 ("tcp: avoid atomic operations on sk->sk_rmem_alloc") Signed-off-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250331075946.31960-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-25tcp: avoid atomic operations on sk->sk_rmem_allocEric Dumazet1-0/+15
TCP uses generic skb_set_owner_r() and sock_rfree() for received packets, with socket lock being owned. Switch to private versions, avoiding two atomic operations per packet. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250320121604.3342831-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-25tcp: support TCP_RTO_MIN_US for set/getsockopt useJason Xing1-1/+1
Support adjusting/reading RTO MIN for socket level by using set/getsockopt(). This new option has the same effect as TCP_BPF_RTO_MIN, which means it doesn't affect RTAX_RTO_MIN usage (by using ip route...). Considering that bpf option was implemented before this patch, so we need to use a standalone new option for pure tcp set/getsockopt() use. When the socket is created, its icsk_rto_min is set to the default value that is controlled by sysctl_tcp_rto_min_us. Then if application calls setsockopt() with TCP_RTO_MIN_US flag to pass a valid value, then icsk_rto_min will be overridden in jiffies unit. This patch adds WRITE_ONCE/READ_ONCE to avoid data-race around icsk_rto_min. Signed-off-by: Jason Xing <kerneljasonxing@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250317120314.41404-2-kerneljasonxing@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-24tcp: move icsk_clean_acked to a better locationEric Dumazet1-2/+2
As a followup of my presentation in Zagreb for netdev 0x19: icsk_clean_acked is only used by TCP when/if CONFIG_TLS_DEVICE is enabled from tcp_ack(). Rename it to tcp_clean_acked, move it to tcp_sock structure in the tcp_sock_read_rx for better cache locality in TCP fast path. Define this field only when CONFIG_TLS_DEVICE is enabled saving 8 bytes on configs not using it. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250317085313.2023214-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-17tcp: Pass flags to __tcp_send_ackIlpo Järvinen1-1/+1
Accurate ECN needs to send custom flags to handle IP-ECN field reflection during handshake. Signed-off-by: Ilpo Järvinen <ij@kernel.org> Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2025-03-17tcp: add new TCP_TW_ACK_OOW state and allow ECN bits in TOSIlpo Järvinen1-1/+2
ECN bits in TOS are always cleared when sending in ACKs in TW. Clearing them is problematic for TCP flows that used Accurate ECN because ECN bits decide which service queue the packet is placed into (L4S vs Classic). Effectively, TW ACKs are always downgraded from L4S to Classic queue which might impact, e.g., delay the ACK will experience on the path compared with the other packets of the flow. Change the TW ACK sending code to differentiate: - In tcp_v4_send_reset(), commit ba9e04a7ddf4f ("ip: fix tos reflection in ack and reset packets") cleans ECN bits for TW reset and this is not affected. - In tcp_v4_timewait_ack(), ECN bits for all TW ACKs are cleaned. But now only ECN bits of ACKs for oow data or paws_reject are cleaned, and ECN bits of other ACKs will not be cleaned. - In tcp_v4_reqsk_send_ack(), commit 66b13d99d96a1 ("ipv4: tcp: fix TOS value in ACK messages sent from TIME_WAIT") did not clean ECN bits of ACKs for oow data or paws_reject. But now the ECN bits rae cleaned for these ACKs. Signed-off-by: Ilpo Järvinen <ij@kernel.org> Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2025-03-17tcp: helpers for ECN mode handlingIlpo Järvinen1-4/+40
Create helpers for TCP ECN modes. No functional changes. Signed-off-by: Ilpo Järvinen <ij@kernel.org> Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2025-03-17tcp: extend TCP flags to allow AE bit/ACE fieldIlpo Järvinen1-2/+9
With AccECN, there's one additional TCP flag to be used (AE) and ACE field that overloads the definition of AE, CWR, and ECE flags. As tcp_flags was previously only 1 byte, the byte-order stuff needs to be added to it's handling. Signed-off-by: Ilpo Järvinen <ij@kernel.org> Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2025-03-17tcp: use BIT() macro in include/net/tcp.hChia-Yu Chang1-10/+11
Use BIT() macro for TCP flags field and TCP congestion control flags that will be used by the congestion control algorithm. No functional changes. Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Reviewed-by: Ilpo Järvinen <ij@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2025-03-07tcp: ulp: diag: more info without CAP_NET_ADMINMatthieu Baerts (NGI0)1-2/+2
When introduced in commit 61723b393292 ("tcp: ulp: add functions to dump ulp-specific information"), the whole ULP diag info has been exported only if the requester had CAP_NET_ADMIN. It looks like not everything is sensitive, and some info can be exported to all users in order to ease the debugging from the userspace side without requiring additional capabilities. Each layer should then decide what can be exposed to everybody. The 'net_admin' boolean is then passed to the different layers. On kTLS side, it looks like there is nothing sensitive there: version, cipher type, tx/rx user config type, plus some flags. So, only some metadata about the configuration, no cryptographic info like keys, etc. Then, everything can be exported to all users. On MPTCP side, that's different. The MPTCP-related sequence numbers per subflow should certainly not be exposed to everybody. For example, the DSS mapping and ssn_offset would give all users on the system access to narrow ranges of values for the subflow TCP sequence numbers and MPTCP-level DSNs, and then ease packet injection. The TCP diag interface doesn't expose the TCP sequence numbers for TCP sockets, so best to do the same here. The rest -- token, IDs, flags -- can be exported to everybody. Acked-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250306-net-next-tcp-ulp-diag-net-admin-v1-2-06afdd860fc9@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-03tcp: add a drop_reason pointer to tcp_check_req()Eric Dumazet1-1/+1
We want to add new drop reasons for packets dropped in 3WHS in the following patches. tcp_rcv_state_process() has to set reason to TCP_FASTOPEN, because tcp_check_req() will conditionally overwrite the drop_reason. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250301201424.2046477-2-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-27Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-0/+8
Cross-merge networking fixes after downstream PR (net-6.14-rc5). Conflicts: drivers/net/ethernet/cadence/macb_main.c fa52f15c745c ("net: cadence: macb: Synchronize stats calculations") 75696dd0fd72 ("net: cadence: macb: Convert to get_stats64") https://lore.kernel.org/20250224125848.68ee63e5@canb.auug.org.au Adjacent changes: drivers/net/ethernet/intel/ice/ice_sriov.c 79990cf5e7ad ("ice: Fix deinitializing VF in error path") a203163274a4 ("ice: simplify VF MSI-X managing") net/ipv4/tcp.c 18912c520674 ("tcp: devmem: don't write truncated dmabuf CMSGs to userspace") 297d389e9e5b ("net: prefix devmem specific helpers") net/mptcp/subflow.c 8668860b0ad3 ("mptcp: reset when MPTCP opts are dropped after join") c3349a22c200 ("mptcp: consolidate subflow cleanup") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-21Merge tag 'for-netdev' of ↵Jakub Kicinski1-2/+5
https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next Martin KaFai Lau says: ==================== pull-request: bpf-next 2025-02-20 We've added 19 non-merge commits during the last 8 day(s) which contain a total of 35 files changed, 1126 insertions(+), 53 deletions(-). The main changes are: 1) Add TCP_RTO_MAX_MS support to bpf_set/getsockopt, from Jason Xing 2) Add network TX timestamping support to BPF sock_ops, from Jason Xing 3) Add TX metadata Launch Time support, from Song Yoong Siang * tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: igc: Add launch time support to XDP ZC igc: Refactor empty frame insertion for launch time support net: stmmac: Add launch time support to XDP ZC selftests/bpf: Add launch time request to xdp_hw_metadata xsk: Add launch time hardware offload support to XDP Tx metadata selftests/bpf: Add simple bpf tests in the tx path for timestamping feature bpf: Support selective sampling for bpf timestamping bpf: Add BPF_SOCK_OPS_TSTAMP_SENDMSG_CB callback bpf: Add BPF_SOCK_OPS_TSTAMP_ACK_CB callback bpf: Add BPF_SOCK_OPS_TSTAMP_SND_HW_CB callback bpf: Add BPF_SOCK_OPS_TSTAMP_SND_SW_CB callback bpf: Add BPF_SOCK_OPS_TSTAMP_SCHED_CB callback net-timestamp: Prepare for isolating two modes of SO_TIMESTAMPING bpf: Disable unsafe helpers in TX timestamping callbacks bpf: Prevent unsafe access to the sock fields in the BPF timestamping callback bpf: Prepare the sock_ops ctx and call bpf prog for TX timestamping bpf: Add networking timestamping support to bpf_get/setsockopt() selftests/bpf: Add rto max for bpf_setsockopt test bpf: Support TCP_RTO_MAX_MS for bpf_setsockopt ==================== Link: https://patch.msgid.link/20250221022104.386462-1-martin.lau@linux.dev Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-20Merge tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpfLinus Torvalds1-0/+8
Pull BPF fixes from Daniel Borkmann: - Fix a soft-lockup in BPF arena_map_free on 64k page size kernels (Alan Maguire) - Fix a missing allocation failure check in BPF verifier's acquire_lock_state (Kumar Kartikeya Dwivedi) - Fix a NULL-pointer dereference in trace_kfree_skb by adding kfree_skb to the raw_tp_null_args set (Kuniyuki Iwashima) - Fix a deadlock when freeing BPF cgroup storage (Abel Wu) - Fix a syzbot-reported deadlock when holding BPF map's freeze_mutex (Andrii Nakryiko) - Fix a use-after-free issue in bpf_test_init when eth_skb_pkt_type is accessing skb data not containing an Ethernet header (Shigeru Yoshida) - Fix skipping non-existing keys in generic_map_lookup_batch (Yan Zhai) - Several BPF sockmap fixes to address incorrect TCP copied_seq calculations, which prevented correct data reads from recv(2) in user space (Jiayuan Chen) - Two fixes for BPF map lookup nullness elision (Daniel Xu) - Fix a NULL-pointer dereference from vmlinux BTF lookup in bpf_sk_storage_tracing_allowed (Jared Kangas) * tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf: selftests: bpf: test batch lookup on array of maps with holes bpf: skip non exist keys in generic_map_lookup_batch bpf: Handle allocation failure in acquire_lock_state bpf: verifier: Disambiguate get_constant_map_key() errors bpf: selftests: Test constant key extraction on irrelevant maps bpf: verifier: Do not extract constant map keys for irrelevant maps bpf: Fix softlockup in arena_map_free on 64k page kernel net: Add rx_skb of kfree_skb to raw_tp_null_args[]. bpf: Fix deadlock when freeing cgroup storage selftests/bpf: Add strparser test for bpf selftests/bpf: Fix invalid flag of recv() bpf: Disable non stream socket for strparser bpf: Fix wrong copied_seq calculation strparser: Add read_sock callback bpf: avoid holding freeze_mutex during mmap operation bpf: unify VM_WRITE vs VM_MAYWRITE use in BPF map mmaping logic selftests/bpf: Adjust data size to have ETH_HLEN bpf, test_run: Fix use-after-free issue in eth_skb_pkt_type() bpf: Remove unnecessary BTF lookups in bpf_sk_storage_tracing_allowed
2025-02-20bpf: Add BPF_SOCK_OPS_TSTAMP_ACK_CB callbackJason Xing1-2/+4
Support the ACK case for bpf timestamping. Add a new sock_ops callback, BPF_SOCK_OPS_TSTAMP_ACK_CB. This callback will occur at the same timestamping point as the user space's SCM_TSTAMP_ACK. The BPF program can use it to get the same SCM_TSTAMP_ACK timestamp without modifying the user-space application. This patch extends txstamp_ack to two bits: 1 stands for SO_TIMESTAMPING mode, 2 bpf extension. Signed-off-by: Jason Xing <kerneljasonxing@gmail.com> Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20250220072940.99994-10-kerneljasonxing@gmail.com
2025-02-20bpf: Prevent unsafe access to the sock fields in the BPF timestamping callbackJason Xing1-0/+1
The subsequent patch will implement BPF TX timestamping. It will call the sockops BPF program without holding the sock lock. This breaks the current assumption that all sock ops programs will hold the sock lock. The sock's fields of the uapi's bpf_sock_ops requires this assumption. To address this, a new "u8 is_locked_tcp_sock;" field is added. This patch sets it in the current sock_ops callbacks. The "is_fullsock" test is then replaced by the "is_locked_tcp_sock" test during sock_ops_convert_ctx_access(). The new TX timestamping callbacks added in the subsequent patch will not have this set. This will prevent unsafe access from the new timestamping callbacks. Potentially, we could allow read-only access. However, this would require identifying which callback is read-safe-only and also requires additional BPF instruction rewrites in the covert_ctx. Since the BPF program can always read everything from a socket (e.g., by using bpf_core_cast), this patch keeps it simple and disables all read and write access to any socket fields through the bpf_sock_ops UAPI from the new TX timestamping callback. Moreover, note that some of the fields in bpf_sock_ops are specific to tcp_sock, and sock_ops currently only supports tcp_sock. In the future, UDP timestamping will be added, which will also break this assumption. The same idea used in this patch will be reused. Considering that the current sock_ops only supports tcp_sock, the variable is named is_locked_"tcp"_sock. Signed-off-by: Jason Xing <kerneljasonxing@gmail.com> Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Link: https://patch.msgid.link/20250220072940.99994-4-kerneljasonxing@gmail.com
2025-02-20Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-0/+14
Cross-merge networking fixes after downstream PR (net-6.14-rc4). No conflicts or adjacent changes. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-20tcp: drop secpath at the same time as we currently drop dstSabrina Dubroca1-0/+14
Xiumei reported hitting the WARN in xfrm6_tunnel_net_exit while running tests that boil down to: - create a pair of netns - run a basic TCP test over ipcomp6 - delete the pair of netns The xfrm_state found on spi_byaddr was not deleted at the time we delete the netns, because we still have a reference on it. This lingering reference comes from a secpath (which holds a ref on the xfrm_state), which is still attached to an skb. This skb is not leaked, it ends up on sk_receive_queue and then gets defer-free'd by skb_attempt_defer_free. The problem happens when we defer freeing an skb (push it on one CPU's defer_list), and don't flush that list before the netns is deleted. In that case, we still have a reference on the xfrm_state that we don't expect at this point. We already drop the skb's dst in the TCP receive path when it's no longer needed, so let's also drop the secpath. At this point, tcp_filter has already called into the LSM hooks that may require the secpath, so it should not be needed anymore. However, in some of those places, the MPTCP extension has just been attached to the skb, so we cannot simply drop all extensions. Fixes: 68822bdf76f1 ("net: generalize skb freeing deferral to per-cpu lists") Reported-by: Xiumei Mu <xmu@redhat.com> Signed-off-by: Sabrina Dubroca <sd@queasysnail.net> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/5055ba8f8f72bdcb602faa299faca73c280b7735.1739743613.git.sd@queasysnail.net Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-02-11tcp: add the ability to control max RTOEric Dumazet1-5/+11
Currently, TCP stack uses a constant (120 seconds) to limit the RTO value exponential growth. Some applications want to set a lower value. Add TCP_RTO_MAX_MS socket option to set a value (in ms) between 1 and 120 seconds. It is discouraged to change the socket rto max on a live socket, as it might lead to unexpected disconnects. Following patch is adding a netns sysctl to control the default value at socket creation time. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-02-11tcp: add a @pace_delay parameter to tcp_reset_xmit_timer()Eric Dumazet1-4/+6
We want to factorize calls to inet_csk_reset_xmit_timer(), to ease TCP_RTO_MAX change. Current users want to add tcp_pacing_delay(sk) to the timeout. Remaining calls to inet_csk_reset_xmit_timer() do not add the pacing delay. Following patch will convert them, passing false for @pace_delay. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-02-11tcp: remove tcp_reset_xmit_timer() @max_when argumentEric Dumazet1-4/+3
All callers use TCP_RTO_MAX, we can factorize this constant, becoming a variable soon. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-02-07tcp: rename inet_csk_{delete|reset}_keepalive_timer()Eric Dumazet1-0/+1
inet_csk_delete_keepalive_timer() and inet_csk_reset_keepalive_timer() are only used from core TCP, there is no need to export them. Replace their prefix by tcp. Move them to net/ipv4/tcp_timer.c and make tcp_delete_keepalive_timer() static. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Reviewed-by: Joe Damato <jdamato@fastly.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250206094605.2694118-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-01-29bpf: Fix wrong copied_seq calculationJiayuan Chen1-0/+8
'sk->copied_seq' was updated in the tcp_eat_skb() function when the action of a BPF program was SK_REDIRECT. For other actions, like SK_PASS, the update logic for 'sk->copied_seq' was moved to tcp_bpf_recvmsg_parser() to ensure the accuracy of the 'fionread' feature. It works for a single stream_verdict scenario, as it also modified sk_data_ready->sk_psock_verdict_data_ready->tcp_read_skb to remove updating 'sk->copied_seq'. However, for programs where both stream_parser and stream_verdict are active (strparser purpose), tcp_read_sock() was used instead of tcp_read_skb() (sk_data_ready->strp_data_ready->tcp_read_sock). tcp_read_sock() now still updates 'sk->copied_seq', leading to duplicate updates. In summary, for strparser + SK_PASS, copied_seq is redundantly calculated in both tcp_read_sock() and tcp_bpf_recvmsg_parser(). The issue causes incorrect copied_seq calculations, which prevent correct data reads from the recv() interface in user-land. We do not want to add new proto_ops to implement a new version of tcp_read_sock, as this would introduce code complexity [1]. We could have added noack and copied_seq to desc, and then called ops->read_sock. However, unfortunately, other modules didn’t fully initialize desc to zero. So, for now, we are directly calling tcp_read_sock_noack() in tcp_bpf.c. [1]: https://lore.kernel.org/bpf/20241218053408.437295-1-mrpre@163.com Fixes: e5c6de5fa025 ("bpf, sockmap: Incorrectly handling copied_seq") Suggested-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: Jiayuan Chen <mrpre@163.com> Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://patch.msgid.link/20250122100917.49845-3-mrpre@163.com
2024-12-09net: reformat kdoc return statementsJakub Kicinski1-1/+1
kernel-doc -Wall warns about missing Return: statement for non-void functions. We have a number of kdocs in our headers which are missing the colon, IOW they use * Return some value or * Returns some value Having the colon makes some sense, it should help kdoc parser avoid false positives. So add them. This is mostly done with a sed script, and removing the unnecessary cases (mostly the comments which aren't kdoc). Acked-by: Johannes Berg <johannes@sipsolutions.net> Acked-by: Richard Cochran <richardcochran@gmail.com> Acked-by: Sergey Ryazanov <ryazanov.s.a@gmail.com> Reviewed-by: Edward Cree <ecree.xilinx@gmail.com> Acked-by: Alexandra Winter <wintera@linux.ibm.com> Acked-by: Pablo Neira Ayuso <pablo@netfilter.org> Link: https://patch.msgid.link/20241205165914.1071102-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-10-30tcp: add more warn of socket in tcp_send_loss_probe()Jason Xing1-1/+2
Add two fields to print in the helper which here covers tcp_send_loss_probe(). Link: https://lore.kernel.org/all/5632e043-bdba-4d75-bc7e-bf58014492fd@redhat.com/ Suggested-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Jason Xing <kernelxing@tencent.com> Cc: Neal Cardwell <ncardwell@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2024-10-30tcp: add a common helper to debug the underlying issueJason Xing1-11/+14
Following the commit c8770db2d544 ("tcp: check skb is non-NULL in tcp_rto_delta_us()"), we decided to add a helper so that it's easier to get verbose warning on either cases. Link: https://lore.kernel.org/all/5632e043-bdba-4d75-bc7e-bf58014492fd@redhat.com/ Suggested-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Jason Xing <kernelxing@tencent.com> Cc: Neal Cardwell <ncardwell@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2024-10-01tcp: Fix spelling mistake "emtpy" -> "empty"Colin Ian King1-1/+1
There is a spelling mistake in a WARN_ONCE message. Fix it. Signed-off-by: Colin Ian King <colin.i.king@gmail.com> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Link: https://patch.msgid.link/20240924080545.1324962-1-colin.i.king@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-09-23tcp: check skb is non-NULL in tcp_rto_delta_us()Josh Hunt1-2/+19
We have some machines running stock Ubuntu 20.04.6 which is their 5.4.0-174-generic kernel that are running ceph and recently hit a null ptr dereference in tcp_rearm_rto(). Initially hitting it from the TLP path, but then later we also saw it getting hit from the RACK case as well. Here are examples of the oops messages we saw in each of those cases: Jul 26 15:05:02 rx [11061395.780353] BUG: kernel NULL pointer dereference, address: 0000000000000020 Jul 26 15:05:02 rx [11061395.787572] #PF: supervisor read access in kernel mode Jul 26 15:05:02 rx [11061395.792971] #PF: error_code(0x0000) - not-present page Jul 26 15:05:02 rx [11061395.798362] PGD 0 P4D 0 Jul 26 15:05:02 rx [11061395.801164] Oops: 0000 [#1] SMP NOPTI Jul 26 15:05:02 rx [11061395.805091] CPU: 0 PID: 9180 Comm: msgr-worker-1 Tainted: G W 5.4.0-174-generic #193-Ubuntu Jul 26 15:05:02 rx [11061395.814996] Hardware name: Supermicro SMC 2x26 os-gen8 64C NVME-Y 256G/H12SSW-NTR, BIOS 2.5.V1.2U.NVMe.UEFI 05/09/2023 Jul 26 15:05:02 rx [11061395.825952] RIP: 0010:tcp_rearm_rto+0xe4/0x160 Jul 26 15:05:02 rx [11061395.830656] Code: 87 ca 04 00 00 00 5b 41 5c 41 5d 5d c3 c3 49 8b bc 24 40 06 00 00 eb 8d 48 bb cf f7 53 e3 a5 9b c4 20 4c 89 ef e8 0c fe 0e 00 <48> 8b 78 20 48 c1 ef 03 48 89 f8 41 8b bc 24 80 04 00 00 48 f7 e3 Jul 26 15:05:02 rx [11061395.849665] RSP: 0018:ffffb75d40003e08 EFLAGS: 00010246 Jul 26 15:05:02 rx [11061395.855149] RAX: 0000000000000000 RBX: 20c49ba5e353f7cf RCX: 0000000000000000 Jul 26 15:05:02 rx [11061395.862542] RDX: 0000000062177c30 RSI: 000000000000231c RDI: ffff9874ad283a60 Jul 26 15:05:02 rx [11061395.869933] RBP: ffffb75d40003e20 R08: 0000000000000000 R09: ffff987605e20aa8 Jul 26 15:05:02 rx [11061395.877318] R10: ffffb75d40003f00 R11: ffffb75d4460f740 R12: ffff9874ad283900 Jul 26 15:05:02 rx [11061395.884710] R13: ffff9874ad283a60 R14: ffff9874ad283980 R15: ffff9874ad283d30 Jul 26 15:05:02 rx [11061395.892095] FS: 00007f1ef4a2e700(0000) GS:ffff987605e00000(0000) knlGS:0000000000000000 Jul 26 15:05:02 rx [11061395.900438] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 Jul 26 15:05:02 rx [11061395.906435] CR2: 0000000000000020 CR3: 0000003e450ba003 CR4: 0000000000760ef0 Jul 26 15:05:02 rx [11061395.913822] PKRU: 55555554 Jul 26 15:05:02 rx [11061395.916786] Call Trace: Jul 26 15:05:02 rx [11061395.919488] Jul 26 15:05:02 rx [11061395.921765] ? show_regs.cold+0x1a/0x1f Jul 26 15:05:02 rx [11061395.925859] ? __die+0x90/0xd9 Jul 26 15:05:02 rx [11061395.929169] ? no_context+0x196/0x380 Jul 26 15:05:02 rx [11061395.933088] ? ip6_protocol_deliver_rcu+0x4e0/0x4e0 Jul 26 15:05:02 rx [11061395.938216] ? ip6_sublist_rcv_finish+0x3d/0x50 Jul 26 15:05:02 rx [11061395.943000] ? __bad_area_nosemaphore+0x50/0x1a0 Jul 26 15:05:02 rx [11061395.947873] ? bad_area_nosemaphore+0x16/0x20 Jul 26 15:05:02 rx [11061395.952486] ? do_user_addr_fault+0x267/0x450 Jul 26 15:05:02 rx [11061395.957104] ? ipv6_list_rcv+0x112/0x140 Jul 26 15:05:02 rx [11061395.961279] ? __do_page_fault+0x58/0x90 Jul 26 15:05:02 rx [11061395.965458] ? do_page_fault+0x2c/0xe0 Jul 26 15:05:02 rx [11061395.969465] ? page_fault+0x34/0x40 Jul 26 15:05:02 rx [11061395.973217] ? tcp_rearm_rto+0xe4/0x160 Jul 26 15:05:02 rx [11061395.977313] ? tcp_rearm_rto+0xe4/0x160 Jul 26 15:05:02 rx [11061395.981408] tcp_send_loss_probe+0x10b/0x220 Jul 26 15:05:02 rx [11061395.985937] tcp_write_timer_handler+0x1b4/0x240 Jul 26 15:05:02 rx [11061395.990809] tcp_write_timer+0x9e/0xe0 Jul 26 15:05:02 rx [11061395.994814] ? tcp_write_timer_handler+0x240/0x240 Jul 26 15:05:02 rx [11061395.999866] call_timer_fn+0x32/0x130 Jul 26 15:05:02 rx [11061396.003782] __run_timers.part.0+0x180/0x280 Jul 26 15:05:02 rx [11061396.008309] ? recalibrate_cpu_khz+0x10/0x10 Jul 26 15:05:02 rx [11061396.012841] ? native_x2apic_icr_write+0x30/0x30 Jul 26 15:05:02 rx [11061396.017718] ? lapic_next_event+0x21/0x30 Jul 26 15:05:02 rx [11061396.021984] ? clockevents_program_event+0x8f/0xe0 Jul 26 15:05:02 rx [11061396.027035] run_timer_softirq+0x2a/0x50 Jul 26 15:05:02 rx [11061396.031212] __do_softirq+0xd1/0x2c1 Jul 26 15:05:02 rx [11061396.035044] do_softirq_own_stack+0x2a/0x40 Jul 26 15:05:02 rx [11061396.039480] Jul 26 15:05:02 rx [11061396.041840] do_softirq.part.0+0x46/0x50 Jul 26 15:05:02 rx [11061396.046022] __local_bh_enable_ip+0x50/0x60 Jul 26 15:05:02 rx [11061396.050460] _raw_spin_unlock_bh+0x1e/0x20 Jul 26 15:05:02 rx [11061396.054817] nf_conntrack_tcp_packet+0x29e/0xbe0 [nf_conntrack] Jul 26 15:05:02 rx [11061396.060994] ? get_l4proto+0xe7/0x190 [nf_conntrack] Jul 26 15:05:02 rx [11061396.066220] nf_conntrack_in+0xe9/0x670 [nf_conntrack] Jul 26 15:05:02 rx [11061396.071618] ipv6_conntrack_local+0x14/0x20 [nf_conntrack] Jul 26 15:05:02 rx [11061396.077356] nf_hook_slow+0x45/0xb0 Jul 26 15:05:02 rx [11061396.081098] ip6_xmit+0x3f0/0x5d0 Jul 26 15:05:02 rx [11061396.084670] ? ipv6_anycast_cleanup+0x50/0x50 Jul 26 15:05:02 rx [11061396.089282] ? __sk_dst_check+0x38/0x70 Jul 26 15:05:02 rx [11061396.093381] ? inet6_csk_route_socket+0x13b/0x200 Jul 26 15:05:02 rx [11061396.098346] inet6_csk_xmit+0xa7/0xf0 Jul 26 15:05:02 rx [11061396.102263] __tcp_transmit_skb+0x550/0xb30 Jul 26 15:05:02 rx [11061396.106701] tcp_write_xmit+0x3c6/0xc20 Jul 26 15:05:02 rx [11061396.110792] ? __alloc_skb+0x98/0x1d0 Jul 26 15:05:02 rx [11061396.114708] __tcp_push_pending_frames+0x37/0x100 Jul 26 15:05:02 rx [11061396.119667] tcp_push+0xfd/0x100 Jul 26 15:05:02 rx [11061396.123150] tcp_sendmsg_locked+0xc70/0xdd0 Jul 26 15:05:02 rx [11061396.127588] tcp_sendmsg+0x2d/0x50 Jul 26 15:05:02 rx [11061396.131245] inet6_sendmsg+0x43/0x70 Jul 26 15:05:02 rx [11061396.135075] __sock_sendmsg+0x48/0x70 Jul 26 15:05:02 rx [11061396.138994] ____sys_sendmsg+0x212/0x280 Jul 26 15:05:02 rx [11061396.143172] ___sys_sendmsg+0x88/0xd0 Jul 26 15:05:02 rx [11061396.147098] ? __seccomp_filter+0x7e/0x6b0 Jul 26 15:05:02 rx [11061396.151446] ? __switch_to+0x39c/0x460 Jul 26 15:05:02 rx [11061396.155453] ? __switch_to_asm+0x42/0x80 Jul 26 15:05:02 rx [11061396.159636] ? __switch_to_asm+0x5a/0x80 Jul 26 15:05:02 rx [11061396.163816] __sys_sendmsg+0x5c/0xa0 Jul 26 15:05:02 rx [11061396.167647] __x64_sys_sendmsg+0x1f/0x30 Jul 26 15:05:02 rx [11061396.171832] do_syscall_64+0x57/0x190 Jul 26 15:05:02 rx [11061396.175748] entry_SYSCALL_64_after_hwframe+0x5c/0xc1 Jul 26 15:05:02 rx [11061396.181055] RIP: 0033:0x7f1ef692618d Jul 26 15:05:02 rx [11061396.184893] Code: 28 89 54 24 1c 48 89 74 24 10 89 7c 24 08 e8 ca ee ff ff 8b 54 24 1c 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 2f 44 89 c7 48 89 44 24 08 e8 fe ee ff ff 48 Jul 26 15:05:02 rx [11061396.203889] RSP: 002b:00007f1ef4a26aa0 EFLAGS: 00000293 ORIG_RAX: 000000000000002e Jul 26 15:05:02 rx [11061396.211708] RAX: ffffffffffffffda RBX: 000000000000084b RCX: 00007f1ef692618d Jul 26 15:05:02 rx [11061396.219091] RDX: 0000000000004000 RSI: 00007f1ef4a26b10 RDI: 0000000000000275 Jul 26 15:05:02 rx [11061396.226475] RBP: 0000000000004000 R08: 0000000000000000 R09: 0000000000000020 Jul 26 15:05:02 rx [11061396.233859] R10: 0000000000000000 R11: 0000000000000293 R12: 000000000000084b Jul 26 15:05:02 rx [11061396.241243] R13: 00007f1ef4a26b10 R14: 0000000000000275 R15: 000055592030f1e8 Jul 26 15:05:02 rx [11061396.248628] Modules linked in: vrf bridge stp llc vxlan ip6_udp_tunnel udp_tunnel nls_iso8859_1 amd64_edac_mod edac_mce_amd kvm_amd kvm crct10dif_pclmul ghash_clmulni_intel aesni_intel crypto_simd cryptd glue_helper wmi_bmof ipmi_ssif input_leds joydev rndis_host cdc_ether usbnet mii ast drm_vram_helper ttm drm_kms_helper i2c_algo_bit fb_sys_fops syscopyarea sysfillrect sysimgblt ccp mac_hid ipmi_si ipmi_devintf ipmi_msghandler nft_ct sch_fq_codel nf_tables_set nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nf_tables nfnetlink ramoops reed_solomon efi_pstore drm ip_tables x_tables autofs4 raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c raid0 multipath linear mlx5_ib ib_uverbs ib_core raid1 mlx5_core hid_generic pci_hyperv_intf crc32_pclmul tls usbhid ahci mlxfw bnxt_en libahci hid nvme i2c_piix4 nvme_core wmi Jul 26 15:05:02 rx [11061396.324334] CR2: 0000000000000020 Jul 26 15:05:02 rx [11061396.327944] ---[ end trace 68a2b679d1cfb4f1 ]--- Jul 26 15:05:02 rx [11061396.433435] RIP: 0010:tcp_rearm_rto+0xe4/0x160 Jul 26 15:05:02 rx [11061396.438137] Code: 87 ca 04 00 00 00 5b 41 5c 41 5d 5d c3 c3 49 8b bc 24 40 06 00 00 eb 8d 48 bb cf f7 53 e3 a5 9b c4 20 4c 89 ef e8 0c fe 0e 00 <48> 8b 78 20 48 c1 ef 03 48 89 f8 41 8b bc 24 80 04 00 00 48 f7 e3 Jul 26 15:05:02 rx [11061396.457144] RSP: 0018:ffffb75d40003e08 EFLAGS: 00010246 Jul 26 15:05:02 rx [11061396.462629] RAX: 0000000000000000 RBX: 20c49ba5e353f7cf RCX: 0000000000000000 Jul 26 15:05:02 rx [11061396.470012] RDX: 0000000062177c30 RSI: 000000000000231c RDI: ffff9874ad283a60 Jul 26 15:05:02 rx [11061396.477396] RBP: ffffb75d40003e20 R08: 0000000000000000 R09: ffff987605e20aa8 Jul 26 15:05:02 rx [11061396.484779] R10: ffffb75d40003f00 R11: ffffb75d4460f740 R12: ffff9874ad283900 Jul 26 15:05:02 rx [11061396.492164] R13: ffff9874ad283a60 R14: ffff9874ad283980 R15: ffff9874ad283d30 Jul 26 15:05:02 rx [11061396.499547] FS: 00007f1ef4a2e700(0000) GS:ffff987605e00000(0000) knlGS:0000000000000000 Jul 26 15:05:02 rx [11061396.507886] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 Jul 26 15:05:02 rx [11061396.513884] CR2: 0000000000000020 CR3: 0000003e450ba003 CR4: 0000000000760ef0 Jul 26 15:05:02 rx [11061396.521267] PKRU: 55555554 Jul 26 15:05:02 rx [11061396.524230] Kernel panic - not syncing: Fatal exception in interrupt Jul 26 15:05:02 rx [11061396.530885] Kernel Offset: 0x1b200000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) Jul 26 15:05:03 rx [11061396.660181] ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]--- After we hit this we disabled TLP by setting tcp_early_retrans to 0 and then hit the crash in the RACK case: Aug 7 07:26:16 rx [1006006.265582] BUG: kernel NULL pointer dereference, address: 0000000000000020 Aug 7 07:26:16 rx [1006006.272719] #PF: supervisor read access in kernel mode Aug 7 07:26:16 rx [1006006.278030] #PF: error_code(0x0000) - not-present page Aug 7 07:26:16 rx [1006006.283343] PGD 0 P4D 0 Aug 7 07:26:16 rx [1006006.286057] Oops: 0000 [#1] SMP NOPTI Aug 7 07:26:16 rx [1006006.289896] CPU: 5 PID: 0 Comm: swapper/5 Tainted: G W 5.4.0-174-generic #193-Ubuntu Aug 7 07:26:16 rx [1006006.299107] Hardware name: Supermicro SMC 2x26 os-gen8 64C NVME-Y 256G/H12SSW-NTR, BIOS 2.5.V1.2U.NVMe.UEFI 05/09/2023 Aug 7 07:26:16 rx [1006006.309970] RIP: 0010:tcp_rearm_rto+0xe4/0x160 Aug 7 07:26:16 rx [1006006.314584] Code: 87 ca 04 00 00 00 5b 41 5c 41 5d 5d c3 c3 49 8b bc 24 40 06 00 00 eb 8d 48 bb cf f7 53 e3 a5 9b c4 20 4c 89 ef e8 0c fe 0e 00 <48> 8b 78 20 48 c1 ef 03 48 89 f8 41 8b bc 24 80 04 00 00 48 f7 e3 Aug 7 07:26:16 rx [1006006.333499] RSP: 0018:ffffb42600a50960 EFLAGS: 00010246 Aug 7 07:26:16 rx [1006006.338895] RAX: 0000000000000000 RBX: 20c49ba5e353f7cf RCX: 0000000000000000 Aug 7 07:26:16 rx [1006006.346193] RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff92d687ed8160 Aug 7 07:26:16 rx [1006006.353489] RBP: ffffb42600a50978 R08: 0000000000000000 R09: 00000000cd896dcc Aug 7 07:26:16 rx [1006006.360786] R10: ffff92dc3404f400 R11: 0000000000000001 R12: ffff92d687ed8000 Aug 7 07:26:16 rx [1006006.368084] R13: ffff92d687ed8160 R14: 00000000cd896dcc R15: 00000000cd8fca81 Aug 7 07:26:16 rx [1006006.375381] FS: 0000000000000000(0000) GS:ffff93158ad40000(0000) knlGS:0000000000000000 Aug 7 07:26:16 rx [1006006.383632] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 Aug 7 07:26:16 rx [1006006.389544] CR2: 0000000000000020 CR3: 0000003e775ce006 CR4: 0000000000760ee0 Aug 7 07:26:16 rx [1006006.396839] PKRU: 55555554 Aug 7 07:26:16 rx [1006006.399717] Call Trace: Aug 7 07:26:16 rx [1006006.402335] Aug 7 07:26:16 rx [1006006.404525] ? show_regs.cold+0x1a/0x1f Aug 7 07:26:16 rx [1006006.408532] ? __die+0x90/0xd9 Aug 7 07:26:16 rx [1006006.411760] ? no_context+0x196/0x380 Aug 7 07:26:16 rx [1006006.415599] ? __bad_area_nosemaphore+0x50/0x1a0 Aug 7 07:26:16 rx [1006006.420392] ? _raw_spin_lock+0x1e/0x30 Aug 7 07:26:16 rx [1006006.424401] ? bad_area_nosemaphore+0x16/0x20 Aug 7 07:26:16 rx [1006006.428927] ? do_user_addr_fault+0x267/0x450 Aug 7 07:26:16 rx [1006006.433450] ? __do_page_fault+0x58/0x90 Aug 7 07:26:16 rx [1006006.437542] ? do_page_fault+0x2c/0xe0 Aug 7 07:26:16 rx [1006006.441470] ? page_fault+0x34/0x40 Aug 7 07:26:16 rx [1006006.445134] ? tcp_rearm_rto+0xe4/0x160 Aug 7 07:26:16 rx [1006006.449145] tcp_ack+0xa32/0xb30 Aug 7 07:26:16 rx [1006006.452542] tcp_rcv_established+0x13c/0x670 Aug 7 07:26:16 rx [1006006.456981] ? sk_filter_trim_cap+0x48/0x220 Aug 7 07:26:16 rx [1006006.461419] tcp_v6_do_rcv+0xdb/0x450 Aug 7 07:26:16 rx [1006006.465257] tcp_v6_rcv+0xc2b/0xd10 Aug 7 07:26:16 rx [1006006.468918] ip6_protocol_deliver_rcu+0xd3/0x4e0 Aug 7 07:26:16 rx [1006006.473706] ip6_input_finish+0x15/0x20 Aug 7 07:26:16 rx [1006006.477710] ip6_input+0xa2/0xb0 Aug 7 07:26:16 rx [1006006.481109] ? ip6_protocol_deliver_rcu+0x4e0/0x4e0 Aug 7 07:26:16 rx [1006006.486151] ip6_sublist_rcv_finish+0x3d/0x50 Aug 7 07:26:16 rx [1006006.490679] ip6_sublist_rcv+0x1aa/0x250 Aug 7 07:26:16 rx [1006006.494779] ? ip6_rcv_finish_core.isra.0+0xa0/0xa0 Aug 7 07:26:16 rx [1006006.499828] ipv6_list_rcv+0x112/0x140 Aug 7 07:26:16 rx [1006006.503748] __netif_receive_skb_list_core+0x1a4/0x250 Aug 7 07:26:16 rx [1006006.509057] netif_receive_skb_list_internal+0x1a1/0x2b0 Aug 7 07:26:16 rx [1006006.514538] gro_normal_list.part.0+0x1e/0x40 Aug 7 07:26:16 rx [1006006.519068] napi_complete_done+0x91/0x130 Aug 7 07:26:16 rx [1006006.523352] mlx5e_napi_poll+0x18e/0x610 [mlx5_core] Aug 7 07:26:16 rx [1006006.528481] net_rx_action+0x142/0x390 Aug 7 07:26:16 rx [1006006.532398] __do_softirq+0xd1/0x2c1 Aug 7 07:26:16 rx [1006006.536142] irq_exit+0xae/0xb0 Aug 7 07:26:16 rx [1006006.539452] do_IRQ+0x5a/0xf0 Aug 7 07:26:16 rx [1006006.542590] common_interrupt+0xf/0xf Aug 7 07:26:16 rx [1006006.546421] Aug 7 07:26:16 rx [1006006.548695] RIP: 0010:native_safe_halt+0xe/0x10 Aug 7 07:26:16 rx [1006006.553399] Code: 7b ff ff ff eb bd 90 90 90 90 90 90 e9 07 00 00 00 0f 00 2d 36 2c 50 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d 26 2c 50 00 fb f4 90 0f 1f 44 00 00 55 48 89 e5 41 55 41 54 53 e8 dd 5e 61 ff 65 Aug 7 07:26:16 rx [1006006.572309] RSP: 0018:ffffb42600177e70 EFLAGS: 00000246 ORIG_RAX: ffffffffffffffc2 Aug 7 07:26:16 rx [1006006.580040] RAX: ffffffff8ed08b20 RBX: 0000000000000005 RCX: 0000000000000001 Aug 7 07:26:16 rx [1006006.587337] RDX: 00000000f48eeca2 RSI: 0000000000000082 RDI: 0000000000000082 Aug 7 07:26:16 rx [1006006.594635] RBP: ffffb42600177e90 R08: 0000000000000000 R09: 000000000000020f Aug 7 07:26:16 rx [1006006.601931] R10: 0000000000100000 R11: 0000000000000000 R12: 0000000000000005 Aug 7 07:26:16 rx [1006006.609229] R13: ffff93157deb5f00 R14: 0000000000000000 R15: 0000000000000000 Aug 7 07:26:16 rx [1006006.616530] ? __cpuidle_text_start+0x8/0x8 Aug 7 07:26:16 rx [1006006.620886] ? default_idle+0x20/0x140 Aug 7 07:26:16 rx [1006006.624804] arch_cpu_idle+0x15/0x20 Aug 7 07:26:16 rx [1006006.628545] default_idle_call+0x23/0x30 Aug 7 07:26:16 rx [1006006.632640] do_idle+0x1fb/0x270 Aug 7 07:26:16 rx [1006006.636035] cpu_startup_entry+0x20/0x30 Aug 7 07:26:16 rx [1006006.640126] start_secondary+0x178/0x1d0 Aug 7 07:26:16 rx [1006006.644218] secondary_startup_64+0xa4/0xb0 Aug 7 07:26:17 rx [1006006.648568] Modules linked in: vrf bridge stp llc vxlan ip6_udp_tunnel udp_tunnel nls_iso8859_1 nft_ct amd64_edac_mod edac_mce_amd kvm_amd kvm crct10dif_pclmul ghash_clmulni_intel aesni_intel crypto_simd cryptd glue_helper wmi_bmof ipmi_ssif input_leds joydev rndis_host cdc_ether usbnet ast mii drm_vram_helper ttm drm_kms_helper i2c_algo_bit fb_sys_fops syscopyarea sysfillrect sysimgblt ccp mac_hid ipmi_si ipmi_devintf ipmi_msghandler sch_fq_codel nf_tables_set nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nf_tables nfnetlink ramoops reed_solomon efi_pstore drm ip_tables x_tables autofs4 raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c raid0 multipath linear mlx5_ib ib_uverbs ib_core raid1 hid_generic mlx5_core pci_hyperv_intf crc32_pclmul usbhid ahci tls mlxfw bnxt_en hid libahci nvme i2c_piix4 nvme_core wmi [last unloaded: cpuid] Aug 7 07:26:17 rx [1006006.726180] CR2: 0000000000000020 Aug 7 07:26:17 rx [1006006.729718] ---[ end trace e0e2e37e4e612984 ]--- Prior to seeing the first crash and on other machines we also see the warning in tcp_send_loss_probe() where packets_out is non-zero, but both transmit and retrans queues are empty so we know the box is seeing some accounting issue in this area: Jul 26 09:15:27 kernel: ------------[ cut here ]------------ Jul 26 09:15:27 kernel: invalid inflight: 2 state 1 cwnd 68 mss 8988 Jul 26 09:15:27 kernel: WARNING: CPU: 16 PID: 0 at net/ipv4/tcp_output.c:2605 tcp_send_loss_probe+0x214/0x220 Jul 26 09:15:27 kernel: Modules linked in: vrf bridge stp llc vxlan ip6_udp_tunnel udp_tunnel nls_iso8859_1 nft_ct amd64_edac_mod edac_mce_amd kvm_amd kvm crct10dif_pclmul ghash_clmulni_intel aesni_intel crypto_simd cryptd glue_helper wmi_bmof ipmi_ssif joydev input_leds rndis_host cdc_ether usbnet mii ast drm_vram_helper ttm drm_kms_he> Jul 26 09:15:27 kernel: CPU: 16 PID: 0 Comm: swapper/16 Not tainted 5.4.0-174-generic #193-Ubuntu Jul 26 09:15:27 kernel: Hardware name: Supermicro SMC 2x26 os-gen8 64C NVME-Y 256G/H12SSW-NTR, BIOS 2.5.V1.2U.NVMe.UEFI 05/09/2023 Jul 26 09:15:27 kernel: RIP: 0010:tcp_send_loss_probe+0x214/0x220 Jul 26 09:15:27 kernel: Code: 08 26 01 00 75 e2 41 0f b6 54 24 12 41 8b 8c 24 c0 06 00 00 45 89 f0 48 c7 c7 e0 b4 20 a7 c6 05 8d 08 26 01 01 e8 4a c0 0f 00 <0f> 0b eb ba 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 55 48 89 e5 41 Jul 26 09:15:27 kernel: RSP: 0018:ffffb7838088ce00 EFLAGS: 00010286 Jul 26 09:15:27 kernel: RAX: 0000000000000000 RBX: ffff9b84b5630430 RCX: 0000000000000006 Jul 26 09:15:27 kernel: RDX: 0000000000000007 RSI: 0000000000000096 RDI: ffff9b8e4621c8c0 Jul 26 09:15:27 kernel: RBP: ffffb7838088ce18 R08: 0000000000000927 R09: 0000000000000004 Jul 26 09:15:27 kernel: R10: 0000000000000000 R11: 0000000000000001 R12: ffff9b84b5630000 Jul 26 09:15:27 kernel: R13: 0000000000000000 R14: 000000000000231c R15: ffff9b84b5630430 Jul 26 09:15:27 kernel: FS: 0000000000000000(0000) GS:ffff9b8e46200000(0000) knlGS:0000000000000000 Jul 26 09:15:27 kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 Jul 26 09:15:27 kernel: CR2: 000056238cec2380 CR3: 0000003e49ede005 CR4: 0000000000760ee0 Jul 26 09:15:27 kernel: PKRU: 55555554 Jul 26 09:15:27 kernel: Call Trace: Jul 26 09:15:27 kernel: <IRQ> Jul 26 09:15:27 kernel: ? show_regs.cold+0x1a/0x1f Jul 26 09:15:27 kernel: ? __warn+0x98/0xe0 Jul 26 09:15:27 kernel: ? tcp_send_loss_probe+0x214/0x220 Jul 26 09:15:27 kernel: ? report_bug+0xd1/0x100 Jul 26 09:15:27 kernel: ? do_error_trap+0x9b/0xc0 Jul 26 09:15:27 kernel: ? do_invalid_op+0x3c/0x50 Jul 26 09:15:27 kernel: ? tcp_send_loss_probe+0x214/0x220 Jul 26 09:15:27 kernel: ? invalid_op+0x1e/0x30 Jul 26 09:15:27 kernel: ? tcp_send_loss_probe+0x214/0x220 Jul 26 09:15:27 kernel: tcp_write_timer_handler+0x1b4/0x240 Jul 26 09:15:27 kernel: tcp_write_timer+0x9e/0xe0 Jul 26 09:15:27 kernel: ? tcp_write_timer_handler+0x240/0x240 Jul 26 09:15:27 kernel: call_timer_fn+0x32/0x130 Jul 26 09:15:27 kernel: __run_timers.part.0+0x180/0x280 Jul 26 09:15:27 kernel: ? timerqueue_add+0x9b/0xb0 Jul 26 09:15:27 kernel: ? enqueue_hrtimer+0x3d/0x90 Jul 26 09:15:27 kernel: ? do_error_trap+0x9b/0xc0 Jul 26 09:15:27 kernel: ? do_invalid_op+0x3c/0x50 Jul 26 09:15:27 kernel: ? tcp_send_loss_probe+0x214/0x220 Jul 26 09:15:27 kernel: ? invalid_op+0x1e/0x30 Jul 26 09:15:27 kernel: ? tcp_send_loss_probe+0x214/0x220 Jul 26 09:15:27 kernel: tcp_write_timer_handler+0x1b4/0x240 Jul 26 09:15:27 kernel: tcp_write_timer+0x9e/0xe0 Jul 26 09:15:27 kernel: ? tcp_write_timer_handler+0x240/0x240 Jul 26 09:15:27 kernel: call_timer_fn+0x32/0x130 Jul 26 09:15:27 kernel: __run_timers.part.0+0x180/0x280 Jul 26 09:15:27 kernel: ? timerqueue_add+0x9b/0xb0 Jul 26 09:15:27 kernel: ? enqueue_hrtimer+0x3d/0x90 Jul 26 09:15:27 kernel: ? recalibrate_cpu_khz+0x10/0x10 Jul 26 09:15:27 kernel: ? ktime_get+0x3e/0xa0 Jul 26 09:15:27 kernel: ? native_x2apic_icr_write+0x30/0x30 Jul 26 09:15:27 kernel: run_timer_softirq+0x2a/0x50 Jul 26 09:15:27 kernel: __do_softirq+0xd1/0x2c1 Jul 26 09:15:27 kernel: irq_exit+0xae/0xb0 Jul 26 09:15:27 kernel: smp_apic_timer_interrupt+0x7b/0x140 Jul 26 09:15:27 kernel: apic_timer_interrupt+0xf/0x20 Jul 26 09:15:27 kernel: </IRQ> Jul 26 09:15:27 kernel: RIP: 0010:native_safe_halt+0xe/0x10 Jul 26 09:15:27 kernel: Code: 7b ff ff ff eb bd 90 90 90 90 90 90 e9 07 00 00 00 0f 00 2d 36 2c 50 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d 26 2c 50 00 fb f4 <c3> 90 0f 1f 44 00 00 55 48 89 e5 41 55 41 54 53 e8 dd 5e 61 ff 65 Jul 26 09:15:27 kernel: RSP: 0018:ffffb783801cfe70 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 Jul 26 09:15:27 kernel: RAX: ffffffffa6908b20 RBX: 0000000000000010 RCX: 0000000000000001 Jul 26 09:15:27 kernel: RDX: 000000006fc0c97e RSI: 0000000000000082 RDI: 0000000000000082 Jul 26 09:15:27 kernel: RBP: ffffb783801cfe90 R08: 0000000000000000 R09: 0000000000000225 Jul 26 09:15:27 kernel: R10: 0000000000100000 R11: 0000000000000000 R12: 0000000000000010 Jul 26 09:15:27 kernel: R13: ffff9b8e390b0000 R14: 0000000000000000 R15: 0000000000000000 Jul 26 09:15:27 kernel: ? __cpuidle_text_start+0x8/0x8 Jul 26 09:15:27 kernel: ? default_idle+0x20/0x140 Jul 26 09:15:27 kernel: arch_cpu_idle+0x15/0x20 Jul 26 09:15:27 kernel: default_idle_call+0x23/0x30 Jul 26 09:15:27 kernel: do_idle+0x1fb/0x270 Jul 26 09:15:27 kernel: cpu_startup_entry+0x20/0x30 Jul 26 09:15:27 kernel: start_secondary+0x178/0x1d0 Jul 26 09:15:27 kernel: secondary_startup_64+0xa4/0xb0 Jul 26 09:15:27 kernel: ---[ end trace e7ac822987e33be1 ]--- The NULL ptr deref is coming from tcp_rto_delta_us() attempting to pull an skb off the head of the retransmit queue and then dereferencing that skb to get the skb_mstamp_ns value via tcp_skb_timestamp_us(skb). The crash is the same one that was reported a # of years ago here: https://lore.kernel.org/netdev/86c0f836-9a7c-438b-d81a-839be45f1f58@gmail.com/T/#t and the kernel we're running has the fix which was added to resolve this issue. Unfortunately we've been unsuccessful so far in reproducing this problem in the lab and do not have the luxury of pushing out a new kernel to try and test if newer kernels resolve this issue at the moment. I realize this is a report against both an Ubuntu kernel and also an older 5.4 kernel. I have reported this issue to Ubuntu here: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2077657 however I feel like since this issue has possibly cropped up again it makes sense to build in some protection in this path (even on the latest kernel versions) since the code in question just blindly assumes there's a valid skb without testing if it's NULL b/f it looks at the timestamp. Given we have seen crashes in this path before and now this case it seems like we should protect ourselves for when packets_out accounting is incorrect. While we should fix that root cause we should also just make sure the skb is not NULL before dereferencing it. Also add a warn once here to capture some information if/when the problem case is hit again. Fixes: e1a10ef7fa87 ("tcp: introduce tcp_rto_delta_us() helper for xmit timer fix") Signed-off-by: Josh Hunt <johunt@akamai.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2024-09-11net: add support for skbs with unreadable fragsMina Almasry1-1/+2
For device memory TCP, we expect the skb headers to be available in host memory for access, and we expect the skb frags to be in device memory and unaccessible to the host. We expect there to be no mixing and matching of device memory frags (unaccessible) with host memory frags (accessible) in the same skb. Add a skb->devmem flag which indicates whether the frags in this skb are device memory frags or not. __skb_fill_netmem_desc() now checks frags added to skbs for net_iov, and marks the skb as skb->devmem accordingly. Add checks through the network stack to avoid accessing the frags of devmem skbs and avoid coalescing devmem skbs with non devmem skbs. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Link: https://patch.msgid.link/20240910171458.219195-9-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>