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| author | Jesper Dangaard Brouer <hawk@kernel.org> | 2025-07-16 18:26:53 +0200 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-07-18 16:59:05 -0700 |
| commit | a6f190630d070173897a7e98a30188b7638ba0a1 (patch) | |
| tree | 72e6fadd557f4929f49bca1fff592c1d34be0e3f /net/ipv4/udp.c | |
| parent | net: stream: add description for sk_stream_write_space() (diff) | |
| download | linux-a6f190630d070173897a7e98a30188b7638ba0a1.tar.gz linux-a6f190630d070173897a7e98a30188b7638ba0a1.zip | |
net: track pfmemalloc drops via SKB_DROP_REASON_PFMEMALLOC
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>
Diffstat (limited to 'net/ipv4/udp.c')
| -rw-r--r-- | net/ipv4/udp.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 49f43c54cfb0..cc3ce0f762ec 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -2347,7 +2347,7 @@ static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb) */ static int udp_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb) { - int drop_reason = SKB_DROP_REASON_NOT_SPECIFIED; + enum skb_drop_reason drop_reason = SKB_DROP_REASON_NOT_SPECIFIED; struct udp_sock *up = udp_sk(sk); int is_udplite = IS_UDPLITE(sk); @@ -2436,10 +2436,8 @@ static int udp_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb) udp_lib_checksum_complete(skb)) goto csum_error; - if (sk_filter_trim_cap(sk, skb, sizeof(struct udphdr))) { - drop_reason = SKB_DROP_REASON_SOCKET_FILTER; + if (sk_filter_trim_cap(sk, skb, sizeof(struct udphdr), &drop_reason)) goto drop; - } udp_csum_pull_header(skb); |