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| author | Yonghong Song <yonghong.song@linux.dev> | 2025-07-03 07:11:17 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2025-07-03 19:31:30 -0700 |
| commit | 82bc4abf28d8147dd5da9ba52f0aa1bac23c125e (patch) | |
| tree | 71b23ffbe8482b3edd886d34025022b164df8a01 /kernel | |
| parent | bpf: Reduce stack frame size by using env->insn_buf for bpf insns (diff) | |
| download | linux-82bc4abf28d8147dd5da9ba52f0aa1bac23c125e.tar.gz linux-82bc4abf28d8147dd5da9ba52f0aa1bac23c125e.zip | |
bpf: Avoid putting struct bpf_scc_callchain variables on the stack
Add a 'struct bpf_scc_callchain callchain_buf' field in bpf_verifier_env.
This way, the previous bpf_scc_callchain local variables can be
replaced by taking address of env->callchain_buf. This can reduce stack
usage and fix the following error:
kernel/bpf/verifier.c:19921:12: error: stack frame size (1368) exceeds limit (1280) in 'do_check'
[-Werror,-Wframe-larger-than]
Reported-by: Arnd Bergmann <arnd@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20250703141117.1485108-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/verifier.c | 36 |
1 files changed, 18 insertions, 18 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 92dba3c9664f..0f6cc2275695 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1914,19 +1914,19 @@ static char *format_callchain(struct bpf_verifier_env *env, struct bpf_scc_callc */ static int maybe_enter_scc(struct bpf_verifier_env *env, struct bpf_verifier_state *st) { - struct bpf_scc_callchain callchain; + struct bpf_scc_callchain *callchain = &env->callchain_buf; struct bpf_scc_visit *visit; - if (!compute_scc_callchain(env, st, &callchain)) + if (!compute_scc_callchain(env, st, callchain)) return 0; - visit = scc_visit_lookup(env, &callchain); - visit = visit ?: scc_visit_alloc(env, &callchain); + visit = scc_visit_lookup(env, callchain); + visit = visit ?: scc_visit_alloc(env, callchain); if (!visit) return -ENOMEM; if (!visit->entry_state) { visit->entry_state = st; if (env->log.level & BPF_LOG_LEVEL2) - verbose(env, "SCC enter %s\n", format_callchain(env, &callchain)); + verbose(env, "SCC enter %s\n", format_callchain(env, callchain)); } return 0; } @@ -1939,21 +1939,21 @@ static int propagate_backedges(struct bpf_verifier_env *env, struct bpf_scc_visi */ static int maybe_exit_scc(struct bpf_verifier_env *env, struct bpf_verifier_state *st) { - struct bpf_scc_callchain callchain; + struct bpf_scc_callchain *callchain = &env->callchain_buf; struct bpf_scc_visit *visit; - if (!compute_scc_callchain(env, st, &callchain)) + if (!compute_scc_callchain(env, st, callchain)) return 0; - visit = scc_visit_lookup(env, &callchain); + visit = scc_visit_lookup(env, callchain); if (!visit) { verifier_bug(env, "scc exit: no visit info for call chain %s", - format_callchain(env, &callchain)); + format_callchain(env, callchain)); return -EFAULT; } if (visit->entry_state != st) return 0; if (env->log.level & BPF_LOG_LEVEL2) - verbose(env, "SCC exit %s\n", format_callchain(env, &callchain)); + verbose(env, "SCC exit %s\n", format_callchain(env, callchain)); visit->entry_state = NULL; env->num_backedges -= visit->num_backedges; visit->num_backedges = 0; @@ -1968,22 +1968,22 @@ static int add_scc_backedge(struct bpf_verifier_env *env, struct bpf_verifier_state *st, struct bpf_scc_backedge *backedge) { - struct bpf_scc_callchain callchain; + struct bpf_scc_callchain *callchain = &env->callchain_buf; struct bpf_scc_visit *visit; - if (!compute_scc_callchain(env, st, &callchain)) { + if (!compute_scc_callchain(env, st, callchain)) { verifier_bug(env, "add backedge: no SCC in verification path, insn_idx %d", st->insn_idx); return -EFAULT; } - visit = scc_visit_lookup(env, &callchain); + visit = scc_visit_lookup(env, callchain); if (!visit) { verifier_bug(env, "add backedge: no visit info for call chain %s", - format_callchain(env, &callchain)); + format_callchain(env, callchain)); return -EFAULT; } if (env->log.level & BPF_LOG_LEVEL2) - verbose(env, "SCC backedge %s\n", format_callchain(env, &callchain)); + verbose(env, "SCC backedge %s\n", format_callchain(env, callchain)); backedge->next = visit->backedges; visit->backedges = backedge; visit->num_backedges++; @@ -1999,12 +1999,12 @@ static int add_scc_backedge(struct bpf_verifier_env *env, static bool incomplete_read_marks(struct bpf_verifier_env *env, struct bpf_verifier_state *st) { - struct bpf_scc_callchain callchain; + struct bpf_scc_callchain *callchain = &env->callchain_buf; struct bpf_scc_visit *visit; - if (!compute_scc_callchain(env, st, &callchain)) + if (!compute_scc_callchain(env, st, callchain)) return false; - visit = scc_visit_lookup(env, &callchain); + visit = scc_visit_lookup(env, callchain); if (!visit) return false; return !!visit->backedges; |