diff options
| author | Xu Xin <xu.xin16@zte.com.cn> | 2026-07-29 14:11:59 +0800 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2026-07-30 16:29:03 -0700 |
| commit | f0e80dee4e32fd11e6ee1b714b75f681c7cafd3e (patch) | |
| tree | 9e311b9cd8ecdba62475b6a60f8f264769317027 /kernel | |
| parent | 863f3ddd0b8ac65abfb50d3be0869268ac0e277b (diff) | |
bpf: Log error code on trampoline unlink failure
Replace silent WARN_ON_ONCE with WARN_ONCE that prints the actual error
code from bpf_trampoline_unlink_prog(). This aids debugging of race
conditions during link teardown, while keeping the warning rate limited
to avoid log flooding.
This will be very helpful for speeding up trouble-shooting of some crash
UAF due to bpf_trampoline_unlink_prog failures.
No change to unlink behavior.
Signed-off-by: Xu Xin <xu.xin16@zte.com.cn>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Acked-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/bpf/20260729141159128mEJmS_aujBKr-cBu1p_UI@zte.com.cn
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/syscall.c | 8 | ||||
| -rw-r--r-- | kernel/bpf/trampoline.c | 12 |
2 files changed, 13 insertions, 7 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 0eb43ba76a8a..94091130bcc5 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3555,10 +3555,12 @@ static void bpf_tracing_link_release(struct bpf_link *link) { struct bpf_tracing_link *tr_link = container_of(link, struct bpf_tracing_link, link.link); + int err; - WARN_ON_ONCE(bpf_trampoline_unlink_prog(&tr_link->link.node, - tr_link->trampoline, - tr_link->tgt_prog)); + err = bpf_trampoline_unlink_prog(&tr_link->link.node, + tr_link->trampoline, + tr_link->tgt_prog); + WARN_ONCE(err, "bpf_trampoline_unlink_prog failed: %d\n", err); bpf_trampoline_put(tr_link->trampoline); diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c index 129d07db117e..ed7999ad6c66 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -1004,12 +1004,15 @@ static void bpf_shim_tramp_link_release(struct bpf_link *link) { struct bpf_shim_tramp_link *shim_link = container_of(link, struct bpf_shim_tramp_link, link.link); + int err; /* paired with 'shim_link->trampoline = tr' in bpf_trampoline_link_cgroup_shim */ if (!shim_link->trampoline) return; - WARN_ON_ONCE(bpf_trampoline_unlink_prog(&shim_link->link.node, shim_link->trampoline, NULL)); + err = bpf_trampoline_unlink_prog(&shim_link->link.node, shim_link->trampoline, NULL); + WARN_ONCE(err, "bpf_trampoline_unlink_prog failed: %d\n", err); + bpf_trampoline_put(shim_link->trampoline); } @@ -1720,15 +1723,16 @@ int bpf_trampoline_multi_detach(struct bpf_prog *prog, struct bpf_tracing_multi_ { struct bpf_tracing_multi_data *data = &link->data; struct bpf_tracing_multi_node *mnode; - int i; + int i, err; trampoline_lock_all(); for_each_mnode(mnode, link) { data->entry = &mnode->entry; bpf_trampoline_multi_attach_init(mnode->trampoline); - WARN_ON_ONCE(__bpf_trampoline_unlink_prog(&mnode->node, mnode->trampoline, - NULL, &trampoline_multi_ops, data)); + err = __bpf_trampoline_unlink_prog(&mnode->node, mnode->trampoline, NULL, + &trampoline_multi_ops, data); + WARN_ONCE(err, "__bpf_trampoline_unlink_prog failed: %d\n", err); } if (ftrace_hash_count(data->unreg)) |