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bpf: Send signals asynchronously if !preemptible

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[ Upstream commit 87c544108b612512b254c8f79aa5c0a8546e2cc4 ]

BPF programs can execute in all kinds of contexts and when a program
running in a non-preemptible context uses the bpf_send_signal() kfunc,
it will cause issues because this kfunc can sleep.
Change `irqs_disabled()` to `!preemptible()`.

Reported-by: syzbot+97da3d7e0112d59971de@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/67486b09.050a0220.253251.0084.GAE@google.com/
Fixes: 1bc7896e9e ("bpf: Fix deadlock with rq_lock in bpf_send_signal()")
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20250115103647.38487-1-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Puranjay Mohan 2025-01-15 10:36:47 +00:00 committed by Greg Kroah-Hartman
parent db7b15a67f
commit be42a09fe8
1 changed files with 1 additions and 1 deletions
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2
kernel/trace/bpf_trace.c
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@ -857,7 +857,7 @@ static int bpf_send_signal_common(u32 sig, enum pid_type type)
if (unlikely(is_global_init(current)))
return -EPERM;
if (irqs_disabled()) {
if (!preemptible()) {
/* Do an early check on signal validity. Otherwise,
* the error is lost in deferred irq_work.
*/