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puranjaymohanAlexei Starovoitov
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bpf: Send signals asynchronously if !preemptible
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: 1bc7896 ("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>
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kernel/trace/bpf_trace.c

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -842,7 +842,7 @@ static int bpf_send_signal_common(u32 sig, enum pid_type type, struct task_struc
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if (unlikely(is_global_init(task)))
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return -EPERM;
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if (irqs_disabled()) {
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if (!preemptible()) {
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/* Do an early check on signal validity. Otherwise,
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* the error is lost in deferred irq_work.
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*/

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