Re: [syzbot] [io-uring?] WARNING in __secure_computing

[Oleg Nesterov <oleg@redhat.com>]

On 02/17, syzbot wrote:
>
> WARNING: kernel/seccomp.c:1407 at __secure_computing+0x2ae/0x2e0 kernel/seccomp.c:1407, CPU#1: syz.0.17/6077

#syz test

So signalfd_dequeue() is called by get_signal() -> task_work_run(), the work
was queued by io_uring... Thanks Kusaram.

Obviously this is not the right fix (and we should not blame io_uring), but
lets test to ensure.

Oleg.
---

diff --git a/fs/signalfd.c b/fs/signalfd.c
index dff53745e352..8819dea943f8 100644
--- a/fs/signalfd.c
+++ b/fs/signalfd.c
@@ -158,6 +158,9 @@ static ssize_t signalfd_dequeue(struct signalfd_ctx *ctx, kernel_siginfo_t *info
 	ssize_t ret;
 	DECLARE_WAITQUEUE(wait, current);
 
+	if (current->seccomp.mode == SECCOMP_MODE_FILTER + 1) // SECCOMP_MODE_DEAD
+		return -EINTR;
+
 	spin_lock_irq(&current->sighand->siglock);
 	ret = dequeue_signal(&ctx->sigmask, info, &type);
 	switch (ret) {