From: Jens Axboe <axboe@kernel.dk>
Date: Mon, 22 Mar 2021 15:39:12 +0000 (-0600)
Subject: kernel: allow fork with TIF_NOTIFY_SIGNAL pending
X-Git-Tag: v5.10.162~17
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0f735cf52bd0b2aaca865e3d2e3dc276479e41ba;p=thirdparty%2Fkernel%2Fstable.git

kernel: allow fork with TIF_NOTIFY_SIGNAL pending

[ Upstream commit 66ae0d1e2d9fe6ec70e73fcfdcf4b390e271c1ac ]

fork() fails if signal_pending() is true, but there are two conditions
that can lead to that:

1) An actual signal is pending. We want fork to fail for that one, like
   we always have.

2) TIF_NOTIFY_SIGNAL is pending, because the task has pending task_work.
   We don't need to make it fail for that case.

Allow fork() to proceed if just task_work is pending, by changing the
signal_pending() check to task_sigpending().

Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/kernel/fork.c b/kernel/fork.c
index 252a40f14f726..b5cd5cdd3e678 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1942,7 +1942,7 @@ static __latent_entropy struct task_struct *copy_process(
 	recalc_sigpending();
 	spin_unlock_irq(&current->sighand->siglock);
 	retval = -ERESTARTNOINTR;
-	if (signal_pending(current))
+	if (task_sigpending(current))
 		goto fork_out;
 
 	retval = -ENOMEM;