Patch "[PATCH v2 1/1] s390/signal: fix endless loop in do_signal" has been added to the 5.10-stable tree

This is a note to let you know that I've just added the patch titled

    [PATCH v2 1/1] s390/signal: fix endless loop in do_signal

to the 5.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     s390-signal-fix-endless-loop-in-do_signal.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From [email protected]  Fri Feb 17 15:04:16 2023
From: Sumanth Korikkar <[email protected]>
Date: Wed, 15 Feb 2023 15:13:24 +0100
Subject: [PATCH v2 1/1] s390/signal: fix endless loop in do_signal
To: [email protected], [email protected], [email protected], [email protected]
Cc: [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]
Message-ID: <[email protected]>

From: Sumanth Korikkar <[email protected]>

No upstream commit exists: the problem addressed here is that 'commit
75309018a24d ("s390: add support for TIF_NOTIFY_SIGNAL")' was backported
to 5.10. This commit is broken, but nobody noticed upstream, since
shortly after s390 converted to generic entry with 'commit 56e62a737028
("s390: convert to generic entry")', which implicitly fixed the problem
outlined below.

Thread flag is set to TIF_NOTIFY_SIGNAL for io_uring work.  The io work
user or syscall calls do_signal when either one of the TIF_SIGPENDING or
TIF_NOTIFY_SIGNAL flag is set.  However, do_signal does consider only
TIF_SIGPENDING signal and ignores TIF_NOTIFY_SIGNAL condition.  This
means get_signal is never invoked  for TIF_NOTIFY_SIGNAL and hence the
flag is not cleared, which results in an endless do_signal loop.

Reference: 'commit 788d0824269b ("io_uring: import 5.15-stable io_uring")'
Fixes: 75309018a24d ("s390: add support for TIF_NOTIFY_SIGNAL")
Cc: [email protected]  # 5.10.162
Acked-by: Heiko Carstens <[email protected]>
Acked-by: Sven Schnelle <[email protected]>
Signed-off-by: Sumanth Korikkar <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 arch/s390/kernel/signal.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/s390/kernel/signal.c
+++ b/arch/s390/kernel/signal.c
@@ -472,7 +472,7 @@ void do_signal(struct pt_regs *regs)
 	current->thread.system_call =
 		test_pt_regs_flag(regs, PIF_SYSCALL) ? regs->int_code : 0;
 
-	if (test_thread_flag(TIF_SIGPENDING) && get_signal(&ksig)) {
+	if (get_signal(&ksig)) {
 		/* Whee!  Actually deliver the signal.  */
 		if (current->thread.system_call) {
 			regs->int_code = current->thread.system_call;


Patches currently in stable-queue which might be from [email protected] are

queue-5.10/s390-signal-fix-endless-loop-in-do_signal.patch