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 <stable@xxxxxxxxxxxxxxx> know about it.
>From sumanthk@xxxxxxxxxxxxx Fri Feb 17 15:04:16 2023
From: Sumanth Korikkar <sumanthk@xxxxxxxxxxxxx>
Date: Wed, 15 Feb 2023 15:13:24 +0100
Subject: [PATCH v2 1/1] s390/signal: fix endless loop in do_signal
To: stable@xxxxxxxxxxxxxxx, gregkh@xxxxxxxxxxxxxxxxxxx, debian-s390@xxxxxxxxxxxxxxxx, debian-kernel@xxxxxxxxxxxxxxxx
Cc: svens@xxxxxxxxxxxxx, hca@xxxxxxxxxxxxx, gor@xxxxxxxxxxxxx, sumanthk@xxxxxxxxxxxxx, Ulrich.Weigand@xxxxxxxxxx, dipak.zope1@xxxxxxx
Message-ID: <20230215141324.1239245-1-sumanthk@xxxxxxxxxxxxx>
From: Sumanth Korikkar <sumanthk@xxxxxxxxxxxxx>
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: stable@xxxxxxxxxxxxxxx # 5.10.162
Acked-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
Acked-by: Sven Schnelle <svens@xxxxxxxxxxxxx>
Signed-off-by: Sumanth Korikkar <sumanthk@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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 sumanthk@xxxxxxxxxxxxx are
queue-5.10/s390-signal-fix-endless-loop-in-do_signal.patch
