This is a note to let you know that I've just added the patch titled
signal/s390: Use force_sigsegv in default_trap_handler
to the 5.15-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:
signal-s390-use-force_sigsegv-in-default_trap_handler.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 9bc508cf0791c8e5a37696de1a046d746fcbd9d8 Mon Sep 17 00:00:00 2001
From: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Date: Wed, 20 Oct 2021 12:43:57 -0500
Subject: signal/s390: Use force_sigsegv in default_trap_handler
From: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
commit 9bc508cf0791c8e5a37696de1a046d746fcbd9d8 upstream.
Reading the history it is unclear why default_trap_handler calls
do_exit. It is not even menthioned in the commit where the change
happened. My best guess is that because it is unknown why the
exception happened it was desired to guarantee the process never
returned to userspace.
Using do_exit(SIGSEGV) has the problem that it will only terminate one
thread of a process, leaving the process in an undefined state.
Use force_sigsegv(SIGSEGV) instead which effectively has the same
behavior except that is uses the ordinary signal mechanism and
terminates all threads of a process and is generally well defined.
Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Cc: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Cc: linux-s390@xxxxxxxxxxxxxxx
Fixes: ca2ab03237ec ("[PATCH] s390: core changes")
History Tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git
Reviewed-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20211020174406.17889-11-ebiederm@xxxxxxxxxxxx
Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Thomas Backlund <tmb@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/s390/kernel/traps.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/s390/kernel/traps.c
+++ b/arch/s390/kernel/traps.c
@@ -84,7 +84,7 @@ static void default_trap_handler(struct
{
if (user_mode(regs)) {
report_user_fault(regs, SIGSEGV, 0);
- do_exit(SIGSEGV);
+ force_sigsegv(SIGSEGV);
} else
die(regs, "Unknown program exception");
}
Patches currently in stable-queue which might be from ebiederm@xxxxxxxxxxxx are
queue-5.15/signal-vm86_32-properly-send-sigsegv-when-the-vm86-state-cannot-be-saved.patch
queue-5.15/signal-don-t-always-set-sa_immutable-for-forced-signals.patch
queue-5.15/signal-x86-in-emulate_vsyscall-force-a-signal-instead-of-calling-do_exit.patch
queue-5.15/ipc-warn-if-trying-to-remove-ipc-object-which-is-absent.patch
queue-5.15/signal-replace-force_sigsegv-sigsegv-with-force_fatal_sig-sigsegv.patch
queue-5.15/signal-powerpc-on-swapcontext-failure-force-sigsegv.patch
queue-5.15/exit-syscall_user_dispatch-send-ordinary-signals-on-failure.patch
queue-5.15/signal-s390-use-force_sigsegv-in-default_trap_handler.patch
queue-5.15/signal-implement-force_fatal_sig.patch
queue-5.15/signal-sparc32-in-setup_rt_frame-and-setup_fram-use-force_fatal_sig.patch
queue-5.15/signal-sparc32-exit-with-a-fatal-signal-when-try_to_clear_window_buffer-fails.patch
queue-5.15/shm-extend-forced-shm-destroy-to-support-objects-from-several-ipc-nses.patch
queue-5.15/signal-replace-force_fatal_sig-with-force_exit_sig-when-in-doubt.patch
