From: Eric W. Biederman ebiederm@xmission.com
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@linux.ibm.com Cc: Vasily Gorbik gor@linux.ibm.com Cc: Christian Borntraeger borntraeger@de.ibm.com Cc: linux-s390@vger.kernel.org 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@de.ibm.com Link: https://lkml.kernel.org/r/20211020174406.17889-11-ebiederm@xmission.com Signed-off-by: Eric W. Biederman ebiederm@xmission.com Cc: Thomas Backlund tmb@iki.fi Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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"); }