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authorSven Schnelle <svens@linux.ibm.com>2021-06-11 10:27:51 +0200
committerVasily Gorbik <gor@linux.ibm.com>2021-06-21 11:19:18 +0200
commitfc66127dc3396338f287c3b494dfbf102547e770 (patch)
tree5c18d8af2e864a4251bb9f33983c18cd53ffcfea
parent13311e74253fe64329390df80bed3f07314ddd61 (diff)
s390: fix system call restart with multiple signals
glibc complained with "The futex facility returned an unexpected error code.". It turned out that the futex syscall returned -ERESTARTSYS because a signal is pending. arch_do_signal_or_restart() restored the syscall parameters (nameley regs->gprs[2]) and set PIF_SYSCALL_RESTART. When another signal is made pending later in the exit loop arch_do_signal_or_restart() is called again. This function clears PIF_SYSCALL_RESTART and checks the return code which is set in regs->gprs[2]. However, regs->gprs[2] was restored in the previous run and no longer contains -ERESTARTSYS, so PIF_SYSCALL_RESTART isn't set again and the syscall is skipped. Fix this by not clearing PIF_SYSCALL_RESTART - it is already cleared in __do_syscall() when the syscall is restarted. Reported-by: Bjoern Walk <bwalk@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Fixes: 56e62a737028 ("s390: convert to generic entry") Cc: <stable@vger.kernel.org> # 5.12 Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
-rw-r--r--arch/s390/kernel/signal.c1
1 files changed, 0 insertions, 1 deletions
diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c
index 90163e6184f5..080e7aed181f 100644
--- a/arch/s390/kernel/signal.c
+++ b/arch/s390/kernel/signal.c
@@ -512,7 +512,6 @@ void arch_do_signal_or_restart(struct pt_regs *regs, bool has_signal)
/* No handlers present - check for system call restart */
clear_pt_regs_flag(regs, PIF_SYSCALL);
- clear_pt_regs_flag(regs, PIF_SYSCALL_RESTART);
if (current->thread.system_call) {
regs->int_code = current->thread.system_call;
switch (regs->gprs[2]) {