Subject: Re: [PATCH] s390: add support for TIF_NOTIFY_SIGNAL

From: Jens Axboe <[email-masked]>
Date: Mon, 2 Nov 2020 10:07:33 -0700

On 11/2/20 9:59 AM, Qian Cai wrote:
> On Sun, 2020-11-01 at 17:31 +0000, Heiko Carstens wrote:
>> On Thu, Oct 29, 2020 at 10:21:11AM -0600, Jens Axboe wrote:
>>> Wire up TIF_NOTIFY_SIGNAL handling for s390.
>>>
>>> Cc: [email-masked]
>>> Signed-off-by: Jens Axboe <[email-masked]>
> 
> Even though I did confirm that today's linux-next contains this additional patch
> from Heiko below, a z10 guest is still unable to boot. Reverting the whole
> series (reverting only "s390: add support for TIF_NOTIFY_SIGNAL" introduced
> compiling errors) fixed the problem, i.e., git revert --no-edit
> af0dd809f3d3..7b074c15374c [1]

That's odd, it should build fine without that patch. How did it fail for you?

Can you try and add this on top? Looks like I forgot the signal change for
s390, though that shouldn't really cause any issues.

diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c
index 9e900a8977bd..a68c3796a1bf 100644
--- 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 (get_signal(&ksig)) {
+	if (test_thread_flag(TIF_NOTIFY_SIGNAL) && get_signal(&ksig)) {
 		/* Whee!  Actually deliver the signal.  */
 		if (current->thread.system_call) {
 			regs->int_code = current->thread.system_call;

-- 
Jens Axboe