linux-kernel - Re: [PATCH] s390: add support for TIF_NOTIFY

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Date:   Mon, 2 Nov 2020 10:07:33 -0700
From:   Jens Axboe <axboe@...nel.dk>
To:     Qian Cai <cai@...hat.com>
Cc:     linux-s390@...r.kernel.org, Heiko Carstens <hca@...ux.ibm.com>,
        linux-kernel@...r.kernel.org, peterz@...radead.org,
        oleg@...hat.com, tglx@...utronix.de,
        Stephen Rothwell <sfr@...b.auug.org.au>,
        Linux-Next Mailing List <linux-next@...r.kernel.org>
Subject: Re: [PATCH] s390: add support for TIF_NOTIFY_SIGNAL

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: linux-s390@...r.kernel.org
>>> Signed-off-by: Jens Axboe <axboe@...nel.dk>
> 
> 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