From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Kalle Valo <kvalo@kernel.org>
Cc: Dave Hansen <dave.hansen@intel.com>,
Borislav Petkov <bp@alien8.de>,
Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
"Rafael J. Wysocki" <rafael@kernel.org>,
x86@kernel.org, linux-pm@vger.kernel.org,
linux-kernel@vger.kernel.org, regressions@lists.linux.dev,
Jeff Johnson <quic_jjohnson@quicinc.com>
Subject: Re: [regression] suspend stress test stalls within 30 minutes
Date: Fri, 17 May 2024 21:08:40 +0200 [thread overview]
Message-ID: <CAJZ5v0hJnXPMq5cjEs=yPrSU1hpJ3H3cMce8fOGQCripYfbeGQ@mail.gmail.com> (raw)
In-Reply-To: <87eda0cljg.fsf@kernel.org>
On Fri, May 17, 2024 at 8:59 PM Kalle Valo <kvalo@kernel.org> wrote:
>
> Dave Hansen <dave.hansen@intel.com> writes:
>
> > On 5/17/24 11:37, Kalle Valo wrote:
> >> While writing this email I found another way to continue the suspend
> >> after a stall: terminate rtcwake with CTRL-C in the ssh session running
> >> the for loop. That explains why 'sudo shutdown -h now' makes the suspend
> >> go forward, it most likely kills the stalled rtcwake process.
> >
> > Could we try and figure out what rtcwake is doing during its stall? A
> > couple of ideas:
> >
> > You could strace it to see if it's hung in the kernel:
> >
> > strace -o strace.log rtcwake ... <args here>
> >
> > You could look at its stack in /proc, like this:
> >
> > # cat /proc/`pidof sleep`/stack
> > [<0>] hrtimer_nanosleep+0xb5/0x190
> > [<0>] common_nsleep+0x44/0x50
> > [<0>] __x64_sys_clock_nanosleep+0xcb/0x140
> > [<0>] do_syscall_64+0x65/0x140
> > [<0>] entry_SYSCALL_64_after_hwframe+0x6e/0x76
> >
> > Or you can use sysrq:
> >
> > echo t > /proc/sysrq-trigger
> >
> > to get *all* tasks' stacks dumped out to dmesg.
> >
> > I'd probably do all three in that order.
> >
> > Getting a function-graph trace of rtcwake during the stall would also be
> > nice, but that's a lot of data so let's try the easier things first.
>
> I can do all that but most probably not this week. Luckily it's quite
> easy to reproduce the bug, one time I even saw it in the first iteration
> and usually within 15 minutes or so.
>
> And do let me know if there's anything else I should try.
My somewhat educated guess is that pm_notifier_call_chain_robust()
blocks for you, so you can add debug printk()s around the call to this
in suspend_prepare().
It is also possible that pm_prepare_console() does something weird and
your description of the problem indicates that it doesn't get to user
space freezing.
next prev parent reply other threads:[~2024-05-17 19:08 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-11 18:22 [regression] suspend stress test stalls within 30 minutes Kalle Valo
2024-05-11 18:48 ` Borislav Petkov
2024-05-11 18:49 ` Borislav Petkov
2024-05-11 20:26 ` Kalle Valo
2024-05-13 19:58 ` Kalle Valo
2024-05-14 13:17 ` Kalle Valo
2024-05-14 16:05 ` Borislav Petkov
2024-05-14 17:36 ` Pawan Gupta
2024-05-17 17:15 ` Kalle Valo
2024-05-17 17:22 ` Dave Hansen
2024-05-17 18:37 ` Kalle Valo
2024-05-17 18:48 ` Dave Hansen
2024-05-17 18:58 ` Kalle Valo
2024-05-17 19:08 ` Rafael J. Wysocki [this message]
2024-05-17 19:00 ` Rafael J. Wysocki
2024-05-22 1:52 ` Len Brown
2024-05-17 17:26 ` Borislav Petkov
2024-05-17 18:22 ` Kalle Valo
2024-05-14 16:10 ` Dave Hansen
2024-05-15 7:22 ` Pawan Gupta
2024-05-15 7:44 ` Borislav Petkov
2024-05-15 16:27 ` Pawan Gupta
2024-05-15 16:47 ` Kalle Valo
2024-05-16 7:03 ` Pawan Gupta
2024-05-16 14:25 ` Pawan Gupta
2024-05-16 14:32 ` Dave Hansen
2024-05-16 15:41 ` Pawan Gupta
2024-05-17 17:41 ` Kalle Valo
2024-05-17 18:31 ` Pawan Gupta
2024-05-17 17:23 ` Kalle Valo
2024-05-17 17:19 ` Kalle Valo
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