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Groups > linux.kernel > #1334729
| From | "Rafael J. Wysocki" <rafael@kernel.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' |
| Date | 2016-02-15 19:50 +0100 |
| Message-ID | <r2wnF-4Wo-47@gated-at.bofh.it> (permalink) |
| References | <r2uOU-3Y1-53@gated-at.bofh.it> <r2wnF-4Wo-45@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Mon, Feb 15, 2016 at 7:41 PM, Rafael J. Wysocki <rafael@kernel.org> wrote:
> On Mon, Feb 15, 2016 at 6:05 PM, Guenter Roeck <linux@roeck-us.net> wrote:
>> Rafael,
>
> Hi,
>
> Thanks for the report!
>
>> I see crashes in various arm qemu tests due to 'cpufreq: governor: Replace
>> timers with utilization update callbacks' with next-20160215. An example
>> crash log and bisect results are attached below.
>>
>> Please let me know if there is anything I can do to help tracking down
>> the problem.
>
> It looks like we've uncovered some nastiness in the arch ARM code (see below).
>
> [cut]
>
>> [ 1.340000] Unable to handle kernel NULL pointer dereference at virtual address 00000000
>> [ 1.340000] pgd = c0204000
>> [ 1.340000] [00000000] *pgd=00000000
>> [ 1.340000] Internal error: Oops: 80000005 [#1] SMP ARM
>> [ 1.340000] Modules linked in:
>> [ 1.340000] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.5.0-rc4-next-20160215 #1
>> [ 1.340000] Hardware name: Generic OMAP3-GP (Flattened Device Tree)
>> [ 1.340000] task: cb060000 ti: cb05a000 task.ti: cb05a000
>> [ 1.340000] PC is at 0x0
>> [ 1.340000] LR is at arch_send_call_function_single_ipi+0x34/0x38
>
> Since this is ARM, arch_send_call_function_single_ipi() looks like this:
>
> void arch_send_call_function_single_ipi(int cpu)
> {
> smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
> }
>
> so I'm not sure how the NULL pointer deref is possible even.
>
> The only thing coming to mind would be that cpumask_of(cpu) triggers
> this, but I'm not sure how exactly that can happen.
>
> I need help from somebody who knows how this low-level stuff works on ARM.
Well, could there be a problem with sending an IPI to the same CPU
that's sending it?
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Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' Guenter Roeck <linux@roeck-us.net> - 2016-02-15 18:10 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' "Rafael J. Wysocki" <rafael@kernel.org> - 2016-02-15 19:50 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' "Rafael J. Wysocki" <rafael@kernel.org> - 2016-02-15 19:50 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' Marc Zyngier <marc.zyngier@arm.com> - 2016-02-15 20:00 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' "Rafael J. Wysocki" <rafael@kernel.org> - 2016-02-15 20:00 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' Marc Zyngier <marc.zyngier@arm.com> - 2016-02-15 20:10 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' "Rafael J. Wysocki" <rafael@kernel.org> - 2016-02-15 20:20 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2016-02-15 20:30 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' Guenter Roeck <linux@roeck-us.net> - 2016-02-15 20:50 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' Tony Lindgren <tony@atomide.com> - 2016-02-15 21:00 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' Tony Lindgren <tony@atomide.com> - 2016-02-15 20:50 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' Russell King - ARM Linux <linux@arm.linux.org.uk> - 2016-02-15 20:30 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' "Rafael J. Wysocki" <rafael@kernel.org> - 2016-02-15 21:50 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' Russell King - ARM Linux <linux@arm.linux.org.uk> - 2016-02-15 20:10 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' Russell King - ARM Linux <linux@arm.linux.org.uk> - 2016-02-15 20:10 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' Tony Lindgren <tony@atomide.com> - 2016-02-15 20:10 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' Guenter Roeck <linux@roeck-us.net> - 2016-02-15 20:50 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' Tony Lindgren <tony@atomide.com> - 2016-02-15 21:00 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' Guenter Roeck <linux@roeck-us.net> - 2016-02-15 21:10 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' "Rafael J. Wysocki" <rafael@kernel.org> - 2016-02-15 21:40 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' "Rafael J. Wysocki" <rafael@kernel.org> - 2016-02-15 21:40 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' Tony Lindgren <tony@atomide.com> - 2016-02-15 22:40 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' Guenter Roeck <linux@roeck-us.net> - 2016-02-16 02:40 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' Viresh Kumar <viresh.kumar@linaro.org> - 2016-02-16 02:20 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2016-02-16 02:30 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' Viresh Kumar <viresh.kumar@linaro.org> - 2016-02-16 02:40 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' Peter Maydell <peter.maydell@linaro.org> - 2016-02-15 23:40 +0100
Re: Crashes in arm qemu emulations due to 'cpufreq: governor: Replace timers with utilization ...' Guenter Roeck <linux@roeck-us.net> - 2016-02-16 00:30 +0100
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