On 02/15/2016 11:01 AM, Tony Lindgren wrote:
* Rafael J. Wysocki <rafael@xxxxxxxxxx> [160215 10:44]:On Mon, Feb 15, 2016 at 6:05 PM, Guenter Roeck <linux@xxxxxxxxxxxx> 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+0x34/0x38Since 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.That's not even an SMP machine? I suspect a bunch of out of the 65 boot failures here are related to this: https://kernelci.org/boot/all/job/next/kernel/next-20160215/ The SMP ones seem to fail with some regulator issues?
There is another problem, introduced with 6a0712f6f199e ("PM / OPP: Add
dev_pm_opp_set_rate()"). The kernelci boot log for next-20160212:omap3-overo-tobi
and others experience that problem.
Essentially, the code now assumes that a CPU clock always has a voltage
regulator attached to it, which is not correct. I sent out a patch to fix
that problem a minute ago.
Guenter
--
To unsubscribe from this list: send the line "unsubscribe linux-next" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
