Messages in this thread | | | From | Michael Ellerman <> | Subject | Re: [PATCH] powerpc/sysrq: Fix oops whem ppmu is not registered | Date | Tue, 19 Sep 2017 20:00:49 +1000 |
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Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com> writes:
> Kernel crashes if power pmu is not registered and user tries to dump > regs with 'echo p > /proc/sysrq-trigger'. Sample log: > > Unable to handle kernel paging request for data at address 0x00000008 > Faulting instruction address: 0xc0000000000d52f0 > > NIP [c0000000000d52f0] perf_event_print_debug+0x10/0x230 > LR [c00000000058a938] sysrq_handle_showregs+0x38/0x50 > Call Trace: > printk+0x38/0x4c (unreliable) > __handle_sysrq+0xe4/0x270 > write_sysrq_trigger+0x64/0x80 > proc_reg_write+0x80/0xd0 > __vfs_write+0x40/0x200 > vfs_write+0xc8/0x240 > SyS_write+0x60/0x110 > system_call+0x58/0x6c
Thanks.
I added:
Fixes: 5f6d0380c640 ("powerpc/perf: Define perf_event_print_debug() to print PMU register values")
But I don't think I'll Cc stable, I can't think why we'd ever *not* have a ppmu registered. How did you hit it?
cheers
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