Re: [PATCH] powerpc/perf: Fix crash with 'perf_instruction_pointer' when pmu is not set
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From: Michael Ellerman <hidden>
Date: 2021-06-26 10:46:10
On Thu, 17 Jun 2021 13:55:06 -0400, Athira Rajeev wrote:
On systems without any specific PMU driver support registered, running perf record causes Oops. The relevant portion from call trace: BUG: Kernel NULL pointer dereference on read at 0x00000040 Faulting instruction address: 0xc0021f0c Oops: Kernel access of bad area, sig: 11 [#1] BE PAGE_SIZE=4K PREEMPT CMPCPRO SAF3000 DIE NOTIFICATION CPU: 0 PID: 442 Comm: null_syscall Not tainted 5.13.0-rc6-s3k-dev-01645-g7649ee3d2957 #5164 NIP: c0021f0c LR: c00e8ad8 CTR: c00d8a5c NIP [c0021f0c] perf_instruction_pointer+0x10/0x60 LR [c00e8ad8] perf_prepare_sample+0x344/0x674 Call Trace: [e6775880] [c00e8810] perf_prepare_sample+0x7c/0x674 (unreliable) [e67758c0] [c00e8e44] perf_event_output_forward+0x3c/0x94 [e6775910] [c00dea8c] __perf_event_overflow+0x74/0x14c [e6775930] [c00dec5c] perf_swevent_hrtimer+0xf8/0x170 [e6775a40] [c008c8d0] __hrtimer_run_queues.constprop.0+0x160/0x318 [e6775a90] [c008d94c] hrtimer_interrupt+0x148/0x3b0 [e6775ae0] [c000c0c0] timer_interrupt+0xc4/0x22c [e6775b10] [c00046f0] Decrementer_virt+0xb8/0xbc [...]
Applied to powerpc/fixes.
[1/1] powerpc/perf: Fix crash with 'perf_instruction_pointer' when pmu is not set
https://git.kernel.org/powerpc/c/60b7ed54a41b550d50caf7f2418db4a7e75b5bdc
cheers