On Thu, Sep 09, 2021 at 11:13:21AM +0800, 王贇 wrote: > When running with ftrace function enabled, we observed panic > as below: > > traps: PANIC: double fault, error_code: 0x0 > [snip] > RIP: 0010:perf_swevent_get_recursion_context+0x0/0x70 > [snip] > Call Trace: > <NMI> > perf_trace_buf_alloc+0x26/0xd0 > perf_ftrace_function_call+0x18f/0x2e0 > kernelmode_fixup_or_oops+0x5/0x120 > __bad_area_nosemaphore+0x1b8/0x280 > do_user_addr_fault+0x410/0x920 > exc_page_fault+0x92/0x300 > asm_exc_page_fault+0x1e/0x30 > RIP: 0010:__get_user_nocheck_8+0x6/0x13 > perf_callchain_user+0x266/0x2f0 > get_perf_callchain+0x194/0x210 > perf_callchain+0xa3/0xc0 > perf_prepare_sample+0xa5/0xa60 > perf_event_output_forward+0x7b/0x1b0 > __perf_event_overflow+0x67/0x120 > perf_swevent_overflow+0xcb/0x110 > perf_swevent_event+0xb0/0xf0 > perf_tp_event+0x292/0x410 > perf_trace_run_bpf_submit+0x87/0xc0 > perf_trace_lock_acquire+0x12b/0x170 > lock_acquire+0x1bf/0x2e0 > perf_output_begin+0x70/0x4b0 > perf_log_throttle+0xe2/0x1a0 > perf_event_nmi_handler+0x30/0x50 > nmi_handle+0xba/0x2a0 > default_do_nmi+0x45/0xf0 > exc_nmi+0x155/0x170 > end_repeat_nmi+0x16/0x55 kernel/events/Makefile has: ifdef CONFIG_FUNCTION_TRACER CFLAGS_REMOVE_core.o = $(CC_FLAGS_FTRACE) endif Which, afaict, should avoid the above, no?
