Commit 7a310c64 authored by Li RongQing's avatar Li RongQing Committed by Ingo Molnar
Browse files

perf/x86/intel/bts: Check if bts_ctx is allocated when calling BTS functions 



bts_ctx might not be allocated, for example if the CPU has X86_FEATURE_PTI,
but intel_bts_disable/enable_local() and intel_bts_interrupt() are called
unconditionally from intel_pmu_handle_irq() and crash on bts_ctx.

So check if bts_ctx is allocated when calling BTS functions.

Fixes: 3acfcefa ("perf/x86/intel/bts: Allocate bts_ctx only if necessary")
Reported-by: default avatarJiri Olsa <olsajiri@gmail.com>
Tested-by: default avatarJiri Olsa <jolsa@kernel.org>
Suggested-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Suggested-by: default avatarDave Hansen <dave.hansen@intel.com>
Signed-off-by: default avatarLi RongQing <lirongqing@baidu.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250306051102.2642-1-lirongqing@baidu.com
parent fa6192ad

arch/x86/events/intel/bts.c

+20 −5
Original line number Diff line number Diff line
@@ -338,9 +338,14 @@ static void bts_event_stop(struct perf_event *event, int flags) 


void intel_bts_enable_local(void)

{

	struct bts_ctx *bts = this_cpu_ptr(bts_ctx);

	int state = READ_ONCE(bts->state);

	struct bts_ctx *bts;

	int state;



	if (!bts_ctx)

		return;



	bts = this_cpu_ptr(bts_ctx);

	state = READ_ONCE(bts->state);

	/*

	 * Here we transition from INACTIVE to ACTIVE;

	 * if we instead are STOPPED from the interrupt handler,
@@ -358,7 +363,12 @@ void intel_bts_enable_local(void) 


void intel_bts_disable_local(void)

{

	struct bts_ctx *bts = this_cpu_ptr(bts_ctx);

	struct bts_ctx *bts;



	if (!bts_ctx)

		return;



	bts = this_cpu_ptr(bts_ctx);



	/*

	 * Here we transition from ACTIVE to INACTIVE;
@@ -450,12 +460,17 @@ bts_buffer_reset(struct bts_buffer *buf, struct perf_output_handle *handle) 
int intel_bts_interrupt(void)

{

	struct debug_store *ds = this_cpu_ptr(&cpu_hw_events)->ds;

	struct bts_ctx *bts = this_cpu_ptr(bts_ctx);

	struct perf_event *event = bts->handle.event;

	struct bts_ctx *bts;

	struct perf_event *event;

	struct bts_buffer *buf;

	s64 old_head;

	int err = -ENOSPC, handled = 0;



	if (!bts_ctx)

		return 0;



	bts = this_cpu_ptr(bts_ctx);

	event = bts->handle.event;

	/*

	 * The only surefire way of knowing if this NMI is ours is by checking

	 * the write ptr against the PMI threshold.