From 1342e0b7a6c1a060c593037fbac9f4b717f1cb3b Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Mon, 18 Apr 2016 13:57:48 +0300 Subject: [PATCH] perf intel-pt: Fix segfault tracing transactions Tracing a workload that uses transactions gave a seg fault as follows: perf record -e intel_pt// workload perf report Program received signal SIGSEGV, Segmentation fault. 0x000000000054b58c in intel_pt_reset_last_branch_rb (ptq=0x1a36110) at util/intel-pt.c:929 929 ptq->last_branch_rb->nr = 0; (gdb) p ptq->last_branch_rb $1 = (struct branch_stack *) 0x0 (gdb) up 1148 intel_pt_reset_last_branch_rb(ptq); (gdb) l 1143 if (ret) 1144 pr_err("Intel Processor Trace: failed to deliver transaction event 1145 ret); 1146 1147 if (pt->synth_opts.callchain) 1148 intel_pt_reset_last_branch_rb(ptq); 1149 1150 return ret; 1151 } 1152 (gdb) p pt->synth_opts.callchain $2 = true (gdb) (gdb) bt #0 0x000000000054b58c in intel_pt_reset_last_branch_rb (ptq=0x1a36110) #1 0x000000000054c1e0 in intel_pt_synth_transaction_sample (ptq=0x1a36110) #2 0x000000000054c5b2 in intel_pt_sample (ptq=0x1a36110) Caused by checking the 'callchain' flag when it should have been the 'last_branch' flag. Fix that. Reported-by: Andi Kleen Signed-off-by: Adrian Hunter Cc: Jiri Olsa Cc: stable@vger.kernel.org # v4.4+ Fixes: f14445ee72c5 ("perf intel-pt: Support generating branch stack") Link: http://lkml.kernel.org/r/1460977068-11566-1-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/intel-pt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c index 407f11b97c8d..617578440989 100644 --- a/tools/perf/util/intel-pt.c +++ b/tools/perf/util/intel-pt.c @@ -1130,7 +1130,7 @@ static int intel_pt_synth_transaction_sample(struct intel_pt_queue *ptq) pr_err("Intel Processor Trace: failed to deliver transaction event, error %d\n", ret); - if (pt->synth_opts.callchain) + if (pt->synth_opts.last_branch) intel_pt_reset_last_branch_rb(ptq); return ret; -- 2.20.1