• Adrian Hunter's avatar
    perf intel-pt: Fix segfault tracing transactions · 1342e0b7
    Adrian Hunter authored
    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: default avatarAndi Kleen <ak@linux.intel.com>
    Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
    Cc: Jiri Olsa <jolsa@redhat.com>
    Cc: stable@vger.kernel.org # v4.4+
    Fixes: f14445ee ("perf intel-pt: Support generating branch stack")
    Link: http://lkml.kernel.org/r/1460977068-11566-1-git-send-email-adrian.hunter@intel.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    1342e0b7
intel-pt.c 53 KB