Messages in this thread Patch in this message | | | From | Josef Bacik <> | Subject | [PATCH] trace-cmd: make sure we have a pending pid in trace-hist | Date | Fri, 8 Aug 2014 16:26:17 -0400 |
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I have a trace.dat file where we lost some events and so we didn't have the corresponding event to go with the stack trace. This made trace-cmd hist segfault because it unconditionally pushes the pending_pid's function onto the stack trace. In this case pending_pid < 0, which means we didn't have a pending stack trace, so we got garbage in the call chain and hilarity ensued. Fix this by only pushing the pending call chain if there actually is one, and also don't reset the current call chain if there isn't actually one there either. This fixed my segfault. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com> --- trace-hist.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/trace-hist.c b/trace-hist.c index 73820de..574549e 100644 --- a/trace-hist.c +++ b/trace-hist.c @@ -453,9 +453,11 @@ process_kernel_stack(struct pevent *pevent, struct pevent_record *record) } } else { /* function stack trace? */ - copy_stack_to_pending(current_pid); - free(ips); - reset_stack(); + if (current_pid >= 0) { + copy_stack_to_pending(current_pid); + free(ips); + reset_stack(); + } } current_pid = pid; @@ -482,8 +484,10 @@ process_kernel_stack(struct pevent *pevent, struct pevent_record *record) push_stack_func(func); } - push_stack_func(pending_ips[pending_ips_idx - 1]); - reset_pending_stack(); + if (pending_pid >= 0) { + push_stack_func(pending_ips[pending_ips_idx - 1]); + reset_pending_stack(); + } save_call_chain(current_pid, ips, ips_idx, 1); if (do_restore) restore_stack(current_pid); -- 2.0.0
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