On Mon, 4 May 2020 09:27:08 +0300 "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@xxxxxxxxx> wrote: > The trace-cmd report command crashes while displaying a file recorded with "--proc-map" and "-B" options: > #trace-cmd record --proc-map -B test -e sched -F sleep 1 > The "--proc-map" options saves the address map of "sleep" into the trace.dat file. This > information is used by KernelShark. The "-B" options traces the specified events into a > ftrace instance "test". > When such file is opened using libtracecmd APIs, the proc-map is parsed and saved into > a tracecmd_input handler, as linked list "pid_maps". Later, when the ftrace instance > "test" is parsed, a copy of this handler is used to fill it with the instance's trace data. > Both tracecmd_input handlers share the same "pid_maps" list, thus leads to a double > free of the list, when handlers are destroyed. > As this "pid_maps" is not used in ftrace buffers, the "pid_maps" list of the copy can be > initialized to NULL. > > Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx> FYI, I changed the subject and body to this: trace-cmd: Fix trace-cmd report crash while displaying trace.dat with --proc-map and -B options The trace-cmd report command crashes while displaying a file recorded with "--proc-map" and "-B" options: # trace-cmd record --proc-map -B test -e sched -F sleep 1 The "--proc-map" options saves the address map of "sleep" into the trace.dat file. This information is used by KernelShark. The "-B" option traces the specified events into a ftrace instance "test". When such a file is opened using libtracecmd APIs, the proc-map is parsed and saved into a tracecmd_input handler, as linked list "pid_maps". Later, when the ftrace instance "test" is parsed, a copy of this handler is used to fill it with the instance's trace data. Both tracecmd_input handlers share the same "pid_maps" list, thus leads to a double free of the list when the handlers are destroyed. As this "pid_maps" is not used in ftrace buffers, the "pid_maps" list of the copy can be initialized to NULL. -- Steve
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