Messages in this thread | | | From | Arnaldo Carvalho de Melo <> | Date | Wed, 30 Oct 2019 08:50:04 -0300 | Subject | Re: [PATCH] perf script: Fix obtaining next event |
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Em Wed, Oct 30, 2019 at 03:16:10PM +0530, Ravi Bangoria escreveu: > > > On 10/30/19 2:10 PM, Chandan Rajendra wrote: > > The current code segfaults when perf.data file contains two or more > > events. This happens due to incorrect pointer arithmetic being performed > > in trace_find_next_event(). > > > > tep_handle->events is an array of pointers to 'struct tep_event'. The > > pointer arithmetic interprets tep_handle->events as an array of 'struct > > tep_event' elements. > > > > This commit replaces the usage of pointer arithmetic with calls to > > tep_get_event(). > > > > Fixes: bb3dd7e ("tools lib traceevent, perf tools: Move struct tep_handler definition in a local header file") > > Signed-off-by: Chandan Rajendra <chandanrlinux@gmail.com> > > $ sudo ./perf record -e sched:sched_switch -e syscalls:sys_enter_openat -- make > > Without patch: > $ sudo ./perf script -g python > Segmentation fault > > With patch: > $ sudo ./perf script -g python > generated Python script: perf-script.py > > Reviewed-and-tested-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
This was fixed already in perf/core, by Steven:
commit 9bdff5b6436655d42dd30253c521e86ce07b9961 Author: Steven Rostedt (VMware) <rostedt@goodmis.org> Date: Thu Oct 17 17:05:23 2019 -0400
perf tools: Remove unused trace_find_next_event()
trace_find_next_event() was buggy and pretty much a useless helper. As there are no more users, just remove it.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Tzvetomir Stoyanov <tstoyanov@vmware.com> Cc: linux-trace-devel@vger.kernel.org Link: http://lore.kernel.org/lkml/20191017210636.224045576@goodmis.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
commit a5e05abc6b8d81148b35cd8632a4a6252383d968 Author: Steven Rostedt (VMware) <rostedt@goodmis.org> Date: Thu Oct 17 17:05:22 2019 -0400
perf scripting engines: Iterate on tep event arrays directly
Instead of calling a useless (and broken) helper function to get the next event of a tep event array, just get the array directly and iterate over it.
Note, the broken part was from trace_find_next_event() which after this will no longer be used, and can be removed.
Committer notes:
This fixes a segfault when generating python scripts from perf.data files with multiple tracepoint events, i.e. the following use case is fixed by this patch:
# perf record -e sched:* sleep 1 [ perf record: Woken up 31 times to write data ] [ perf record: Captured and wrote 0.031 MB perf.data (9 samples) ] # perf script -g python Segmentation fault (core dumped) #
Reported-by: Daniel Bristot de Oliveira <bristot@redhat.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Tzvetomir Stoyanov <tstoyanov@vmware.com> Cc: linux-trace-devel@vger.kernel.org Link: http://lkml.kernel.org/r/20191017153733.630cd5eb@gandalf.local.home Link: http://lore.kernel.org/lkml/20191017210636.061448713@goodmis.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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