Re: perf segfault in in ordered_events__free()
On Wed, Jan 16, 2019 at 11:33:55PM -0800, Song Liu wrote: > On Wed, Jan 16, 2019 at 1:53 PM Song Liu wrote: > > > > Thanks Jiri! > > > > On Wed, Jan 16, 2019 at 1:34 PM Jiri Olsa wrote: > > > > > > On Wed, Jan 16, 2019 at 10:57:49AM -0800, Song Liu wrote: > > > > Hi, > > > > > > > > We are debugging a segfault of perf in ordered_events__free(). > > > > > > hi, > > > any backtrace or info on how to reproduce it? > > > > Here is the backtrace: > > > > #0 0x00500055 in ordered_events(float, long double,...)(...) () > > #1 0x00500196 in ordered_events.reinit () > > #2 0x004fe413 in perf_session.process_events () > > #3 0x00440431 in cmd_record () > > #4 0x004a439f in run_builtin () > > #5 0x0042b3e5 in main ()" > > > > > > > > > Disassemble shows the segfault was caused by oe->buff == NULL > > > > in the following line: > > > > > > > > /* > > > > * Current buffer might not have all the events allocated > > > > * yet, we need to free only allocated ones ... > > > > */ > > > > list_del(>buffer->list); > > > > > > > > After poking around the code, I suspect it is caused by the following > > > > condition in alloc_event(): > > > > > > > > } else if (oe->buffer) { > > > > new = >buffer->event[oe->buffer_idx]; > > > > if (++oe->buffer_idx == MAX_SAMPLE_BUFFER) > > > > oe->buffer = NULL; > > > > > > > > > argh.. yea, we need to check oe->buffer in ordered_events__free > > > > > > would attached change fix it for you? > > > > Let me try roll a fixed version to confirm. > > Yes, the patch fixes this segfault. Please CC me on the official patch to > back port the official version. thanks for testing, will post it today jirka
Re: perf segfault in in ordered_events__free()
On Wed, Jan 16, 2019 at 1:53 PM Song Liu wrote: > > Thanks Jiri! > > On Wed, Jan 16, 2019 at 1:34 PM Jiri Olsa wrote: > > > > On Wed, Jan 16, 2019 at 10:57:49AM -0800, Song Liu wrote: > > > Hi, > > > > > > We are debugging a segfault of perf in ordered_events__free(). > > > > hi, > > any backtrace or info on how to reproduce it? > > Here is the backtrace: > > #0 0x00500055 in ordered_events(float, long double,...)(...) () > #1 0x00500196 in ordered_events.reinit () > #2 0x004fe413 in perf_session.process_events () > #3 0x00440431 in cmd_record () > #4 0x004a439f in run_builtin () > #5 0x0042b3e5 in main ()" > > > > > > Disassemble shows the segfault was caused by oe->buff == NULL > > > in the following line: > > > > > > /* > > > * Current buffer might not have all the events allocated > > > * yet, we need to free only allocated ones ... > > > */ > > > list_del(>buffer->list); > > > > > > After poking around the code, I suspect it is caused by the following > > > condition in alloc_event(): > > > > > > } else if (oe->buffer) { > > > new = >buffer->event[oe->buffer_idx]; > > > if (++oe->buffer_idx == MAX_SAMPLE_BUFFER) > > > oe->buffer = NULL; > > > > > > argh.. yea, we need to check oe->buffer in ordered_events__free > > > > would attached change fix it for you? > > Let me try roll a fixed version to confirm. Yes, the patch fixes this segfault. Please CC me on the official patch to back port the official version. Thanks, Song
Re: perf segfault in in ordered_events__free()
Thanks Jiri! On Wed, Jan 16, 2019 at 1:34 PM Jiri Olsa wrote: > > On Wed, Jan 16, 2019 at 10:57:49AM -0800, Song Liu wrote: > > Hi, > > > > We are debugging a segfault of perf in ordered_events__free(). > > hi, > any backtrace or info on how to reproduce it? Here is the backtrace: #0 0x00500055 in ordered_events(float, long double,...)(...) () #1 0x00500196 in ordered_events.reinit () #2 0x004fe413 in perf_session.process_events () #3 0x00440431 in cmd_record () #4 0x004a439f in run_builtin () #5 0x0042b3e5 in main ()" > > > Disassemble shows the segfault was caused by oe->buff == NULL > > in the following line: > > > > /* > > * Current buffer might not have all the events allocated > > * yet, we need to free only allocated ones ... > > */ > > list_del(>buffer->list); > > > > After poking around the code, I suspect it is caused by the following > > condition in alloc_event(): > > > > } else if (oe->buffer) { > > new = >buffer->event[oe->buffer_idx]; > > if (++oe->buffer_idx == MAX_SAMPLE_BUFFER) > > oe->buffer = NULL; > > > argh.. yea, we need to check oe->buffer in ordered_events__free > > would attached change fix it for you? Let me try roll a fixed version to confirm. Thanks again! Song > > thanks, > jirka > > > --- > diff --git a/tools/perf/util/ordered-events.c > b/tools/perf/util/ordered-events.c > index 897589507d97..ea523d3b248f 100644 > --- a/tools/perf/util/ordered-events.c > +++ b/tools/perf/util/ordered-events.c > @@ -391,8 +391,10 @@ void ordered_events__free(struct ordered_events *oe) > * Current buffer might not have all the events allocated > * yet, we need to free only allocated ones ... > */ > - list_del(>buffer->list); > - ordered_events_buffer__free(oe->buffer, oe->buffer_idx, oe); > + if (oe->buffer) { > + list_del(>buffer->list); > + ordered_events_buffer__free(oe->buffer, oe->buffer_idx, oe); > + } > > /* ... and continue with the rest */ > list_for_each_entry_safe(buffer, tmp, >to_free, list) {
Re: perf segfault in in ordered_events__free()
On Wed, Jan 16, 2019 at 10:57:49AM -0800, Song Liu wrote: > Hi, > > We are debugging a segfault of perf in ordered_events__free(). hi, any backtrace or info on how to reproduce it? > Disassemble shows the segfault was caused by oe->buff == NULL > in the following line: > > /* > * Current buffer might not have all the events allocated > * yet, we need to free only allocated ones ... > */ > list_del(>buffer->list); > > After poking around the code, I suspect it is caused by the following > condition in alloc_event(): > > } else if (oe->buffer) { > new = >buffer->event[oe->buffer_idx]; > if (++oe->buffer_idx == MAX_SAMPLE_BUFFER) > oe->buffer = NULL; argh.. yea, we need to check oe->buffer in ordered_events__free would attached change fix it for you? thanks, jirka --- diff --git a/tools/perf/util/ordered-events.c b/tools/perf/util/ordered-events.c index 897589507d97..ea523d3b248f 100644 --- a/tools/perf/util/ordered-events.c +++ b/tools/perf/util/ordered-events.c @@ -391,8 +391,10 @@ void ordered_events__free(struct ordered_events *oe) * Current buffer might not have all the events allocated * yet, we need to free only allocated ones ... */ - list_del(>buffer->list); - ordered_events_buffer__free(oe->buffer, oe->buffer_idx, oe); + if (oe->buffer) { + list_del(>buffer->list); + ordered_events_buffer__free(oe->buffer, oe->buffer_idx, oe); + } /* ... and continue with the rest */ list_for_each_entry_safe(buffer, tmp, >to_free, list) {
perf segfault in in ordered_events__free()
Hi, We are debugging a segfault of perf in ordered_events__free(). Disassemble shows the segfault was caused by oe->buff == NULL in the following line: /* * Current buffer might not have all the events allocated * yet, we need to free only allocated ones ... */ list_del(>buffer->list); After poking around the code, I suspect it is caused by the following condition in alloc_event(): } else if (oe->buffer) { new = >buffer->event[oe->buffer_idx]; if (++oe->buffer_idx == MAX_SAMPLE_BUFFER) oe->buffer = NULL; Does this theory make sense? If so, what would be the best fix? Thanks in advance! Song