Messages in this thread |  | | Date | Tue, 2 Oct 2018 13:16:21 +0200 | From | Jiri Olsa <> | Subject | Re: perf segmentation fault from NULL dereference |
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On Tue, Oct 02, 2018 at 11:41:36AM +0100, John Garry wrote:
SNIP
> > > > > > --- > > diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c > > index 1ec1d9bc2d63..fb2a0dab3978 100644 > > --- a/tools/perf/util/header.c > > +++ b/tools/perf/util/header.c > > @@ -29,6 +29,7 @@ > > #include "symbol.h" > > #include "debug.h" > > #include "cpumap.h" > > +#include "thread_map.h" > > #include "pmu.h" > > #include "vdso.h" > > #include "strbuf.h" > > @@ -3579,6 +3580,11 @@ perf_event__synthesize_event_update_cpus(struct perf_tool *tool, > > if (!evsel->own_cpus) > > return 0; > > > > + if (!evsel->id || > > for my test, evsel->id is NULL > > > + perf_evsel__alloc_id(evsel, cpu_map__nr(evsel->cpus), > > + thread_map__nr(evsel->threads))) > > and then this function is not called as we return immediately. So did you > really want this: > > if (!evsel->id && perf_evsel__alloc_id(...)) > return -ENOMEM;
ugh.. yes ;-) thanks for the fix.. I'll double check the logic and post the patch this week
jirka
> > This looks to work: > > root@localhost:~# ./perf_debug_ record -e armv8_pmuv3_0/br_mis_pred/ sleep 1 > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 0.001 MB perf.data (7 samples) ] > root@localhost:~# ./perf_debug_ report > # To display the perf.data header info, please use --header/--header-only > option > # > # > # Total Lost Samples: 0 > # > # Samples: 7 of event 'armv8_pmuv3_0/br_mis_pred/' > # Event count (approx.): 8260 > # > # Overhead Command Shared Object Symbol > # ........ ....... ................. ...................... > # > 78.28% sleep libc-2.23.so [.] 0x00000000000faef0 > 20.53% sleep [kernel.kallsyms] [k] vmacache_find > 1.09% sleep [kernel.kallsyms] [k] find_vma > 0.10% perf_de [kernel.kallsyms] [k] perf_event_exec > > > # > # (Cannot load tips.txt file, please install perf!) > # > root@localhost:~# > > > > + return -ENOMEM; > > + > > ev = cpu_map_data__alloc(evsel->own_cpus, &size, &type, &max); > > if (!ev) > > return -ENOMEM; > > > > . > > > > > Thanks, > John >
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