From: Kan Liang <[email protected]> There is a segmentation fault when running 'perf trace'. For example:
[root@jouet e]# perf trace -e *chdir -o /tmp/bla perf report --ignore-vmlinux -i ../perf.data The perf_mmap__consume() could unmap the mmap. It needs to check the refcnt in perf_mmap__read_done(). Reported-by: Arnaldo Carvalho de Melo <[email protected]> Signed-off-by: Kan Liang <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Wang Nan <[email protected]> Fixes: ee023de05f35 ("perf mmap: Introduce perf_mmap__read_done()") Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]> --- tools/perf/util/mmap.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c index 38ca3ffb9d61..f6cfc52ff1fe 100644 --- a/tools/perf/util/mmap.c +++ b/tools/perf/util/mmap.c @@ -317,5 +317,11 @@ int perf_mmap__push(struct perf_mmap *md, void *to, */ void perf_mmap__read_done(struct perf_mmap *map) { + /* + * Check if event was unmapped due to a POLLHUP/POLLERR. + */ + if (!refcount_read(&map->refcnt)) + return; + map->prev = perf_mmap__read_head(map); } -- 2.14.3
