4.16-stable review patch. If anyone has any objections, please let me know.
------------------ From: Kan Liang <[email protected]> [ Upstream commit f58385f629c87a9e210108b39c1f4950d0363ad2 ] 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]> Signed-off-by: Sasha Levin <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- tools/perf/util/mmap.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/tools/perf/util/mmap.c +++ b/tools/perf/util/mmap.c @@ -344,5 +344,11 @@ out: */ 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); }
