Messages in this thread Patch in this message | | | From | kan.liang@linux ... | Subject | [PATCH] perf mmap: Fix accessing unmapped mmap in perf_mmap__read_done() | Date | Mon, 26 Mar 2018 09:42:09 -0400 |
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From: Kan Liang <kan.liang@linux.intel.com>
There is 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().
Fixes: ee023de05f35 ("perf mmap: Introduce perf_mmap__read_done()") Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Kan Liang <kan.liang@linux.intel.com> --- 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 38ca3ff..f6cfc52 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); } -- 2.4.11
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