From: kan.liang@linux.intel.com
To: acme@kernel.org, mingo@redhat.com, linux-kernel@vger.kernel.org
Cc: jolsa@kernel.org, namhyung@kernel.org, wangnan0@huawei.com,
Kan Liang <kan.liang@linux.intel.com>
Subject: [PATCH] perf mmap: Fix accessing unmapped mmap in perf_mmap__read_done()
Date: Mon, 26 Mar 2018 09:42:09 -0400 [thread overview]
Message-ID: <1522071729-16776-1-git-send-email-kan.liang@linux.intel.com> (raw)
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
next reply other threads:[~2018-03-26 13:43 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-26 13:42 kan.liang [this message]
2018-03-26 14:26 ` [PATCH] perf mmap: Fix accessing unmapped mmap in perf_mmap__read_done() Arnaldo Carvalho de Melo
2018-03-26 14:41 ` Arnaldo Carvalho de Melo
2018-03-26 14:51 ` Liang, Kan
2018-03-29 13:58 ` [tip:perf/core] perf mmap: Be consistent when checking for an unmaped ring buffer tip-bot for Arnaldo Carvalho de Melo
2018-03-29 13:58 ` [tip:perf/core] perf mmap: Fix accessing unmapped mmap in perf_mmap__read_done() tip-bot for Kan Liang
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