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authorArnaldo Carvalho de Melo <acme@redhat.com>2018-03-26 17:42:15 +0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2018-03-27 19:13:38 +0300
commit895e3b06fc2ce438adc62cb13d31ea001dcfda16 (patch)
tree15651e1f12cc6aff270f86f2da3a23c8ae4bc673 /tools/perf
parentf58385f629c87a9e210108b39c1f4950d0363ad2 (diff)
downloadlinux-895e3b06fc2ce438adc62cb13d31ea001dcfda16.tar.xz
perf mmap: Be consistent when checking for an unmaped ring buffer
The previous patch is insufficient to cure the reported 'perf trace' segfault, as it only cures the perf_mmap__read_done() case, moving the segfault to perf_mmap__read_init() functio, fix it by doing the same refcount check. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kan Liang <kan.liang@intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Fixes: 8872481bd048 ("perf mmap: Introduce perf_mmap__read_init()") Link: https://lkml.kernel.org/r/20180326144127.GF18897@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf')
-rw-r--r--tools/perf/util/mmap.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
index f6cfc52ff1fe..fc832676a798 100644
--- a/tools/perf/util/mmap.c
+++ b/tools/perf/util/mmap.c
@@ -234,7 +234,7 @@ static int overwrite_rb_find_range(void *buf, int mask, u64 *start, u64 *end)
/*
* Report the start and end of the available data in ringbuffer
*/
-int perf_mmap__read_init(struct perf_mmap *md)
+static int __perf_mmap__read_init(struct perf_mmap *md)
{
u64 head = perf_mmap__read_head(md);
u64 old = md->prev;
@@ -268,6 +268,17 @@ int perf_mmap__read_init(struct perf_mmap *md)
return 0;
}
+int perf_mmap__read_init(struct perf_mmap *map)
+{
+ /*
+ * Check if event was unmapped due to a POLLHUP/POLLERR.
+ */
+ if (!refcount_read(&map->refcnt))
+ return -ENOENT;
+
+ return __perf_mmap__read_init(map);
+}
+
int perf_mmap__push(struct perf_mmap *md, void *to,
int push(void *to, void *buf, size_t size))
{