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| author |   Arnaldo Carvalho de Melo <acme@redhat.com> | 2018-03-26 11:42:15 -0300 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2018-03-27 13:13:38 -0300 |
| commit | 895e3b06fc2ce438adc62cb13d31ea001dcfda16 (patch) | |
| tree | 15651e1f12cc6aff270f86f2da3a23c8ae4bc673 /tools/perf | |
| parent | perf mmap: Fix accessing unmapped mmap in perf_mmap__read_done() (diff) | |
| download | wireguard-linux-895e3b06fc2ce438adc62cb13d31ea001dcfda16.tar.xz wireguard-linux-895e3b06fc2ce438adc62cb13d31ea001dcfda16.zip | |
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.c | 13 |
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)) { |