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author | Alexey Budankov <alexey.budankov@linux.intel.com> | 2019-11-18 17:21:03 +0300 |
---|---|---|
committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2019-11-19 19:31:55 -0300 |
commit | bb1835a3b86c73aa534ef6430ad40223728dfbc0 (patch) | |
tree | e44b64c5c4d9d316522876b773f2c8ffde5ee7ef /tools/perf | |
parent | 0e3149f86b99ddabde8c5029eea0a9267e34f1a0 (diff) | |
download | linux-bb1835a3b86c73aa534ef6430ad40223728dfbc0.tar.bz2 |
perf session: Fix decompression of PERF_RECORD_COMPRESSED records
Avoid termination of trace loading in case the last record in the
decompressed buffer partly resides in the following mmaped
PERF_RECORD_COMPRESSED record.
In this case NULL value returned by fetch_mmaped_event() means to
proceed to the next mmaped record then decompress it and load compressed
events.
The issue can be reproduced like this:
$ perf record -z -- some_long_running_workload
$ perf report --stdio -vv
decomp (B): 44519 to 163000
decomp (B): 48119 to 174800
decomp (B): 65527 to 131072
fetch_mmaped_event: head=0x1ffe0 event->header_size=0x28, mmap_size=0x20000: fuzzed perf.data?
Error:
failed to process sample
...
Testing:
71: Zstd perf.data compression/decompression : Ok
$ tools/perf/perf report -vv --stdio
decomp (B): 59593 to 262160
decomp (B): 4438 to 16512
decomp (B): 285 to 880
Looking at the vmlinux_path (8 entries long)
Using vmlinux for symbols
decomp (B): 57474 to 261248
prefetch_event: head=0x3fc78 event->header_size=0x28, mmap_size=0x3fc80: fuzzed or compressed perf.data?
decomp (B): 25 to 32
decomp (B): 52 to 120
...
Fixes: 57fc032ad643 ("perf session: Avoid infinite loop when seeing invalid header.size")
Link: https://marc.info/?l=linux-kernel&m=156580812427554&w=2
Co-developed-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/cf782c34-f3f8-2f9f-d6ab-145cee0d5322@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf')
-rw-r--r-- | tools/perf/util/session.c | 44 |
1 files changed, 27 insertions, 17 deletions
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c index f07b8ecb91bc..8454a650146b 100644 --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -1958,8 +1958,8 @@ out_err: } static union perf_event * -fetch_mmaped_event(struct perf_session *session, - u64 head, size_t mmap_size, char *buf) +prefetch_event(char *buf, u64 head, size_t mmap_size, + bool needs_swap, union perf_event *error) { union perf_event *event; @@ -1971,20 +1971,32 @@ fetch_mmaped_event(struct perf_session *session, return NULL; event = (union perf_event *)(buf + head); + if (needs_swap) + perf_event_header__bswap(&event->header); - if (session->header.needs_swap) + if (head + event->header.size <= mmap_size) + return event; + + /* We're not fetching the event so swap back again */ + if (needs_swap) perf_event_header__bswap(&event->header); - if (head + event->header.size > mmap_size) { - /* We're not fetching the event so swap back again */ - if (session->header.needs_swap) - perf_event_header__bswap(&event->header); - pr_debug("%s: head=%#" PRIx64 " event->header_size=%#x, mmap_size=%#zx: fuzzed perf.data?\n", - __func__, head, event->header.size, mmap_size); - return ERR_PTR(-EINVAL); - } + pr_debug("%s: head=%#" PRIx64 " event->header_size=%#x, mmap_size=%#zx:" + " fuzzed or compressed perf.data?\n",__func__, head, event->header.size, mmap_size); - return event; + return error; +} + +static union perf_event * +fetch_mmaped_event(u64 head, size_t mmap_size, char *buf, bool needs_swap) +{ + return prefetch_event(buf, head, mmap_size, needs_swap, ERR_PTR(-EINVAL)); +} + +static union perf_event * +fetch_decomp_event(u64 head, size_t mmap_size, char *buf, bool needs_swap) +{ + return prefetch_event(buf, head, mmap_size, needs_swap, NULL); } static int __perf_session__process_decomp_events(struct perf_session *session) @@ -1997,10 +2009,8 @@ static int __perf_session__process_decomp_events(struct perf_session *session) return 0; while (decomp->head < decomp->size && !session_done()) { - union perf_event *event = fetch_mmaped_event(session, decomp->head, decomp->size, decomp->data); - - if (IS_ERR(event)) - return PTR_ERR(event); + union perf_event *event = fetch_decomp_event(decomp->head, decomp->size, decomp->data, + session->header.needs_swap); if (!event) break; @@ -2100,7 +2110,7 @@ remap: } more: - event = fetch_mmaped_event(session, head, mmap_size, buf); + event = fetch_mmaped_event(head, mmap_size, buf, session->header.needs_swap); if (IS_ERR(event)) return PTR_ERR(event); |