Messages in this thread | | | Date | Tue, 19 Nov 2019 21:05:10 +0100 | From | Jiri Olsa <> | Subject | Re: [PATCH v3] perf session: fix decompression of PERF_RECORD_COMPRESSED records |
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On Mon, Nov 18, 2019 at 05:21:03PM +0300, Alexey Budankov wrote: > > 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> > Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
thanks, jirka
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