From: Jiri Olsa <jolsa@redhat.com>
To: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Andi Kleen <ak@linux.intel.com>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3] perf session: fix decompression of PERF_RECORD_COMPRESSED records
Date: Tue, 19 Nov 2019 21:05:10 +0100 [thread overview]
Message-ID: <20191119200510.GA7364@krava> (raw)
In-Reply-To: <cf782c34-f3f8-2f9f-d6ab-145cee0d5322@linux.intel.com>
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
next prev parent reply other threads:[~2019-11-19 20:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-18 14:21 [PATCH v3] perf session: fix decompression of PERF_RECORD_COMPRESSED records Alexey Budankov
2019-11-19 20:05 ` Jiri Olsa [this message]
2019-11-19 22:33 ` Arnaldo Carvalho de Melo
2019-11-23 8:15 ` [tip: perf/core] perf session: Fix " tip-bot2 for Alexey Budankov
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