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Message-ID: <CAM9d7cjM262j4ixjayz+M1BqYDuiqRmrd9ifx++XBxT830ymRQ@mail.gmail.com>
Date: Tue, 6 Oct 2020 10:25:57 +0900
From: Namhyung Kim <namhyung@...nel.org>
To: "Song Bao Hua (Barry Song)" <song.bao.hua@...ilicon.com>
Cc: Andi Kleen <ak@...ux.intel.com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Linuxarm <linuxarm@...wei.com>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Jiri Olsa <jolsa@...hat.com>,
Adrian Hunter <adrian.hunter@...el.com>,
Alexey Budankov <alexey.budankov@...ux.intel.com>
Subject: Re: [PATCH] perf evlist: fix memory corruption for Kernel PMU event
Hello,
On Fri, Oct 2, 2020 at 12:02 PM Song Bao Hua (Barry Song)
<song.bao.hua@...ilicon.com> wrote:
>
>
>
> > -----Original Message-----
> > From: Andi Kleen [mailto:ak@...ux.intel.com]
> > Sent: Friday, October 2, 2020 12:07 PM
> > To: Song Bao Hua (Barry Song) <song.bao.hua@...ilicon.com>
> > Cc: linux-kernel@...r.kernel.org; Linuxarm <linuxarm@...wei.com>; Peter
> > Zijlstra <peterz@...radead.org>; Ingo Molnar <mingo@...hat.com>; Arnaldo
> > Carvalho de Melo <acme@...nel.org>; Mark Rutland
> > <mark.rutland@....com>; Alexander Shishkin
> > <alexander.shishkin@...ux.intel.com>; Jiri Olsa <jolsa@...hat.com>;
> > Namhyung Kim <namhyung@...nel.org>; Adrian Hunter
> > <adrian.hunter@...el.com>; Alexey Budankov
> > <alexey.budankov@...ux.intel.com>
> > Subject: Re: [PATCH] perf evlist: fix memory corruption for Kernel PMU event
> >
> > On Fri, Oct 02, 2020 at 12:57:29AM +1300, Barry Song wrote:
> > > Commit 7736627b865d ("perf stat: Use affinity for closing file
> > > descriptors") will use FD(evsel, cpu, thread) to read and write file
> > > descriptors xyarray. For a kernel PMU event, this leads to serious
> > > memory corruption and perf crash.
> > > I have seen evlist->core.cpus->nr is 1 while evsel has cpus->nr with
> > > the total number of CPUs. so xyarray which is allocated by
> > > evlist->core.cpus->nr will get overflow. This leads to various
> > > segmentation faults in perf tool for kernel PMU events, eg:
> > > ./perf stat -e bus_cycles sleep 1
> > > *** Error in `./perf': free(): invalid next size (fast):
> > > 0x00000000401e6370 *** Aborted (core dumped)
> >
> > Thanks.
> >
> > I believe there is already a patch queued for this.
>
> Andi, thanks! Could you share the link or the commit ID? I'd like to take a look at the fix.
> I could still reproduce this issue in the latest linus' tree and I didn't find any commit
> related to this issue in linux-next and tip/perf/core.
I think Andi was referring to this discussion which is not merged yet:
https://lore.kernel.org/lkml/20200922031346.15051-2-liwei391@huawei.com/
I suggested a patch at the end. Can you please try it?
Thanks
Namhyung
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