linux-kernel - Re: [PATCH] perf: cs-etm: Fix the assert() to handle captured and unprocessed cpu trace

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <ZvxIUSz1O92BGOiP@x1>
Date: Tue, 1 Oct 2024 16:06:57 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Namhyung Kim <namhyung@...nel.org>
Cc: James Clark <james.clark@...aro.org>,
	Ilkka Koskinen <ilkka@...amperecomputing.com>,
	linux-arm-kernel@...ts.infradead.org, coresight@...ts.linaro.org,
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
	John Garry <john.g.garry@...cle.com>, Will Deacon <will@...nel.org>,
	Mike Leach <mike.leach@...aro.org>, Leo Yan <leo.yan@...ux.dev>,
	Suzuki K Poulose <suzuki.poulose@....com>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>, Mark Rutland <mark.rutland@....com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Jiri Olsa <jolsa@...nel.org>, Ian Rogers <irogers@...gle.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	"Liang, Kan" <kan.liang@...ux.intel.com>
Subject: Re: [PATCH] perf: cs-etm: Fix the assert() to handle captured and
 unprocessed cpu trace

On Wed, Sep 25, 2024 at 04:04:55PM -0700, Namhyung Kim wrote:
> On Wed, Sep 25, 2024 at 10:54:31AM +0100, James Clark wrote:
> > 
> > 
> > On 25/09/2024 12:39 am, Ilkka Koskinen wrote:
> > > If one builds perf with DEBUG=1, captures data on multiple CPUs and
> > > finally runs 'perf report -C <cpu>' for only one of the cpus, assert()
> > > aborts the program. This happens because there are empty queues with
> > > format set. This patch changes the condition to abort only if a queue
> > > is not empty and if the format is unset.
> > > 
> > >    $ make -C tools/perf DEBUG=1 CORESIGHT=1 CSLIBS=/usr/lib CSINCLUDES=/usr/include install
> > >    $ perf record -o kcore --kcore -e cs_etm/timestamp/k -s -C 0-1 dd if=/dev/zero of=/dev/null bs=1M count=1
> > >    $ perf report --input kcore/data --vmlinux=/home/ikoskine/projects/linux/vmlinux -C 1
> > >    Aborted (core dumped)
> > > 
> > > Fixes: 57880a7966be ("perf: cs-etm: Allocate queues for all CPUs")
> > > Signed-off-by: Ilkka Koskinen <ilkka@...amperecomputing.com>
> > > ---
> > >   tools/perf/util/cs-etm.c | 2 +-
> > >   1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
> > > index 90f32f327b9b..40f047baef81 100644
> > > --- a/tools/perf/util/cs-etm.c
> > > +++ b/tools/perf/util/cs-etm.c
> > > @@ -3323,7 +3323,7 @@ static int cs_etm__create_decoders(struct cs_etm_auxtrace *etm)
> > >   		 * Don't create decoders for empty queues, mainly because
> > >   		 * etmq->format is unknown for empty queues.
> > >   		 */
> > > -		assert(empty == (etmq->format == UNSET));
> > > +		assert(empty || etmq->format != UNSET);
> > >   		if (empty)
> > >   			continue;
> > 
> > Oops I didn't realize you could filter on CPU in report mode. Thanks for the
> > fix. Adding a test to the end of test_arm_coresight.sh might be quite
> > useful. Either way:
> > 
> > Reviewed-by: James Clark <james.clark@...aro.org>
>  
> Thanks, it should go to the perf-tool.  Arnaldo, please pick up.

Right, picking it now.

Thanks,

- Arnaldo