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Date: Wed, 20 Mar 2024 11:49:55 -0300
From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Ian Rogers <irogers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@redhat.com>,
	Namhyung Kim <namhyung@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@kernel.org>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Christian Brauner <brauner@kernel.org>,
	James Clark <james.clark@arm.com>,
	Kan Liang <kan.liang@linux.intel.com>,
	Tim Chen <tim.c.chen@linux.intel.com>,
	Athira Rajeev <atrajeev@linux.vnet.ibm.com>,
	Yicong Yang <yangyicong@hisilicon.com>,
	Kajol Jain <kjain@linux.ibm.com>,
	Disha Goel <disgoel@linux.ibm.com>,
	K Prateek Nayak <kprateek.nayak@amd.com>,
	Song Liu <songliubraving@fb.com>, linux-perf-users@vger.kernel.org,
	linux-kernel@vger.kernel.org, bpf@vger.kernel.org
Subject: Re: [PATCH v1 1/4] perf record: Delete session after stopping
 sideband thread
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On Tue, Mar 19, 2024 at 09:42:26PM -0700, Ian Rogers wrote:
> On Thu, Feb 29, 2024 at 11:50 PM Ian Rogers <irogers@google.com> wrote:
> >
> > On Thu, Feb 29, 2024 at 11:47 PM Ian Rogers <irogers@google.com> wrote:
> > >
> > > The session has a header in it which contains a perf env with
> > > bpf_progs. The bpf_progs are accessed by the sideband thread and so
> > > the sideband thread must be stopped before the session is deleted, to
> > > avoid a use after free.  This error was detected by AddressSanitizer
> > > in the following:
> > >
> > > ```
> > > ==2054673==ERROR: AddressSanitizer: heap-use-after-free on address 0x61d000161e00 at pc 0x55769289de54 bp 0x7f9df36d4ab0 sp 0x7f9df36d4aa8
> > > READ of size 8 at 0x61d000161e00 thread T1
> > >     #0 0x55769289de53 in __perf_env__insert_bpf_prog_info util/env.c:42
> > >     #1 0x55769289dbb1 in perf_env__insert_bpf_prog_info util/env.c:29
> > >     #2 0x557692bbae29 in perf_env__add_bpf_info util/bpf-event.c:483
> > >     #3 0x557692bbb01a in bpf_event__sb_cb util/bpf-event.c:512
> > >     #4 0x5576928b75f4 in perf_evlist__poll_thread util/sideband_evlist.c:68
> > >     #5 0x7f9df96a63eb in start_thread nptl/pthread_create.c:444
> > >     #6 0x7f9df9726a4b in clone3 ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81
> > >
> > > 0x61d000161e00 is located 384 bytes inside of 2136-byte region [0x61d000161c80,0x61d0001624d8)
> > > freed by thread T0 here:
> > >     #0 0x7f9dfa6d7288 in __interceptor_free libsanitizer/asan/asan_malloc_linux.cpp:52
> > >     #1 0x557692978d50 in perf_session__delete util/session.c:319
> > >     #2 0x557692673959 in __cmd_record tools/perf/builtin-record.c:2884
> > >     #3 0x55769267a9f0 in cmd_record tools/perf/builtin-record.c:4259
> > >     #4 0x55769286710c in run_builtin tools/perf/perf.c:349
> > >     #5 0x557692867678 in handle_internal_command tools/perf/perf.c:402
> > >     #6 0x557692867a40 in run_argv tools/perf/perf.c:446
> > >     #7 0x557692867fae in main tools/perf/perf.c:562
> > >     #8 0x7f9df96456c9 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58
> > > ```
> > >
> > > Fixes: 657ee5531903 ("perf evlist: Introduce side band thread")
> > > Signed-off-by: Ian Rogers <irogers@google.com>
> >
> > Note, after this series I'm seeing parallel perf testing being as
> > reliable as serial but parallel testing is nearly 3 times faster. I
> > think after these changes land we can make parallel execution the
> > default.
> 
> Ping.

Thanks, applied to perf-tools-next,

- Arnaldo