linux-kernel - Re: [PATCH v3 16/18] perf sched: Fixes for thread safety analysis

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

Message-ID: <CAM9d7chNUhmULYUfkEuBC3LcD08y7hLGmFn0qeX83KqoPksvCQ@mail.gmail.com>
Date:   Fri, 26 Aug 2022 13:48:09 -0700
From:   Namhyung Kim <namhyung@...nel.org>
To:     Adrian Hunter <adrian.hunter@...el.com>
Cc:     Ian Rogers <irogers@...gle.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@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Darren Hart <dvhart@...radead.org>,
        Davidlohr Bueso <dave@...olabs.net>,
        André Almeida <andrealmeid@...lia.com>,
        Nathan Chancellor <nathan@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Tom Rix <trix@...hat.com>, Weiguo Li <liwg06@...mail.com>,
        Athira Rajeev <atrajeev@...ux.vnet.ibm.com>,
        Thomas Richter <tmricht@...ux.ibm.com>,
        Ravi Bangoria <ravi.bangoria@....com>,
        Dario Petrillo <dario.pk1@...il.com>,
        Hewenliang <hewenliang4@...wei.com>,
        yaowenbin <yaowenbin1@...wei.com>,
        Wenyu Liu <liuwenyu7@...wei.com>,
        Song Liu <songliubraving@...com>,
        Andrii Nakryiko <andrii@...nel.org>,
        Dave Marchevsky <davemarchevsky@...com>,
        Leo Yan <leo.yan@...aro.org>,
        Kim Phillips <kim.phillips@....com>,
        Pavithra Gurushankar <gpavithrasha@...il.com>,
        Alexandre Truong <alexandre.truong@....com>,
        Quentin Monnet <quentin@...valent.com>,
        William Cohen <wcohen@...hat.com>,
        Andres Freund <andres@...razel.de>,
        Martin Liška <mliska@...e.cz>,
        Colin Ian King <colin.king@...el.com>,
        James Clark <james.clark@....com>,
        Fangrui Song <maskray@...gle.com>,
        Stephane Eranian <eranian@...gle.com>,
        Kajol Jain <kjain@...ux.ibm.com>,
        Alexey Bayduraev <alexey.v.bayduraev@...ux.intel.com>,
        Riccardo Mancini <rickyman7@...il.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Zechuan Chen <chenzechuan1@...wei.com>,
        Jason Wang <wangborong@...rlc.com>,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        Remi Bernon <rbernon@...eweavers.com>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        linux-perf-users <linux-perf-users@...r.kernel.org>,
        bpf <bpf@...r.kernel.org>, llvm@...ts.linux.dev
Subject: Re: [PATCH v3 16/18] perf sched: Fixes for thread safety analysis

On Fri, Aug 26, 2022 at 12:36 PM Adrian Hunter <adrian.hunter@...el.com> wrote:
>
> On 26/08/22 21:26, Namhyung Kim wrote:
> > On Fri, Aug 26, 2022 at 10:48 AM Ian Rogers <irogers@...gle.com> wrote:

> >> In the previous code the threads were blocked on mutexes that were
> >> stack allocated and the stack memory went away. You are correct to say
> >> that to those locks I added an init and destroy call. The lifetime of
> >> the mutex was wrong previously and remains wrong in this change.
> >
> > I think you fixed the lifetime issue with sched->thread_funcs_exit here.
> > All you need to do is calling pthread_join() after the mutex_unlock, no?
>
> Like this maybe:

Yeah, but at this point we might want to factor it out as a function like
destroy_tasks().

Thanks,
Namhyung

>
> diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
> index b483ff0d432e..8090c1218855 100644
> --- a/tools/perf/builtin-sched.c
> +++ b/tools/perf/builtin-sched.c
> @@ -3326,6 +3326,13 @@ static int perf_sched__replay(struct perf_sched *sched)
>         sched->thread_funcs_exit = true;
>         mutex_unlock(&sched->start_work_mutex);
>         mutex_unlock(&sched->work_done_wait_mutex);
> +       /* Get rid of threads so they won't be upset by mutex destruction */
> +       for (i = 0; i < sched->nr_tasks; i++) {
> +               int err = pthread_join(sched->tasks[i]->thread, NULL);
> +
> +               if (err)
> +                       pr_err("pthread_join() failed for task nr %lu, error %d\n", i, err);
> +       }
>         return 0;
>  }