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Date:   Wed, 31 Mar 2021 16:51:08 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Marco Elver <elver@google.com>
Cc:     Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Ingo Molnar <mingo@redhat.com>, Jiri Olsa <jolsa@redhat.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Namhyung Kim <namhyung@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Alexander Potapenko <glider@google.com>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Arnd Bergmann <arnd@arndb.de>,
        Christian Brauner <christian@brauner.io>,
        Dmitry Vyukov <dvyukov@google.com>,
        Jann Horn <jannh@google.com>, Jens Axboe <axboe@kernel.dk>,
        Matt Morehouse <mascasa@google.com>,
        Peter Collingbourne <pcc@google.com>,
        Ian Rogers <irogers@google.com>,
        kasan-dev <kasan-dev@googlegroups.com>,
        linux-arch <linux-arch@vger.kernel.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        the arch/x86 maintainers <x86@kernel.org>,
        "open list:KERNEL SELFTEST FRAMEWORK" 
        <linux-kselftest@vger.kernel.org>, Oleg Nesterov <oleg@redhat.com>,
        Jiri Olsa <jolsa@kernel.org>
Subject: Re: [PATCH v3 06/11] perf: Add support for SIGTRAP on perf events
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On Wed, Mar 31, 2021 at 02:32:58PM +0200, Marco Elver wrote:
> On Mon, 29 Mar 2021 at 14:07, Peter Zijlstra <peterz@infradead.org> wrote:
> 
> > (and we might already have a problem on some architectures where there
> > can be significant time between these due to not having
> > arch_irq_work_raise(), so ideally we ought to double check current in
> > your case)
> 
> I missed this bit -- just to verify: here we want to check that
> event->ctx->task == current, in case the the irq_work runs when the
> current task has already been replaced. Correct?

Yeah, just not sure what a decent failure would be, silent ignore seems
undesired, maybe WARN and archs that can trigger it get to fix it ?