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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Tue, 4 Jun 2019 18:37:26 +0200
Message-ID: <CAK8P3a3Dv+hqnQHWU2nG5rB+hGrqbcDC3DUoNGZAzNGJgJwizA@mail.gmail.com>
Subject: Re: [PATCH] signal: remove the wrong signal_pending() check in restore_user_sigmask()
To:     Oleg Nesterov <oleg@redhat.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Deepa Dinamani <deepa.kernel@gmail.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        dbueso@suse.de, Jens Axboe <axboe@kernel.dk>,
        Davidlohr Bueso <dave@stgolabs.net>, e@80x24.org,
        Jason Baron <jbaron@akamai.com>,
        Linux FS-devel Mailing List <linux-fsdevel@vger.kernel.org>,
        linux-aio <linux-aio@kvack.org>, omar.kilani@gmail.com,
        Thomas Gleixner <tglx@linutronix.de>,
        "# 3.4.x" <stable@vger.kernel.org>,
        Al Viro <viro@zeniv.linux.org.uk>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        David Laight <David.Laight@aculab.com>
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On Tue, Jun 4, 2019 at 3:41 PM Oleg Nesterov <oleg@redhat.com> wrote:
>
> This is the minimal fix for stable, I'll send cleanups later.
>
> The commit 854a6ed56839a40f6b5d02a2962f48841482eec4 ("signal: Add
> restore_user_sigmask()") introduced the visible change which breaks
> user-space: a signal temporary unblocked by set_user_sigmask() can
> be delivered even if the caller returns success or timeout.
>
> Change restore_user_sigmask() to accept the additional "interrupted"
> argument which should be used instead of signal_pending() check, and
> update the callers.
>
> Reported-by: Eric Wong <e@80x24.org>
> Fixes: 854a6ed56839a40f6b5d02a2962f48841482eec4 ("signal: Add restore_user_sigmask()")
> cc: stable@vger.kernel.org (v5.0+)
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>

Acked-by: Arnd Bergmann <arnd@arndb.de>

I hope Eric can test this with the original reproducer, or maybe someone
could create a test case that can be added into LTP.

      Arnd