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Date:   Thu, 23 May 2019 16:59:45 +0200
From:   Oleg Nesterov <oleg@redhat.com>
To:     David Laight <David.Laight@ACULAB.COM>
Cc:     'Deepa Dinamani' <deepa.kernel@gmail.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Arnd Bergmann <arnd@arndb.de>,
        "dbueso@suse.de" <dbueso@suse.de>,
        "axboe@kernel.dk" <axboe@kernel.dk>,
        Davidlohr Bueso <dave@stgolabs.net>, Eric Wong <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 <omar.kilani@gmail.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        "stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: Re: [PATCH v2] signal: Adjust error codes according to
 restore_user_sigmask()
Message-ID: <20190523145944.GB23070@redhat.com>
References: <20190522032144.10995-1-deepa.kernel@gmail.com>
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 <20190522161407.GB4915@redhat.com>
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On 05/23, David Laight wrote:
>
> I'm confused...

Me too. To clarify, the current code is obviously buggy, pselect/whatever
shouldn't return 0 (or anything else) if it was interrupted and we are going
to deliver the signal.

But it seems that Deepa has other concerns which I do not understand at all.

In any case, the signal_pending() check _inside_ restore_user_sigmask() can't
be right, with or without this patch. If nothing else, a signal can come right
after the check.

> So epoll() can return 'success' or 'timeout' (etc) and the handler for SIG_URG
> should still be called.

Not sure I understand... OK, suppose that you do

	block-all-signals;
	ret = pselect(..., sigmask(SIG_URG));

if it returns success/timeout then the handler for SIG_URG should not be called?

or I am totally confused...

Oleg.