From: Philipp Reisner <philipp.reisner@linbit.com>
To: David Laight <David.Laight@aculab.com>
Cc: "Jens Axboe" <axboe@kernel.dk>,
"'Christoph Böhmwalder'" <christoph.boehmwalder@linbit.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"stable@vger.kernel.org" <stable@vger.kernel.org>,
"Eric W . Biederman" <ebiederm@xmission.com>
Subject: Re: [PATCH] drbd: do not ignore signals in threads
Date: Mon, 12 Aug 2019 15:28:40 +0200 [thread overview]
Message-ID: <2789113.VEJ2NpTmzX@fat-tyre> (raw)
In-Reply-To: <1fcbb94c5f264c17af3394807438ad50@AcuMS.aculab.com>
Hi David,
[...]
> While our code is 'out of tree' (you really don't want it - and since
> it still uses force_sig() is fine) I suspect that the 'drdb' code
> (with Christoph's allow_signal() patch) now loops in kernel if a user
> sends it a signal.
I am not asking for that out of tree code. But you are welcome to learn
from the drbd code that is in the upstream kernel.
It does not loop if a root sends a signal, it receives it and ignores it.
> If the driver (eg drdb) is using (say) SIGINT to break a thread out of
> (say) a blocking kernel_accept() call then it can detect the unexpected
> signal (maybe double-checking with signal_pending()) but I don't think
> it can clear down the pending signal so that kernel_accept() blocks
> again.
You do that with flush_signals(current)
What we have do is, somewhere in the main loop:
if (signal_pending(current)) {
flush_signals(current);
if (!terminate_condition()) {
warn(connection, "Ignoring an unexpected signal\n");
continue;
}
break;
}
}
--
LINBIT | Keeping The Digital World Running
DRBD® and LINBIT® are registered trademarks of LINBIT, Austria.
next prev parent reply other threads:[~2019-08-12 13:28 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-29 8:32 [PATCH] drbd: do not ignore signals in threads Christoph Böhmwalder
2019-07-29 8:50 ` David Laight
2019-08-05 9:33 ` Christoph Böhmwalder
2019-08-05 9:41 ` David Laight
2019-08-12 11:52 ` Philipp Reisner
2019-08-12 13:12 ` David Laight
2019-08-12 13:28 ` Philipp Reisner [this message]
2019-08-16 22:19 ` [PATCH] signal: Allow cifs and drbd to receive their terminating signals Eric W. Biederman
2019-08-19 8:37 ` Christoph Böhmwalder
2019-08-19 22:03 ` [GIT PULL] " Eric W. Biederman
2019-08-19 23:35 ` pr-tracker-bot
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