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From: Jens Axboe <axboe@kernel.dk>
To: Hannes Reinecke <hare@suse.de>,
	"Martin K. Petersen" <martin.petersen@oracle.com>
Cc: James Bottomley <james.bottomley@hansenpartnership.com>,
	Doug Gilbert <dgilbert@interlog.com>,
	linux-scsi@vger.kernel.org, Ewan Milne <emilne@redhat.com>,
	linux-block@vger.kernel.org,
	Johannes Thumshirn <jthumshirn@suse.de>,
	stable@vger.kernel.org, #@suse.de, v.3.11+@suse.de
Subject: Re: [PATCH] bio: return EINTR if copying to user space got interrupted
Date: Fri, 12 Feb 2016 08:17:58 -0700	[thread overview]
Message-ID: <56BDF7A6.8070207@kernel.dk> (raw)
In-Reply-To: <1455266355-44676-1-git-send-email-hare@suse.de>

On 02/12/2016 01:39 AM, Hannes Reinecke wrote:
> Commit 35dc248383bbab0a7203fca4d722875bc81ef091 introduced a check for
> current->mm to see if we have a user space context and only copies data
> if we do. Now if an IO gets interrupted by a signal data isn't copied
> into user space any more (as we don't have a user space context) but
> user space isn't notified about it.
>
> This patch modifies the behaviour to return -EINTR from bio_uncopy_user()
> to notify userland that a signal has interrupted the syscall, otherwise
> it could lead to a situation where the caller may get a buffer with
> no data returned.
>
> This can be reproduced by issuing SG_IO ioctl()s in one thread while
> constantly sending signals to it.

Good catch, fix looks good to me. Applied for 4.5.

-- 
Jens Axboe


  reply	other threads:[~2016-02-12 15:18 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-12  8:39 [PATCH] bio: return EINTR if copying to user space got interrupted Hannes Reinecke
2016-02-12 15:17 ` Jens Axboe [this message]
2016-02-12 16:05 ` Douglas Gilbert
2016-02-12 16:14   ` Hannes Reinecke
2016-02-12 16:15 ` Ewan Milne

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