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From: Martin Brandenburg <martin@omnibond.com>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Mike Marshall <hubcap@omnibond.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: Orangefs ABI documentation
Date: Tue, 26 Jan 2016 14:52:23 -0500	[thread overview]
Message-ID: <CA+D=wkjuAq-krCKPMFJ6M4iik4Cz=WLS1KE=pQQGSWpz07q6Rw@mail.gmail.com> (raw)
In-Reply-To: <20160124040529.GX17997@ZenIV.linux.org.uk>

On 1/23/16, Al Viro <viro@zeniv.linux.org.uk> wrote:
> We'll just decrement the refcount of bufmap, do nothing since it hasn't
> reached zero, proceed to mark all ops as purged, wake each service_operation()
> up and sod off.  Now, the holders of those slots will call
> orangefs_get_bufmap_init(), get 1 (since we hadn't dropped the last reference
> yet - can it *ever* see 0 there, actually?) and return -EAGAIN.  With
> wait_for_direct_io() noticing that, freeing the slot and going into restart.
> And if there was the only one, we are fine, but what if there were several?

The answer here is yes. Otherwise a malicious client could not set up
the bufmap then crash the kernel by attempting to use it.

-- Martin

  parent reply	other threads:[~2016-01-26 19:52 UTC|newest]

Thread overview: 111+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-15 21:46 Orangefs ABI documentation Mike Marshall
2016-01-22  7:11 ` Al Viro
2016-01-22 11:09   ` Mike Marshall
2016-01-22 16:59     ` Mike Marshall
2016-01-22 17:08       ` Al Viro
2016-01-22 17:40         ` Mike Marshall
2016-01-22 17:43         ` Al Viro
2016-01-22 18:17           ` Mike Marshall
2016-01-22 18:37             ` Al Viro
2016-01-22 19:07               ` Mike Marshall
2016-01-22 19:21                 ` Mike Marshall
2016-01-22 20:04                   ` Al Viro
2016-01-22 20:30                     ` Mike Marshall
2016-01-23  0:12                       ` Al Viro
2016-01-23  1:28                         ` Al Viro
2016-01-23  2:54                           ` Mike Marshall
2016-01-23 19:10                             ` Al Viro
2016-01-23 19:24                               ` Mike Marshall
2016-01-23 21:35                                 ` Mike Marshall
2016-01-23 22:05                                   ` Al Viro
2016-01-23 21:40                                 ` Al Viro
2016-01-23 22:36                                   ` Mike Marshall
2016-01-24  0:16                                     ` Al Viro
2016-01-24  4:05                                       ` Al Viro
2016-01-24 22:12                                         ` Mike Marshall
2016-01-30 17:22                                           ` Al Viro
2016-01-26 19:52                                         ` Martin Brandenburg [this message]
2016-01-30 17:34                                           ` Al Viro
2016-01-30 18:27                                             ` Al Viro
2016-02-04 23:30                                               ` Mike Marshall
2016-02-06 19:42                                                 ` Al Viro
2016-02-07  1:38                                                   ` Al Viro
2016-02-07  3:53                                                     ` Al Viro
2016-02-07 20:01                                                       ` [RFC] bufmap-related wait logics (Re: Orangefs ABI documentation) Al Viro
2016-02-08 22:26                                                       ` Orangefs ABI documentation Mike Marshall
2016-02-08 23:35                                                         ` Al Viro
2016-02-09  3:32                                                           ` Al Viro
2016-02-09 14:34                                                             ` Mike Marshall
2016-02-09 17:40                                                               ` Al Viro
2016-02-09 21:06                                                                 ` Al Viro
2016-02-09 22:25                                                                   ` Mike Marshall
2016-02-11 23:36                                                                   ` Mike Marshall
2016-02-09 22:02                                                                 ` Mike Marshall
2016-02-09 22:16                                                                   ` Al Viro
2016-02-09 22:40                                                                     ` Al Viro
2016-02-09 23:13                                                                       ` Al Viro
2016-02-10 16:44                                                                         ` Al Viro
2016-02-10 21:26                                                                           ` Al Viro
2016-02-11 23:54                                                                           ` Mike Marshall
2016-02-12  0:55                                                                             ` Al Viro
2016-02-12 12:13                                                                               ` Mike Marshall
2016-02-11  0:44                                                                         ` Al Viro
2016-02-11  3:22                                                                           ` Mike Marshall
2016-02-12  4:27                                                                             ` Al Viro
2016-02-12 12:26                                                                               ` Mike Marshall
2016-02-12 18:00                                                                                 ` Martin Brandenburg
2016-02-13 17:18                                                                                   ` Mike Marshall
2016-02-13 17:47                                                                                     ` Al Viro
2016-02-14  2:56                                                                                       ` Al Viro
2016-02-14  3:46                                                                                         ` [RFC] slot allocator - waitqueue use review needed (Re: Orangefs ABI documentation) Al Viro
2016-02-14  4:06                                                                                           ` Al Viro
2016-02-16  2:12                                                                                           ` Al Viro
2016-02-16 19:28                                                                                             ` Al Viro
2016-02-14 22:31                                                                                         ` Orangefs ABI documentation Mike Marshall
2016-02-14 23:43                                                                                           ` Al Viro
2016-02-15 17:46                                                                                             ` Mike Marshall
2016-02-15 18:45                                                                                               ` Al Viro
2016-02-15 22:32                                                                                                 ` Martin Brandenburg
2016-02-15 23:04                                                                                                   ` Al Viro
2016-02-16 23:15                                                                                                     ` Mike Marshall
2016-02-16 23:36                                                                                                       ` Al Viro
2016-02-16 23:54                                                                                                         ` Al Viro
2016-02-17 19:24                                                                                                           ` Mike Marshall
2016-02-17 20:11                                                                                                             ` Al Viro
2016-02-17 21:17                                                                                                               ` Al Viro
2016-02-17 22:24                                                                                                                 ` Mike Marshall
2016-02-17 22:40                                                                                                             ` Martin Brandenburg
2016-02-17 23:09                                                                                                               ` Al Viro
2016-02-17 23:15                                                                                                                 ` Al Viro
2016-02-18  0:04                                                                                                                   ` Al Viro
2016-02-18 11:11                                                                                                                     ` Al Viro
2016-02-18 18:58                                                                                                                       ` Mike Marshall
2016-02-18 19:20                                                                                                                         ` Al Viro
2016-02-18 19:49                                                                                                                         ` Martin Brandenburg
2016-02-18 20:08                                                                                                                           ` Mike Marshall
2016-02-18 20:22                                                                                                                             ` Mike Marshall
2016-02-18 20:38                                                                                                                               ` Mike Marshall
2016-02-18 20:52                                                                                                                                 ` Al Viro
2016-02-18 21:50                                                                                                                                   ` Mike Marshall
2016-02-19  0:25                                                                                                                                     ` Al Viro
2016-02-19 22:11                                                                                                                                       ` Mike Marshall
2016-02-19 22:22                                                                                                                                         ` Al Viro
2016-02-20 12:14                                                                                                                                           ` Mike Marshall
2016-02-20 13:36                                                                                                                                             ` Al Viro
2016-02-22 16:20                                                                                                                                               ` Mike Marshall
2016-02-22 21:22                                                                                                                                                 ` Mike Marshall
2016-02-23 21:58                                                                                                                                                   ` Mike Marshall
2016-02-26 20:21                                                                                                                                                     ` Mike Marshall
2016-02-19 22:32                                                                                                                                         ` Al Viro
2016-02-19 22:45                                                                                                                                           ` Martin Brandenburg
2016-02-19 22:50                                                                                                                                           ` Martin Brandenburg
2016-02-18 20:49                                                                                                                               ` Al Viro
2016-02-15 22:47                                                                                                 ` Mike Marshall
2016-01-23 22:46                                   ` write() semantics (Re: Orangefs ABI documentation) Al Viro
2016-01-23 23:35                                     ` Linus Torvalds
2016-03-03 22:25                                       ` Mike Marshall
2016-03-04 20:55                                         ` Mike Marshall
2016-01-22 20:51                     ` Orangefs ABI documentation Mike Marshall
2016-01-22 23:53                       ` Mike Marshall
2016-01-22 19:54                 ` Al Viro
2016-01-22 19:50             ` Al Viro

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