From: Mark Lord <kernel@teksavvy.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Milton Miller <miltonm@bga.com>, Nick Piggin <npiggin@kernel.dk>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Dipankar Sarma <dipankar@in.ibm.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] fs: synchronize_rcu when unregister_filesystem success not failure
Date: Thu, 14 Apr 2011 20:49:37 -0400 [thread overview]
Message-ID: <4DA79621.5050904@teksavvy.com> (raw)
In-Reply-To: <BANLkTi=Tt8HRmqODM_qPAbGMeQ9UvVDXfA@mail.gmail.com>
On 11-04-14 11:52 AM, Linus Torvalds wrote:
> On Thu, Apr 14, 2011 at 8:41 AM, Milton Miller <miltonm@bga.com> wrote:
>>
>> While checking unregister_filesystem for saftey vs extra calls for
>> "ext4: register ext2 and ext3 alias after ext4" I realized that
>> the synchronize_rcu() was called on the error path but not on
>> the success path.
>
> Good catch.
>
> I think this is the bug that then caused us to do commit d863b50ab013
> ("vfs: call rcu_barrier after ->kill_sb()")
>
> That said, that commit says that "synchronize_rcu()" isn't enough, and
> uses rcu_barrier().
>
> Which _should_ mean that there are no actual users that care about RCU
> events by the time you actually hit "unregister_filesystem()".
Is that true of older kernels? (eg. 2.6.38 has the same bug)
IOW, is this a -stable candidate?
next prev parent reply other threads:[~2011-04-15 0:49 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-12 17:25 CONFIG_EXT4_USE_FOR_EXT23: rootfs shows as ext2 instead of ext4 Mark Lord
2011-04-13 0:49 ` Ted Ts'o
2011-04-13 14:05 ` Mark Lord
2011-04-13 14:10 ` Mark Lord
2011-04-13 21:00 ` Theodore Tso
2011-04-13 22:30 ` Joel Becker
2011-04-14 15:41 ` [PATCH] ext4: register ext2 and ext3 alias after ext4 Milton Miller
2011-04-14 15:41 ` [PATCH] fs: synchronize_rcu when unregister_filesystem success not failure Milton Miller
2011-04-14 15:52 ` Linus Torvalds
2011-04-14 16:59 ` Marco Stornelli
2011-04-15 0:49 ` Mark Lord [this message]
2011-04-15 1:07 ` [PATCH] ext4: register ext2 and ext3 alias after ext4 Mark Lord
2011-04-17 2:01 ` Ted Ts'o
2011-04-14 1:34 ` CONFIG_EXT4_USE_FOR_EXT23: rootfs shows as ext2 instead of ext4 Mark Lord
2011-04-14 12:47 ` Theodore Tso
2011-04-14 12:47 ` Theodore Tso
2011-04-13 16:45 ` John Stoffel
2011-04-13 18:17 ` Ric Wheeler
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