From: Al Viro <viro@ZenIV.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Nick Piggin <npiggin@kernel.dk>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
neilb@suse.de
Subject: Re: [PATCH] vfs: fix race in rcu lookup of pruned dentry
Date: Wed, 20 Jul 2011 00:52:16 +0100 [thread overview]
Message-ID: <20110719235215.GS11013@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20110719234550.GR11013@ZenIV.linux.org.uk>
On Wed, Jul 20, 2011 at 12:45:51AM +0100, Al Viro wrote:
> You know what... I doubt that you want to mess with ->d_seq checks here.
> It's definitely not Hugh's bug (unless he has bindings somewhere odd) and
> both ->mnt_mountpoint and ->mnt_root are pinned (and we are holding
> vfsmount_lock anyway). *inode assignment too early is a real bug, indeed,
> and we want to assign nd->seq if we cross mountpoint as both versions do,
> but check just before that is, in the best case, BUG_ON() fodder. We'd
> just found a vfsmount with ->mnt_mountpoint equal to path->dentry; it *can't*
> be stale, or we have a really nasty problem anyway.
Kudos to neilb for spotting the pointless check, BTW; and no, his theory
that it might be needed since we could race with umount() is wrong - due to
vfsmount_lock being held.
next prev parent reply other threads:[~2011-07-19 23:52 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-17 21:03 [PATCH] vfs: fix race in rcu lookup of pruned dentry Hugh Dickins
2011-07-17 22:00 ` Linus Torvalds
2011-07-17 22:59 ` Linus Torvalds
2011-07-17 23:26 ` Al Viro
2011-07-17 23:16 ` Al Viro
2011-07-17 23:38 ` Linus Torvalds
2011-07-17 23:47 ` Hugh Dickins
2011-07-18 0:25 ` Al Viro
2011-07-18 1:13 ` Hugh Dickins
2011-07-18 2:08 ` Al Viro
2011-07-18 6:31 ` Linus Torvalds
2011-07-18 6:31 ` Linus Torvalds
2011-07-18 14:41 ` Hugh Dickins
2011-07-18 18:11 ` Linus Torvalds
2011-07-18 18:20 ` Al Viro
2011-07-18 19:08 ` Linus Torvalds
2011-07-18 19:20 ` Al Viro
2011-07-18 19:23 ` Al Viro
2011-07-18 19:34 ` Linus Torvalds
2011-07-18 19:04 ` Hugh Dickins
2011-07-18 19:33 ` Linus Torvalds
2011-07-18 19:47 ` Al Viro
2011-07-18 20:24 ` Linus Torvalds
2011-07-18 21:19 ` Hugh Dickins
2011-07-18 21:42 ` Linus Torvalds
2011-07-18 22:43 ` Hugh Dickins
2011-07-18 23:17 ` Al Viro
2011-07-18 23:21 ` Al Viro
2011-07-18 23:27 ` Linus Torvalds
2011-07-18 23:40 ` Al Viro
2011-07-19 2:07 ` Hugh Dickins
2011-07-19 2:14 ` Linus Torvalds
2011-07-19 2:14 ` Linus Torvalds
2011-07-19 2:17 ` Linus Torvalds
2011-07-19 2:23 ` Al Viro
2011-07-19 2:37 ` Chris Ball
2011-07-19 4:41 ` Nicolas Pitre
2011-07-19 2:21 ` Al Viro
2011-07-19 23:45 ` Al Viro
2011-07-19 23:52 ` Al Viro [this message]
2011-07-19 23:55 ` Al Viro
2011-07-20 0:47 ` NeilBrown
2011-07-20 1:40 ` Al Viro
2011-07-20 4:52 ` Linus Torvalds
2011-07-20 4:52 ` Linus Torvalds
2011-07-19 23:56 ` Linus Torvalds
2011-07-20 0:04 ` Al Viro
2011-07-17 23:53 ` Al Viro
2011-07-17 23:31 ` Hugh Dickins
2011-07-17 23:52 ` Linus Torvalds
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