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From: Al Viro <viro@zeniv.linux.org.uk>
To: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: "Pali Rohár" <pali.rohar@gmail.com>,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	"Theodore Y. Ts'o" <tytso@mit.edu>,
	"Namjae Jeon" <linkinjeon@gmail.com>,
	"Gabriel Krisman Bertazi" <krisman@collabora.com>,
	"Linus Torvalds" <torvalds@linux-foundation.org>
Subject: Re: oopsably broken case-insensitive support in ext4 and f2fs (Re: vfat: Broken case-insensitive support for UTF-8)
Date: Mon, 20 Jan 2020 19:35:58 +0000	[thread overview]
Message-ID: <20200120193558.GD8904@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20200120080721.GB8904@ZenIV.linux.org.uk>

On Mon, Jan 20, 2020 at 08:07:21AM +0000, Al Viro wrote:

> > > I hadn't checked ->d_compare() instances for a while; somebody needs to
> > > do that again, by the look of it.  The above definitely is broken;
> > > no idea how many other instaces had grown such bugs...
> > 
> > f2fs one also has the same bug.  Anyway, I'm going down right now, will
> > check the rest tomorrow morning...
> 
> We _probably_ can get away with just checking that inode for NULL and
> buggering off if it is (->d_seq mismatch is guaranteed in that case),
> but I suspect that we might need READ_ONCE() on both dereferences.
> I hate memory barriers...

FWIW, other instances seem to be OK; HFS+ one might or might not be
OK in the face of concurrent rename (wrong result in that case is
no problem; oops would be), but it doesn't play silly buggers with
pointer-chasing.

ext4 and f2fs do, and ->d_compare() is broken in both of them.

  reply	other threads:[~2020-01-20 19:36 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-19 22:14 vfat: Broken case-insensitive support for UTF-8 Pali Rohár
2020-01-19 23:08 ` Al Viro
2020-01-19 23:33   ` Pali Rohár
2020-01-20  0:09     ` Al Viro
2020-01-20 11:19       ` Pali Rohár
2020-01-20  4:04 ` OGAWA Hirofumi
2020-01-20  7:30   ` Al Viro
2020-01-20  7:45     ` Al Viro
2020-01-20  8:07       ` oopsably broken case-insensitive support in ext4 and f2fs (Re: vfat: Broken case-insensitive support for UTF-8) Al Viro
2020-01-20 19:35         ` Al Viro [this message]
2020-01-24  4:29           ` Eric Biggers
2020-01-24 17:47             ` Linus Torvalds
2020-01-24 18:03               ` Jaegeuk Kim
2020-01-24 18:45                 ` Eric Biggers
2020-01-20 11:04   ` vfat: Broken case-insensitive support for UTF-8 Pali Rohár
2020-01-20 12:07     ` OGAWA Hirofumi
2020-01-20 21:40       ` Pali Rohár
2020-01-20 22:46         ` Al Viro
2020-01-20 23:57           ` Pali Rohár
2020-01-21  0:07             ` Al Viro
2020-01-21 20:34               ` Pali Rohár
2020-01-21 21:36                 ` Al Viro
2020-01-21 22:14                   ` Al Viro
2020-01-21 22:46                     ` Pali Rohár
2020-01-26 23:08                 ` Pali Rohár
2020-01-21 12:43             ` David Laight
2020-01-22  0:25         ` Gabriel Krisman Bertazi
2020-01-20 15:07     ` David Laight
2020-01-20 15:20       ` Pali Rohár
2020-01-20 15:47         ` David Laight
2020-01-20 16:12           ` Al Viro
2020-01-20 16:51             ` David Laight
2020-01-20 16:27           ` Pali Rohár
2020-01-20 16:43             ` David Laight
2020-01-20 16:56               ` Pali Rohár
2020-01-20 17:37       ` Theodore Y. Ts'o
2020-01-20 17:32   ` Theodore Y. Ts'o
2020-01-20 17:56     ` Pali Rohár
2020-01-21  3:52     ` OGAWA Hirofumi
2020-01-21 11:00       ` Pali Rohár
2020-01-21 12:26         ` OGAWA Hirofumi

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