linux-ext4 - [Bug 15792] ext4_inode_inode->i

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <201004152231.o3FMVwAT001332@demeter.kernel.org>
Date:	Thu, 15 Apr 2010 22:31:58 GMT
From:	bugzilla-daemon@...zilla.kernel.org
To:	linux-ext4@...r.kernel.org
Subject: [Bug 15792] ext4_inode_inode->i_flags modification is racy

https://bugzilla.kernel.org/show_bug.cgi?id=15792





--- Comment #2 from Dmitry Monakhov <dmonakhov@...nvz.org>  2010-04-15 22:31:55 ---
The oops happens because non tested branch was triggered.
./fs/ext4/extents.c
3477:    if (unlikely(EXT4_I(inode)->i_flags & EXT4_EOFBLOCKS_FL)) {
                if (unlikely(!eh->eh_entries)) {
                        EXT4_ERROR_INODE(inode,
                                         "eh->eh_entries == 0 ee_block %d",
                                         ex->ee_block);
### OOPS here because ex == NULL ^^^^^^^^^^^^^^^^^^^^^^^^
                        err = -EIO;
                        goto out2;
                }

Bug was introduced by following commit:
commit 273df556b6ee2065bfe96edab5888d3dc9b108d8
Author: Frank Mayhar <fmayhar@...gle.com>
Date:   Tue Mar 2 11:46:09 2010 -0500

And in fact it is rather trivial to fix.
But most interesting question what the hell we are doing on that error path?
inode has EXT4_EOFBLOCKS_FL flag enabled but eh->eh_entries, and in fact
after adding more debug information i've found that inode is simply blockless.
i_blocks == 0, i_size == 0.

I've collected per-inode i_flag modification history (see an attachment)

-- 
Configure bugmail: https://bugzilla.kernel.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are watching the assignee of the bug.
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html