[Bug 27972] New: Null pointer dereference at shutdown time

[Bug 27972] New: Null pointer dereference at shutdown time

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=27972

           Summary: Null pointer dereference at shutdown time
           Product: File System
           Version: 2.5
    Kernel Version: Linux pluto.afaics.de 2.6.37 #1 SMP PREEMPT Thu Jan 20
                    20:29:44 CET 2011 x86_64 GNU/Linux
          Platform: All
        OS/Version: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: ReiserFS
        AssignedTo: reiserfs-devel@vger.kernel.org
        ReportedBy: harri@afaics.de
        Regression: No


Created an attachment (id=45722)
 --> (https://bugzilla.kernel.org/attachment.cgi?id=45722)
screen snapshot

I got a kernel dump at umount time of a huge reiserfs partition. It said

    Null pointer dereference at 0000000000000010
    IP: [ffffffffa01dc818] open_xa_dir+0x2d/0x1b0 [reiserfs]
    :

The config file and a photo with a complete stack trace are attached.

reiserfsck of this partition showed a lot of files to sync due to the missing
umount, but no other problems.

Kernel is 2.6.37 (amd64). Please mail if I can help to track this
down.

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[Bug 27972] Null pointer dereference at shutdown time

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=27972





--- Comment #1 from Harald Dunkel <harri@afaics.de>  2011-02-01 04:55:27 ---
Created an attachment (id=45732)
 --> (https://bugzilla.kernel.org/attachment.cgi?id=45732)
config file

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[Bug 27972] Null pointer dereference at shutdown time

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=27972





--- Comment #2 from Jeff Mahoney <jeffm@suse.com>  2011-02-02 15:54:19 ---
Created an attachment (id=46052)
 --> (https://bugzilla.kernel.org/attachment.cgi?id=46052)
reiserfs: Fix crash during umount

 There is a conflict between shrink_dcache_for_umount_subtree and how
 xattrs are cleaned up for deleted files at umount.

 shrink_dcache_for_umount_subtree wants to ensure that all dentries for a
 file system have been evicted and it walks the dentry tree from the root
 of the file system to do this. It will BUG if there are any dentries
 left with elevated counts.

 The reiserfs xattr infrastructure caches two dentries. One is for
 .reiserfs_priv and the other is for .reiserfs_priv/xattrs. When
 shrink_dcache_for_umount_subtree goes through, it will BUG on these dentries
 if they aren't freed. OTOH, it will Oops in reiserfs_delete_xattrs if
 they are due to the xattr code needing to walk the list of xattrs for
 a file undergoing delayed deletion. This will end up loading up other
 dentries and possibly queue up more delayed deletions.

 This patch detaches the tree under .reiserfs_priv during ->kill_sb. This
 allows shrink_dcache_for_umount_subtree to complete successfully as well
 as keeps around the .reiserfs_priv tree for deletion handling. After
 the regular cycle is completed, it will call shrink_dcache_for_umount_subtree
 again itself to ensure that the xattrs are cleaned up.

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[Bug 27972] Null pointer dereference at shutdown time

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https://bugzilla.kernel.org/show_bug.cgi?id=27972


Alan <alan@lxorguk.ukuu.org.uk> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |alan@lxorguk.ukuu.org.uk
     Kernel Version|Linux pluto.afaics.de       |2.6.37  x86_64
                   |2.6.37 #1 SMP PREEMPT Thu   |
                   |Jan 20 20:29:44 CET 2011    |
                   |x86_64 GNU/Linux            |




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[Bug 27972] Null pointer dereference at shutdown time

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https://bugzilla.kernel.org/show_bug.cgi?id=27972


Alan <alan@lxorguk.ukuu.org.uk> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |CODE_FIX




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