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From: Greg KH <gregkh@suse.de>
To: linux-kernel@vger.kernel.org, stable@kernel.org
Cc: stable-review@kernel.org, torvalds@linux-foundation.org,
	akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk,
	"Theodore Tso" <tytso@mit.edu>,
	Greg Kroah-Hartman <gregkh@suse.de>
Subject: [34/34] ext4: Fix potential fiemap deadlock (mmap_sem vs. i_data_sem)
Date: Thu, 10 Dec 2009 21:23:46 -0800	[thread overview]
Message-ID: <20091211052558.863762484@linux.site> (raw)
In-Reply-To: <20091211052858.GA23229@kroah.com>

[-- Attachment #1: 0030-ext4-Fix-potential-fiemap-deadlock-mmap_sem-vs.-i_da.patch --]
[-- Type: text/plain, Size: 5130 bytes --]

2.6.32-stable review patch.  If anyone has any objections, please let us know.

------------------

(cherry picked from commit fab3a549e204172236779f502eccb4f9bf0dc87d)

Fix the following potential circular locking dependency between
mm->mmap_sem and ei->i_data_sem:

    =======================================================
    [ INFO: possible circular locking dependency detected ]
    2.6.32-04115-gec044c5 #37
    -------------------------------------------------------
    ureadahead/1855 is trying to acquire lock:
     (&mm->mmap_sem){++++++}, at: [<ffffffff81107224>] might_fault+0x5c/0xac

    but task is already holding lock:
     (&ei->i_data_sem){++++..}, at: [<ffffffff811be1fd>] ext4_fiemap+0x11b/0x159

    which lock already depends on the new lock.

    the existing dependency chain (in reverse order) is:

    -> #1 (&ei->i_data_sem){++++..}:
           [<ffffffff81099bfa>] __lock_acquire+0xb67/0xd0f
           [<ffffffff81099e7e>] lock_acquire+0xdc/0x102
           [<ffffffff81516633>] down_read+0x51/0x84
           [<ffffffff811a2414>] ext4_get_blocks+0x50/0x2a5
           [<ffffffff811a3453>] ext4_get_block+0xab/0xef
           [<ffffffff81154f39>] do_mpage_readpage+0x198/0x48d
           [<ffffffff81155360>] mpage_readpages+0xd0/0x114
           [<ffffffff811a104b>] ext4_readpages+0x1d/0x1f
           [<ffffffff810f8644>] __do_page_cache_readahead+0x12f/0x1bc
           [<ffffffff810f86f2>] ra_submit+0x21/0x25
           [<ffffffff810f0cfd>] filemap_fault+0x19f/0x32c
           [<ffffffff81107b97>] __do_fault+0x55/0x3a2
           [<ffffffff81109db0>] handle_mm_fault+0x327/0x734
           [<ffffffff8151aaa9>] do_page_fault+0x292/0x2aa
           [<ffffffff81518205>] page_fault+0x25/0x30
           [<ffffffff812a34d8>] clear_user+0x38/0x3c
           [<ffffffff81167e16>] padzero+0x20/0x31
           [<ffffffff81168b47>] load_elf_binary+0x8bc/0x17ed
           [<ffffffff81130e95>] search_binary_handler+0xc2/0x259
           [<ffffffff81166d64>] load_script+0x1b8/0x1cc
           [<ffffffff81130e95>] search_binary_handler+0xc2/0x259
           [<ffffffff8113255f>] do_execve+0x1ce/0x2cf
           [<ffffffff81027494>] sys_execve+0x43/0x5a
           [<ffffffff8102918a>] stub_execve+0x6a/0xc0

    -> #0 (&mm->mmap_sem){++++++}:
           [<ffffffff81099aa4>] __lock_acquire+0xa11/0xd0f
           [<ffffffff81099e7e>] lock_acquire+0xdc/0x102
           [<ffffffff81107251>] might_fault+0x89/0xac
           [<ffffffff81139382>] fiemap_fill_next_extent+0x95/0xda
           [<ffffffff811bcb43>] ext4_ext_fiemap_cb+0x138/0x157
           [<ffffffff811be069>] ext4_ext_walk_space+0x178/0x1f1
           [<ffffffff811be21e>] ext4_fiemap+0x13c/0x159
           [<ffffffff811390e6>] do_vfs_ioctl+0x348/0x4d6
           [<ffffffff811392ca>] sys_ioctl+0x56/0x79
           [<ffffffff81028cb2>] system_call_fastpath+0x16/0x1b

    other info that might help us debug this:

    1 lock held by ureadahead/1855:
     #0:  (&ei->i_data_sem){++++..}, at: [<ffffffff811be1fd>] ext4_fiemap+0x11b/0x159

    stack backtrace:
    Pid: 1855, comm: ureadahead Not tainted 2.6.32-04115-gec044c5 #37
    Call Trace:
     [<ffffffff81098c70>] print_circular_bug+0xa8/0xb7
     [<ffffffff81099aa4>] __lock_acquire+0xa11/0xd0f
     [<ffffffff8102f229>] ? sched_clock+0x9/0xd
     [<ffffffff81099e7e>] lock_acquire+0xdc/0x102
     [<ffffffff81107224>] ? might_fault+0x5c/0xac
     [<ffffffff81107251>] might_fault+0x89/0xac
     [<ffffffff81107224>] ? might_fault+0x5c/0xac
     [<ffffffff81124b44>] ? __kmalloc+0x13b/0x18c
     [<ffffffff81139382>] fiemap_fill_next_extent+0x95/0xda
     [<ffffffff811bcb43>] ext4_ext_fiemap_cb+0x138/0x157
     [<ffffffff811bca0b>] ? ext4_ext_fiemap_cb+0x0/0x157
     [<ffffffff811be069>] ext4_ext_walk_space+0x178/0x1f1
     [<ffffffff811be21e>] ext4_fiemap+0x13c/0x159
     [<ffffffff81107224>] ? might_fault+0x5c/0xac
     [<ffffffff811390e6>] do_vfs_ioctl+0x348/0x4d6
     [<ffffffff8129f6d0>] ? __up_read+0x8d/0x95
     [<ffffffff81517fb5>] ? retint_swapgs+0x13/0x1b
     [<ffffffff811392ca>] sys_ioctl+0x56/0x79
     [<ffffffff81028cb2>] system_call_fastpath+0x16/0x1b

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 fs/ext4/extents.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -1761,7 +1761,9 @@ int ext4_ext_walk_space(struct inode *in
 	while (block < last && block != EXT_MAX_BLOCK) {
 		num = last - block;
 		/* find extent for this block */
+		down_read(&EXT4_I(inode)->i_data_sem);
 		path = ext4_ext_find_extent(inode, block, path);
+		up_read(&EXT4_I(inode)->i_data_sem);
 		if (IS_ERR(path)) {
 			err = PTR_ERR(path);
 			path = NULL;
@@ -3730,10 +3732,8 @@ int ext4_fiemap(struct inode *inode, str
 		 * Walk the extent tree gathering extent information.
 		 * ext4_ext_fiemap_cb will push extents back to user.
 		 */
-		down_read(&EXT4_I(inode)->i_data_sem);
 		error = ext4_ext_walk_space(inode, start_blk, len_blks,
 					  ext4_ext_fiemap_cb, fieinfo);
-		up_read(&EXT4_I(inode)->i_data_sem);
 	}
 
 	return error;



      parent reply	other threads:[~2009-12-11  5:30 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20091211052312.805428372@linux.site>
2009-12-11  5:28 ` [00/34] 2.6.32.1-stable review Greg KH
2009-12-11  5:23   ` [01/34] signal: Fix alternate signal stack check Greg KH
2009-12-11  5:23   ` [02/34] SCSI: scsi_lib_dma: fix bug with dma maps on nested scsi objects Greg KH
2009-12-11  5:23   ` [03/34] SCSI: osd_protocol.h: Add missing #include Greg KH
2009-12-11  5:23   ` [04/34] SCSI: megaraid_sas: fix 64 bit sense pointer truncation Greg KH
2009-12-11  5:23   ` [05/34] ext4: fix potential buffer head leak when add_dirent_to_buf() returns ENOSPC Greg KH
2009-12-11  5:23   ` [06/34] ext4: avoid divide by zero when trying to mount a corrupted file system Greg KH
2009-12-11  5:23   ` [07/34] ext4: fix the returned block count if EXT4_IOC_MOVE_EXT fails Greg KH
2009-12-11  5:23   ` [08/34] ext4: fix lock order problem in ext4_move_extents() Greg KH
2009-12-11  5:23   ` [09/34] ext4: fix possible recursive locking warning in EXT4_IOC_MOVE_EXT Greg KH
2009-12-11  5:23   ` [10/34] ext4: plug a buffer_head leak in an error path of ext4_iget() Greg KH
2009-12-11  5:23   ` [11/34] ext4: make sure directory and symlink blocks are revoked Greg KH
2009-12-11  5:23   ` [12/34] ext4: fix i_flags access in ext4_da_writepages_trans_blocks() Greg KH
2009-12-11  5:23   ` [13/34] ext4: journal all modifications in ext4_xattr_set_handle Greg KH
2009-12-11  5:23   ` [14/34] ext4: dont update the superblock in ext4_statfs() Greg KH
2009-12-11  5:23   ` [15/34] ext4: fix uninit block bitmap initialization when s_meta_first_bg is non-zero Greg KH
2009-12-11  5:23   ` [16/34] ext4: fix block validity checks so they work correctly with meta_bg Greg KH
2009-12-11  5:23   ` [17/34] ext4: avoid issuing unnecessary barriers Greg KH
2009-12-11  5:23   ` [18/34] ext4: fix error handling in ext4_ind_get_blocks() Greg KH
2009-12-11  5:23   ` [19/34] ext4: make trim/discard optional (and off by default) Greg KH
2009-12-11  5:23   ` [20/34] ext4: make "norecovery" an alias for "noload" Greg KH
2009-12-11  5:23   ` [21/34] ext4: Fix double-free of blocks with EXT4_IOC_MOVE_EXT Greg KH
2009-12-11  5:23   ` [22/34] ext4: initialize moved_len before calling ext4_move_extents() Greg KH
2009-12-11  5:23   ` [23/34] ext4: move_extent_per_page() cleanup Greg KH
2009-12-11  5:23   ` [24/34] jbd2: Add ENOMEM checking in and for jbd2_journal_write_metadata_buffer() Greg KH
2009-12-11  5:23   ` [25/34] ext4: Return the PTR_ERR of the correct pointer in setup_new_group_blocks() Greg KH
2009-12-11  5:23   ` [26/34] ext4: Avoid data / filesystem corruption when write fails to copy data Greg KH
2009-12-11  5:23   ` [27/34] ext4: wait for log to commit when umounting Greg KH
2009-12-11  5:23   ` [28/34] ext4: remove blocks from inode prealloc list on failure Greg KH
2009-12-11  5:23   ` [29/34] ext4: ext4_get_reserved_space() must return bytes instead of blocks Greg KH
2009-12-11  5:23   ` [30/34] ext4: quota macros cleanup Greg KH
2009-12-11  5:23   ` [31/34] ext4: fix incorrect block reservation on quota transfer Greg KH
2009-12-11  5:23   ` [32/34] ext4: Wait for proper transaction commit on fsync Greg KH
2009-12-11  5:23   ` [33/34] ext4: Fix insufficient checks in EXT4_IOC_MOVE_EXT Greg KH
2009-12-11  5:23   ` Greg KH [this message]

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