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authorTheodore Ts'o <tytso@mit.edu>2012-08-17 08:54:52 -0400
committerBen Hutchings <ben@decadent.org.uk>2013-03-06 03:24:30 +0000
commit933ef2d5e70eba0cdd652a43157004e8619f66e9 (patch)
tree3f9f8506b3530f4f28e0c53033787a862cf0cde3
parente5a563d126bd68533e9afaf94ae5c1140921f859 (diff)
ext4: fix kernel BUG on large-scale rm -rf commands
commit 89a4e48f8479f8145eca9698f39fe188c982212f upstream. Commit 968dee7722: "ext4: fix hole punch failure when depth is greater than 0" introduced a regression in v3.5.1/v3.6-rc1 which caused kernel crashes when users ran run "rm -rf" on large directory hierarchy on ext4 filesystems on RAID devices: BUG: unable to handle kernel NULL pointer dereference at 0000000000000028 Process rm (pid: 18229, threadinfo ffff8801276bc000, task ffff880123631710) Call Trace: [<ffffffff81236483>] ? __ext4_handle_dirty_metadata+0x83/0x110 [<ffffffff812353d3>] ext4_ext_truncate+0x193/0x1d0 [<ffffffff8120a8cf>] ? ext4_mark_inode_dirty+0x7f/0x1f0 [<ffffffff81207e05>] ext4_truncate+0xf5/0x100 [<ffffffff8120cd51>] ext4_evict_inode+0x461/0x490 [<ffffffff811a1312>] evict+0xa2/0x1a0 [<ffffffff811a1513>] iput+0x103/0x1f0 [<ffffffff81196d84>] do_unlinkat+0x154/0x1c0 [<ffffffff8118cc3a>] ? sys_newfstatat+0x2a/0x40 [<ffffffff81197b0b>] sys_unlinkat+0x1b/0x50 [<ffffffff816135e9>] system_call_fastpath+0x16/0x1b Code: 8b 4d 20 0f b7 41 02 48 8d 04 40 48 8d 04 81 49 89 45 18 0f b7 49 02 48 83 c1 01 49 89 4d 00 e9 ae f8 ff ff 0f 1f 00 49 8b 45 28 <48> 8b 40 28 49 89 45 20 e9 85 f8 ff ff 0f 1f 80 00 00 00 RIP [<ffffffff81233164>] ext4_ext_remove_space+0xa34/0xdf0 This could be reproduced as follows: The problem in commit 968dee7722 was that caused the variable 'i' to be left uninitialized if the truncate required more space than was available in the journal. This resulted in the function ext4_ext_truncate_extend_restart() returning -EAGAIN, which caused ext4_ext_remove_space() to restart the truncate operation after starting a new jbd2 handle. Reported-by: Maciej ┼╗enczykowski <maze@google.com> Reported-by: Marti Raudsepp <marti@juffo.org> Tested-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
-rw-r--r--fs/ext4/extents.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 689f7337a021..b48e0dc2c22d 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -2614,6 +2614,7 @@ cont:
}
path[0].p_depth = depth;
path[0].p_hdr = ext_inode_hdr(inode);
+ i = 0;
if (ext4_ext_check(inode, path[0].p_hdr, depth)) {
err = -EIO;