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authorDmitry Monakhov <dmonakhov@openvz.org>2013-04-03 22:08:52 -0400
committerTheodore Ts'o <tytso@mit.edu>2013-04-03 22:08:52 -0400
commit5d3ee20855e28169d711b394857ee608a5023094 (patch)
tree37d2ec24f6e5019a05aa1a741b9c45130987b0c0 /fs/ext4/ext4_jbd2.h
parent794446c6946513c684d448205fbd76fa35f38b72 (diff)
ext4: fix journal callback list traversal
It is incorrect to use list_for_each_entry_safe() for journal callback traversial because ->next may be removed by other task: ->ext4_mb_free_metadata() ->ext4_mb_free_metadata() ->ext4_journal_callback_del() This results in the following issue: WARNING: at lib/list_debug.c:62 __list_del_entry+0x1c0/0x250() Hardware name: list_del corruption. prev->next should be ffff88019a4ec198, but was 6b6b6b6b6b6b6b6b Modules linked in: cpufreq_ondemand acpi_cpufreq freq_table mperf coretemp kvm_intel kvm crc32c_intel ghash_clmulni_intel microcode sg xhci_hcd button sd_mod crc_t10dif aesni_intel ablk_helper cryptd lrw aes_x86_64 xts gf128mul ahci libahci pata_acpi ata_generic dm_mirror dm_region_hash dm_log dm_mod Pid: 16400, comm: jbd2/dm-1-8 Tainted: G W 3.8.0-rc3+ #107 Call Trace: [<ffffffff8106fb0d>] warn_slowpath_common+0xad/0xf0 [<ffffffff8106fc06>] warn_slowpath_fmt+0x46/0x50 [<ffffffff813637e9>] ? ext4_journal_commit_callback+0x99/0xc0 [<ffffffff8148cae0>] __list_del_entry+0x1c0/0x250 [<ffffffff813637bf>] ext4_journal_commit_callback+0x6f/0xc0 [<ffffffff813ca336>] jbd2_journal_commit_transaction+0x23a6/0x2570 [<ffffffff8108aa42>] ? try_to_del_timer_sync+0x82/0xa0 [<ffffffff8108b491>] ? del_timer_sync+0x91/0x1e0 [<ffffffff813d3ecf>] kjournald2+0x19f/0x6a0 [<ffffffff810ad630>] ? wake_up_bit+0x40/0x40 [<ffffffff813d3d30>] ? bit_spin_lock+0x80/0x80 [<ffffffff810ac6be>] kthread+0x10e/0x120 [<ffffffff810ac5b0>] ? __init_kthread_worker+0x70/0x70 [<ffffffff818ff6ac>] ret_from_fork+0x7c/0xb0 [<ffffffff810ac5b0>] ? __init_kthread_worker+0x70/0x70 This patch fix the issue as follows: - ext4_journal_commit_callback() make list truly traversial safe simply by always starting from list_head - fix race between two ext4_journal_callback_del() and ext4_journal_callback_try_del() Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Jan Kara <jack@suse.cz> Cc: stable@vger.kernel.com
Diffstat (limited to 'fs/ext4/ext4_jbd2.h')
-rw-r--r--fs/ext4/ext4_jbd2.h6
1 files changed, 5 insertions, 1 deletions
diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h
index 4c216b1bf20c..aeed0bac693b 100644
--- a/fs/ext4/ext4_jbd2.h
+++ b/fs/ext4/ext4_jbd2.h
@@ -194,16 +194,20 @@ static inline void ext4_journal_callback_add(handle_t *handle,
* ext4_journal_callback_del: delete a registered callback
* @handle: active journal transaction handle on which callback was registered
* @jce: registered journal callback entry to unregister
+ * Return true if object was sucessfully removed
*/
-static inline void ext4_journal_callback_del(handle_t *handle,
+static inline bool ext4_journal_callback_try_del(handle_t *handle,
struct ext4_journal_cb_entry *jce)
{
+ bool deleted;
struct ext4_sb_info *sbi =
EXT4_SB(handle->h_transaction->t_journal->j_private);
spin_lock(&sbi->s_md_lock);
+ deleted = !list_empty(&jce->jce_list);
list_del_init(&jce->jce_list);
spin_unlock(&sbi->s_md_lock);
+ return deleted;
}
int