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| author | Dmitry Monakhov <dmonakhov@openvz.org> | 2013-04-04 06:08:52 +0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2013-04-04 06:08:52 +0400 |
| commit | 5d3ee20855e28169d711b394857ee608a5023094 (patch) | |
| tree | 37d2ec24f6e5019a05aa1a741b9c45130987b0c0 /fs/ext4/mballoc.c | |
| parent | 794446c6946513c684d448205fbd76fa35f38b72 (diff) | |
| download | linux-5d3ee20855e28169d711b394857ee608a5023094.tar.xz | |
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/mballoc.c')
| -rw-r--r-- | fs/ext4/mballoc.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 36c82a39d03f..580aada3d1bb 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -4423,11 +4423,11 @@ ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b, node = rb_prev(new_node); if (node) { entry = rb_entry(node, struct ext4_free_data, efd_node); - if (can_merge(entry, new_entry)) { + if (can_merge(entry, new_entry) && + ext4_journal_callback_try_del(handle, &entry->efd_jce)) { new_entry->efd_start_cluster = entry->efd_start_cluster; new_entry->efd_count += entry->efd_count; rb_erase(node, &(db->bb_free_root)); - ext4_journal_callback_del(handle, &entry->efd_jce); kmem_cache_free(ext4_free_data_cachep, entry); } } @@ -4435,10 +4435,10 @@ ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b, node = rb_next(new_node); if (node) { entry = rb_entry(node, struct ext4_free_data, efd_node); - if (can_merge(new_entry, entry)) { + if (can_merge(new_entry, entry) && + ext4_journal_callback_try_del(handle, &entry->efd_jce)) { new_entry->efd_count += entry->efd_count; rb_erase(node, &(db->bb_free_root)); - ext4_journal_callback_del(handle, &entry->efd_jce); kmem_cache_free(ext4_free_data_cachep, entry); } } |