From 90ba983f6889e65a3b506b30dc606aa9d1d46cd2 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Mon, 11 Mar 2013 23:39:59 -0400 Subject: ext4: use atomic64_t for the per-flexbg free_clusters count A user who was using a 8TB+ file system and with a very large flexbg size (> 65536) could cause the atomic_t used in the struct flex_groups to overflow. This was detected by PaX security patchset: http://forums.grsecurity.net/viewtopic.php?f=3&t=3289&p=12551#p12551 This bug was introduced in commit 9f24e4208f7e, so it's been around since 2.6.30. :-( Fix this by using an atomic64_t for struct orlav_stats's free_clusters. Signed-off-by: "Theodore Ts'o" Reviewed-by: Lukas Czerner Cc: stable@vger.kernel.org --- fs/ext4/ext4.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'fs/ext4/ext4.h') diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 4a01ba31526..167ff564bbf 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -335,9 +335,9 @@ struct ext4_group_desc */ struct flex_groups { - atomic_t free_inodes; - atomic_t free_clusters; - atomic_t used_dirs; + atomic64_t free_clusters; + atomic_t free_inodes; + atomic_t used_dirs; }; #define EXT4_BG_INODE_UNINIT 0x0001 /* Inode table/bitmap not in use */ -- cgit v1.2.3 From 1ada47d9468fe3907f7f9e00179168f5e2f90803 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Wed, 20 Mar 2013 09:39:42 -0400 Subject: ext4: fix ext4_evict_inode() racing against workqueue processing code Commit 84c17543ab56 (ext4: move work from io_end to inode) triggered a regression when running xfstest #270 when the file system is mounted with dioread_nolock. The problem is that after ext4_evict_inode() calls ext4_ioend_wait(), this guarantees that last io_end structure has been freed, but it does not guarantee that the workqueue structure, which was moved into the inode by commit 84c17543ab56, is actually finished. Once ext4_flush_completed_IO() calls ext4_free_io_end() on CPU #1, this will allow ext4_ioend_wait() to return on CPU #2, at which point the evict_inode() codepath can race against the workqueue code on CPU #1 accessing EXT4_I(inode)->i_unwritten_work to find the next item of work to do. Fix this by calling cancel_work_sync() in ext4_ioend_wait(), which will be renamed ext4_ioend_shutdown(), since it is only used by ext4_evict_inode(). Also, move the call to ext4_ioend_shutdown() until after truncate_inode_pages() and filemap_write_and_wait() are called, to make sure all dirty pages have been written back and flushed from the page cache first. BUG: unable to handle kernel NULL pointer dereference at (null) IP: [] cwq_activate_delayed_work+0x3b/0x7e *pdpt = 0000000030bc3001 *pde = 0000000000000000 Oops: 0000 [#1] SMP DEBUG_PAGEALLOC Modules linked in: Pid: 6, comm: kworker/u:0 Not tainted 3.8.0-rc3-00013-g84c1754-dirty #91 Bochs Bochs EIP: 0060:[] EFLAGS: 00010046 CPU: 0 EIP is at cwq_activate_delayed_work+0x3b/0x7e EAX: 00000000 EBX: 00000000 ECX: f505fe54 EDX: 00000000 ESI: ed5b697c EDI: 00000006 EBP: f64b7e8c ESP: f64b7e84 DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 CR0: 8005003b CR2: 00000000 CR3: 30bc2000 CR4: 000006f0 DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 DR6: ffff0ff0 DR7: 00000400 Process kworker/u:0 (pid: 6, ti=f64b6000 task=f64b4160 task.ti=f64b6000) Stack: f505fe00 00000006 f64b7e9c c01de3d7 f6435540 00000003 f64b7efc c01def1d f6435540 00000002 00000000 0000008a c16d0808 c040a10b c16d07d8 c16d08b0 f505fe00 c16d0780 00000000 00000000 ee153df4 c1ce4a30 c17d0e30 00000000 Call Trace: [] cwq_dec_nr_in_flight+0x71/0xfb [] process_one_work+0x5d8/0x637 [] ? ext4_end_bio+0x300/0x300 [] worker_thread+0x249/0x3ef [] kthread+0xd8/0xeb [] ? manage_workers+0x4bb/0x4bb [] ? trace_hardirqs_on+0x27/0x37 [] ret_from_kernel_thread+0x1b/0x28 [] ? __init_kthread_worker+0x71/0x71 Code: 01 83 15 ac ff 6c c1 00 31 db 89 c6 8b 00 a8 04 74 12 89 c3 30 db 83 05 b0 ff 6c c1 01 83 15 b4 ff 6c c1 00 89 f0 e8 42 ff ff ff <8b> 13 89 f0 83 05 b8 ff 6c c1 6c c1 00 31 c9 83 EIP: [] cwq_activate_delayed_work+0x3b/0x7e SS:ESP 0068:f64b7e84 CR2: 0000000000000000 ---[ end trace a1923229da53d8a4 ]--- Signed-off-by: "Theodore Ts'o" Cc: Jan Kara --- fs/ext4/ext4.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/ext4/ext4.h') diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 167ff564bbf..3b83cd60479 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -2617,7 +2617,7 @@ extern int ext4_move_extents(struct file *o_filp, struct file *d_filp, extern int __init ext4_init_pageio(void); extern void ext4_add_complete_io(ext4_io_end_t *io_end); extern void ext4_exit_pageio(void); -extern void ext4_ioend_wait(struct inode *); +extern void ext4_ioend_shutdown(struct inode *); extern void ext4_free_io_end(ext4_io_end_t *io); extern ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags); extern void ext4_end_io_work(struct work_struct *work); -- cgit v1.2.3