[PATCH] jfs: lockdep fix

From: Krzysztof Helt
Date: Tue Oct 20 2009 - 14:48:24 EST

From: Krzysztof Helt <krzysztof.h1@xxxxx>

Release rdwrlock semaphore during memory allocation.
This fixes the locked already reported here:

http://www.mail-archive.com/jfs-discussion@xxxxxxxxxxxxxxxxxxxxx/msg01389.html

The problem here is that memory allocation is done with rdwrlock
semaphore taken and the VM can get into the jfs layer taking the
rdwrlock again.

Also, the patch fixes the lockdep below. This problem is created because
the rdwrlock semaphore acquires the commit_mutex and it is called with
interrupts enabled. The interrupt may hit with the commit_mutex taken
and take the rdwrlock (again) inside the interrupt context.

=========================================================
[ INFO: possible irq lock inversion dependency detected ]
2.6.32-rc3 #99
---------------------------------------------------------
kswapd0/180 just changed the state of lock:
(&jfs_ip->rdwrlock#2){++++-.}, at: [<c02e2207>] jfs_get_block+0x47/0x280
but this lock took another, RECLAIM_FS-unsafe lock in the past:
(&jfs_ip->commit_mutex){+.+.+.}

and interrupts could create inverse lock ordering between them.


other info that might help us debug this:
no locks held by kswapd0/180.

the shortest dependencies between 2nd lock and 1st lock:
-> (&jfs_ip->commit_mutex){+.+.+.} ops: 7937 {
HARDIRQ-ON-W at:
[<c0246dc6>] __lock_acquire+0x5d6/0xab0
[<c024731a>] lock_acquire+0x7a/0xa0
[<c044c125>] mutex_lock_nested+0x55/0x280
[<c02e1d11>] jfs_commit_inode+0x61/0x120
[<c02e2075>] jfs_write_inode+0x35/0x50
[<c029c2da>] writeback_single_inode+0x1ba/0x250
[<c029ca3d>] writeback_inodes_wb+0x27d/0x3b0
[<c029cc5c>] wb_writeback+0xec/0x180
[<c029cf37>] wb_do_writeback+0x1a7/0x1d0
[<c029cf92>] bdi_writeback_task+0x32/0xa0
[<c026b16d>] bdi_start_fn+0x5d/0xb0
[<c0234e5c>] kthread+0x6c/0x80
[<c0203477>] kernel_thread_helper+0x7/0x10
SOFTIRQ-ON-W at:
[<c0246ded>] __lock_acquire+0x5fd/0xab0
[<c024731a>] lock_acquire+0x7a/0xa0
[<c044c125>] mutex_lock_nested+0x55/0x280
[<c02e1d11>] jfs_commit_inode+0x61/0x120
[<c02e2075>] jfs_write_inode+0x35/0x50
[<c029c2da>] writeback_single_inode+0x1ba/0x250
[<c029ca3d>] writeback_inodes_wb+0x27d/0x3b0
[<c029cc5c>] wb_writeback+0xec/0x180
[<c029cf37>] wb_do_writeback+0x1a7/0x1d0
[<c029cf92>] bdi_writeback_task+0x32/0xa0
[<c026b16d>] bdi_start_fn+0x5d/0xb0
[<c0234e5c>] kthread+0x6c/0x80
[<c0203477>] kernel_thread_helper+0x7/0x10
RECLAIM_FS-ON-W at:
[<c02444f5>] mark_held_locks+0x55/0x70
[<c0244b42>] lockdep_trace_alloc+0xa2/0xd0
[<c027ed78>] kmem_cache_alloc+0x28/0x100
[<c032090b>] radix_tree_preload+0x1b/0x60
[<c025b2d1>] add_to_page_cache_locked+0x21/0xe0
[<c025b3b8>] add_to_page_cache_lru+0x28/0x70
[<c025b55a>] read_cache_page_async+0xaa/0x140
[<c025b602>] read_cache_page+0x12/0x60
[<c02fac29>] __get_metapage+0x109/0x3f0
[<c02ecb3d>] diWrite+0x16d/0x580
[<c02fe295>] txCommit+0x1b5/0x1040
[<c02e3fea>] jfs_create+0x26a/0x330
[<c028a91f>] vfs_create+0x7f/0xd0
[<c028d4a1>] do_filp_open+0x6c1/0x7e0
[<c0280711>] do_sys_open+0x51/0x120
[<c0280849>] sys_open+0x29/0x40
[<c0202c45>] syscall_call+0x7/0xb
INITIAL USE at:
[<c0246a02>] __lock_acquire+0x212/0xab0
[<c024731a>] lock_acquire+0x7a/0xa0
[<c044c125>] mutex_lock_nested+0x55/0x280
[<c02e1d11>] jfs_commit_inode+0x61/0x120
[<c02e2075>] jfs_write_inode+0x35/0x50
[<c029c2da>] writeback_single_inode+0x1ba/0x250
[<c029ca3d>] writeback_inodes_wb+0x27d/0x3b0
[<c029cc5c>] wb_writeback+0xec/0x180
[<c029cf37>] wb_do_writeback+0x1a7/0x1d0
[<c029cf92>] bdi_writeback_task+0x32/0xa0
[<c026b16d>] bdi_start_fn+0x5d/0xb0
[<c0234e5c>] kthread+0x6c/0x80
[<c0203477>] kernel_thread_helper+0x7/0x10
}
... key at: [<c0a9523c>] __key.25521+0x0/0x8
... acquired at:
[<c02461d5>] validate_chain+0xa25/0x1040
[<c0246aca>] __lock_acquire+0x2da/0xab0
[<c024731a>] lock_acquire+0x7a/0xa0
[<c044c125>] mutex_lock_nested+0x55/0x280
[<c02f98f9>] extAlloc+0x49/0x5c0
[<c02e23e7>] jfs_get_block+0x227/0x280
[<c02a45c0>] nobh_write_begin+0x130/0x3e0
[<c02e1c2d>] jfs_write_begin+0x3d/0x50
[<c025b9de>] generic_file_buffered_write+0xde/0x260
[<c025bf44>] __generic_file_aio_write+0x244/0x490
[<c025c1e8>] generic_file_aio_write+0x58/0xc0
[<c0281f6c>] do_sync_write+0xcc/0x110
[<c02827b6>] vfs_write+0x96/0x160
[<c0282c9d>] sys_write+0x3d/0x70
[<c0202c45>] syscall_call+0x7/0xb

-> (&jfs_ip->rdwrlock#2){++++-.} ops: 9669 {
HARDIRQ-ON-W at:
[<c0246dc6>] __lock_acquire+0x5d6/0xab0
[<c024731a>] lock_acquire+0x7a/0xa0
[<c0238ab0>] down_write_nested+0x50/0x70
[<c02e2207>] jfs_get_block+0x47/0x280
[<c02a45c0>] nobh_write_begin+0x130/0x3e0
[<c02e1c2d>] jfs_write_begin+0x3d/0x50
[<c025b9de>] generic_file_buffered_write+0xde/0x260
[<c025bf44>] __generic_file_aio_write+0x244/0x490
[<c025c1e8>] generic_file_aio_write+0x58/0xc0
[<c0281f6c>] do_sync_write+0xcc/0x110
[<c02827b6>] vfs_write+0x96/0x160
[<c0282c9d>] sys_write+0x3d/0x70
[<c0202c45>] syscall_call+0x7/0xb
HARDIRQ-ON-R at:
[<c02469cf>] __lock_acquire+0x1df/0xab0
[<c024731a>] lock_acquire+0x7a/0xa0
[<c0238c10>] down_read_nested+0x50/0x70
[<c02e22a6>] jfs_get_block+0xe6/0x280
[<c02a9c56>] do_mpage_readpage+0x3a6/0x510
[<c02a9ebd>] mpage_readpages+0x9d/0xd0
[<c02e1c59>] jfs_readpages+0x19/0x20
[<c0262433>] __do_page_cache_readahead+0x163/0x1f0
[<c02624e8>] ra_submit+0x28/0x40
[<c026270b>] ondemand_readahead+0x12b/0x220
[<c02628a8>] page_cache_sync_readahead+0x28/0x30
[<c025c8fa>] generic_file_aio_read+0x4ca/0x640
[<c028207c>] do_sync_read+0xcc/0x110
[<c0282914>] vfs_read+0x94/0x150
[<c0282c2d>] sys_read+0x3d/0x70
[<c0202c45>] syscall_call+0x7/0xb
SOFTIRQ-ON-W at:
[<c0246ded>] __lock_acquire+0x5fd/0xab0
[<c024731a>] lock_acquire+0x7a/0xa0
[<c0238ab0>] down_write_nested+0x50/0x70
[<c02e2207>] jfs_get_block+0x47/0x280
[<c02a45c0>] nobh_write_begin+0x130/0x3e0
[<c02e1c2d>] jfs_write_begin+0x3d/0x50
[<c025b9de>] generic_file_buffered_write+0xde/0x260
[<c025bf44>] __generic_file_aio_write+0x244/0x490
[<c025c1e8>] generic_file_aio_write+0x58/0xc0
[<c0281f6c>] do_sync_write+0xcc/0x110
[<c02827b6>] vfs_write+0x96/0x160
[<c0282c9d>] sys_write+0x3d/0x70
[<c0202c45>] syscall_call+0x7/0xb
SOFTIRQ-ON-R at:
[<c0246efe>] __lock_acquire+0x70e/0xab0
[<c024731a>] lock_acquire+0x7a/0xa0
[<c0238c10>] down_read_nested+0x50/0x70
[<c02e22a6>] jfs_get_block+0xe6/0x280
[<c02a9c56>] do_mpage_readpage+0x3a6/0x510
[<c02a9ebd>] mpage_readpages+0x9d/0xd0
[<c02e1c59>] jfs_readpages+0x19/0x20
[<c0262433>] __do_page_cache_readahead+0x163/0x1f0
[<c02624e8>] ra_submit+0x28/0x40
[<c026270b>] ondemand_readahead+0x12b/0x220
[<c02628a8>] page_cache_sync_readahead+0x28/0x30
[<c025c8fa>] generic_file_aio_read+0x4ca/0x640
[<c028207c>] do_sync_read+0xcc/0x110
[<c0282914>] vfs_read+0x94/0x150
[<c0282c2d>] sys_read+0x3d/0x70
[<c0202c45>] syscall_call+0x7/0xb
IN-RECLAIM_FS-W at:
[<c0246ec7>] __lock_acquire+0x6d7/0xab0
[<c024731a>] lock_acquire+0x7a/0xa0
[<c0238ab0>] down_write_nested+0x50/0x70
[<c02e2207>] jfs_get_block+0x47/0x280
[<c02a30b3>] __block_write_full_page+0xe3/0x320
[<c02a33b7>] block_write_full_page_endio+0xc7/0xe0
[<c02a33e2>] block_write_full_page+0x12/0x20
[<c02e1c9f>] jfs_writepage+0xf/0x20
[<c0264f0c>] shrink_page_list+0x31c/0x6c0
[<c0265539>] shrink_list+0x289/0x630
[<c0265b57>] shrink_zone+0x277/0x2f0
[<c026649b>] kswapd+0x48b/0x4f0
[<c0234e5c>] kthread+0x6c/0x80
[<c0203477>] kernel_thread_helper+0x7/0x10
INITIAL USE at:
[<c0246a02>] __lock_acquire+0x212/0xab0
[<c024731a>] lock_acquire+0x7a/0xa0
[<c0238c10>] down_read_nested+0x50/0x70
[<c02e22a6>] jfs_get_block+0xe6/0x280
[<c02a9c56>] do_mpage_readpage+0x3a6/0x510
[<c02a9ebd>] mpage_readpages+0x9d/0xd0
[<c02e1c59>] jfs_readpages+0x19/0x20
[<c0262433>] __do_page_cache_readahead+0x163/0x1f0
[<c02624e8>] ra_submit+0x28/0x40
[<c026270b>] ondemand_readahead+0x12b/0x220
[<c02628a8>] page_cache_sync_readahead+0x28/0x30
[<c025c8fa>] generic_file_aio_read+0x4ca/0x640
[<c028207c>] do_sync_read+0xcc/0x110
[<c0282914>] vfs_read+0x94/0x150
[<c0282c2d>] sys_read+0x3d/0x70
[<c0202c45>] syscall_call+0x7/0xb
}
... key at: [<c0a95244>] __key.25520+0x0/0x1c
... acquired at:
[<c0247f3c>] check_usage_forwards+0x7c/0xd0
[<c024406d>] mark_lock+0x17d/0x5b0
[<c0246ec7>] __lock_acquire+0x6d7/0xab0
[<c024731a>] lock_acquire+0x7a/0xa0
[<c0238ab0>] down_write_nested+0x50/0x70
[<c02e2207>] jfs_get_block+0x47/0x280
[<c02a30b3>] __block_write_full_page+0xe3/0x320
[<c02a33b7>] block_write_full_page_endio+0xc7/0xe0
[<c02a33e2>] block_write_full_page+0x12/0x20
[<c02e1c9f>] jfs_writepage+0xf/0x20
[<c0264f0c>] shrink_page_list+0x31c/0x6c0
[<c0265539>] shrink_list+0x289/0x630
[<c0265b57>] shrink_zone+0x277/0x2f0
[<c026649b>] kswapd+0x48b/0x4f0
[<c0234e5c>] kthread+0x6c/0x80
[<c0203477>] kernel_thread_helper+0x7/0x10


stack backtrace:
Pid: 180, comm: kswapd0 Not tainted 2.6.32-rc3 #99
Call Trace:
[<c0243d18>] print_irq_inversion_bug+0x108/0x130
[<c0247f3c>] check_usage_forwards+0x7c/0xd0
[<c024406d>] mark_lock+0x17d/0x5b0
[<c0247ec0>] ? check_usage_forwards+0x0/0xd0
[<c0246ec7>] __lock_acquire+0x6d7/0xab0
[<c024731a>] lock_acquire+0x7a/0xa0
[<c02e2207>] ? jfs_get_block+0x47/0x280
[<c0238ab0>] down_write_nested+0x50/0x70
[<c02e2207>] ? jfs_get_block+0x47/0x280
[<c02e2207>] jfs_get_block+0x47/0x280
[<c044d7dd>] ? _spin_unlock+0x1d/0x20
[<c02a17c7>] ? create_empty_buffers+0x77/0x90
[<c02a30b3>] __block_write_full_page+0xe3/0x320
[<c02e21c0>] ? jfs_get_block+0x0/0x280
[<c02a33b7>] block_write_full_page_endio+0xc7/0xe0
[<c02a3f50>] ? end_buffer_async_write+0x0/0x160
[<c02e21c0>] ? jfs_get_block+0x0/0x280
[<c024463c>] ? trace_hardirqs_on_caller+0x12c/0x180
[<c02a33e2>] block_write_full_page+0x12/0x20
[<c02a3f50>] ? end_buffer_async_write+0x0/0x160
[<c02e1c9f>] jfs_writepage+0xf/0x20
[<c0264f0c>] shrink_page_list+0x31c/0x6c0
[<c0265539>] shrink_list+0x289/0x630
[<c0265b57>] shrink_zone+0x277/0x2f0
[<c026649b>] kswapd+0x48b/0x4f0
[<c0264170>] ? isolate_pages_global+0x0/0x1f0
[<c0234f30>] ? autoremove_wake_function+0x0/0x40
[<c0266010>] ? kswapd+0x0/0x4f0
[<c0234e5c>] kthread+0x6c/0x80
[<c0234df0>] ? kthread+0x0/0x80
[<c0203477>] kernel_thread_helper+0x7/0x10

Signed-off-by: Krzysztof Helt <krzysztof.h1@xxxxx>

---

I am not sure if this is the right fix to the problem. The heavy use of
the jfs volume can lock up a machine (e.g. hit me in Ubuntu 9.04).

diff --git a/fs/jfs/inode.c b/fs/jfs/inode.c
index b2ae190..de18324 100644
--- a/fs/jfs/inode.c
+++ b/fs/jfs/inode.c
@@ -244,9 +244,22 @@ int jfs_get_block(struct inode *ip, sector_t lblock,
#ifdef _JFS_4K
if ((rc = extHint(ip, lblock64 << ip->i_sb->s_blocksize_bits, &xad)))
goto unlock;
+
+ /* release lock to avoid lockdep with jfs_ip->commit_mutex */
+ if (create)
+ IWRITE_UNLOCK(ip);
+ else
+ IREAD_UNLOCK(ip);
+
rc = extAlloc(ip, xlen, lblock64, &xad, false);
+
if (rc)
- goto unlock;
+ return rc;
+
+ if (create)
+ IWRITE_LOCK(ip, RDWRLOCK_NORMAL);
+ else
+ IREAD_LOCK(ip, RDWRLOCK_NORMAL);

set_buffer_new(bh_result);
map_bh(bh_result, ip->i_sb, addressXAD(&xad));

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