This patch avoids that lockdep reports the following:
======================================================
WARNING: possible circular locking dependency detected
4.18.0-rc1 #62 Not tainted
------------------------------------------------------
kswapd0/84 is trying to acquire lock:
00000000c313516d (&xfs_nondir_ilock_class){++++}, at: xfs_free_eofblocks+0xa2/0x1e0
but task is already holding lock:
00000000591c83ae (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x5/0x30
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (fs_reclaim){+.+.}:
kmem_cache_alloc+0x2c/0x2b0
radix_tree_node_alloc.constprop.19+0x3d/0xc0
__radix_tree_create+0x161/0x1c0
__radix_tree_insert+0x45/0x210
dmz_map+0x245/0x2d0 [dm_zoned]
__map_bio+0x40/0x260
__split_and_process_non_flush+0x116/0x220
__split_and_process_bio+0x81/0x180
__dm_make_request.isra.32+0x5a/0x100
generic_make_request+0x36e/0x690
submit_bio+0x6c/0x140
mpage_readpages+0x19e/0x1f0
read_pages+0x6d/0x1b0
__do_page_cache_readahead+0x21b/0x2d0
force_page_cache_readahead+0xc4/0x100
generic_file_read_iter+0x7c6/0xd20
__vfs_read+0x102/0x180
vfs_read+0x9b/0x140
ksys_read+0x55/0xc0
do_syscall_64+0x5a/0x1f0
entry_SYSCALL_64_after_hwframe+0x49/0xbe
-> #1 (&dmz->chunk_lock){+.+.}:
dmz_map+0x133/0x2d0 [dm_zoned]
__map_bio+0x40/0x260
__split_and_process_non_flush+0x116/0x220
__split_and_process_bio+0x81/0x180
__dm_make_request.isra.32+0x5a/0x100
generic_make_request+0x36e/0x690
submit_bio+0x6c/0x140
_xfs_buf_ioapply+0x31c/0x590
xfs_buf_submit_wait+0x73/0x520
xfs_buf_read_map+0x134/0x2f0
xfs_trans_read_buf_map+0xc3/0x580
xfs_read_agf+0xa5/0x1e0
xfs_alloc_read_agf+0x59/0x2b0
xfs_alloc_pagf_init+0x27/0x60
xfs_bmap_longest_free_extent+0x43/0xb0
xfs_bmap_btalloc_nullfb+0x7f/0xf0
xfs_bmap_btalloc+0x428/0x7c0
xfs_bmapi_write+0x598/0xcc0
xfs_iomap_write_allocate+0x15a/0x330
xfs_map_blocks+0x1cf/0x3f0
xfs_do_writepage+0x15f/0x7b0
write_cache_pages+0x1ca/0x540
xfs_vm_writepages+0x65/0xa0
do_writepages+0x48/0xf0
__writeback_single_inode+0x58/0x730
writeback_sb_inodes+0x249/0x5c0
wb_writeback+0x11e/0x550
wb_workfn+0xa3/0x670
process_one_work+0x228/0x670
worker_thread+0x3c/0x390
kthread+0x11c/0x140
ret_from_fork+0x3a/0x50
-> #0 (&xfs_nondir_ilock_class){++++}:
down_read_nested+0x43/0x70
xfs_free_eofblocks+0xa2/0x1e0
xfs_fs_destroy_inode+0xac/0x270
dispose_list+0x51/0x80
prune_icache_sb+0x52/0x70
super_cache_scan+0x127/0x1a0
shrink_slab.part.47+0x1bd/0x590
shrink_node+0x3b5/0x470
balance_pgdat+0x158/0x3b0
kswapd+0x1ba/0x600
kthread+0x11c/0x140
ret_from_fork+0x3a/0x50
other info that might help us debug this:
Chain exists of:
&xfs_nondir_ilock_class --> &dmz->chunk_lock --> fs_reclaim
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(fs_reclaim);
lock(&dmz->chunk_lock);
lock(fs_reclaim);
lock(&xfs_nondir_ilock_class);
*** DEADLOCK ***
3 locks held by kswapd0/84:
#0: 00000000591c83ae (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x5/0x30
#1: 000000000f8208f5 (shrinker_rwsem){++++}, at: shrink_slab.part.47+0x3f/0x590
#2: 00000000cacefa54 (&type->s_umount_key#43){.+.+}, at: trylock_super+0x16/0x50
stack backtrace:
CPU: 7 PID: 84 Comm: kswapd0 Not tainted 4.18.0-rc1 #62
Hardware name: Supermicro Super Server/X10SRL-F, BIOS 2.0 12/17/2015
Call Trace:
dump_stack+0x85/0xcb
print_circular_bug.isra.36+0x1ce/0x1db
__lock_acquire+0x124e/0x1310
lock_acquire+0x9f/0x1f0
down_read_nested+0x43/0x70
xfs_free_eofblocks+0xa2/0x1e0
xfs_fs_destroy_inode+0xac/0x270
dispose_list+0x51/0x80
prune_icache_sb+0x52/0x70
super_cache_scan+0x127/0x1a0
shrink_slab.part.47+0x1bd/0x590
shrink_node+0x3b5/0x470
balance_pgdat+0x158/0x3b0
kswapd+0x1ba/0x600
kthread+0x11c/0x140
ret_from_fork+0x3a/0x50
Reported-by: Masato Suzuki <masato.suzuki@xxxxxxx>
Fixes: 4218a9554653 ("dm zoned: use GFP_NOIO in I/O path")
Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxx>
Cc: Damien Le Moal <Damien.LeMoal@xxxxxxx>
Cc: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
---
Changes compared to v1: added "Cc: stable"
drivers/md/dm-zoned-target.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/md/dm-zoned-target.c b/drivers/md/dm-zoned-target.c
index 3c0e45f4dcf5..a44183ff4be0 100644
--- a/drivers/md/dm-zoned-target.c
+++ b/drivers/md/dm-zoned-target.c
@@ -787,7 +787,7 @@ static int dmz_ctr(struct dm_target *ti, unsigned int argc, char **argv)
/* Chunk BIO work */
mutex_init(&dmz->chunk_lock);
- INIT_RADIX_TREE(&dmz->chunk_rxtree, GFP_KERNEL);
+ INIT_RADIX_TREE(&dmz->chunk_rxtree, GFP_NOIO);
dmz->chunk_wq = alloc_workqueue("dmz_cwq_%s", WQ_MEM_RECLAIM | WQ_UNBOUND,
0, dev->name);
if (!dmz->chunk_wq) {
--
2.17.1
--
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