linux/fs/btrfs
Josef Bacik 11a19a9087 btrfs: allocate new inode in NOFS context
A user reported a lockdep splat

 ======================================================
 WARNING: possible circular locking dependency detected
 5.2.11-gentoo #2 Not tainted
 ------------------------------------------------------
 kswapd0/711 is trying to acquire lock:
 000000007777a663 (sb_internal){.+.+}, at: start_transaction+0x3a8/0x500

but task is already holding lock:
 000000000ba86300 (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x0/0x30

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (fs_reclaim){+.+.}:
 kmem_cache_alloc+0x1f/0x1c0
 btrfs_alloc_inode+0x1f/0x260
 alloc_inode+0x16/0xa0
 new_inode+0xe/0xb0
 btrfs_new_inode+0x70/0x610
 btrfs_symlink+0xd0/0x420
 vfs_symlink+0x9c/0x100
 do_symlinkat+0x66/0xe0
 do_syscall_64+0x55/0x1c0
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #0 (sb_internal){.+.+}:
 __sb_start_write+0xf6/0x150
 start_transaction+0x3a8/0x500
 btrfs_commit_inode_delayed_inode+0x59/0x110
 btrfs_evict_inode+0x19e/0x4c0
 evict+0xbc/0x1f0
 inode_lru_isolate+0x113/0x190
 __list_lru_walk_one.isra.4+0x5c/0x100
 list_lru_walk_one+0x32/0x50
 prune_icache_sb+0x36/0x80
 super_cache_scan+0x14a/0x1d0
 do_shrink_slab+0x131/0x320
 shrink_node+0xf7/0x380
 balance_pgdat+0x2d5/0x640
 kswapd+0x2ba/0x5e0
 kthread+0x147/0x160
 ret_from_fork+0x24/0x30

other info that might help us debug this:

 Possible unsafe locking scenario:

 CPU0 CPU1
 ---- ----
 lock(fs_reclaim);
 lock(sb_internal);
 lock(fs_reclaim);
 lock(sb_internal);
*** DEADLOCK ***

 3 locks held by kswapd0/711:
 #0: 000000000ba86300 (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x0/0x30
 #1: 000000004a5100f8 (shrinker_rwsem){++++}, at: shrink_node+0x9a/0x380
 #2: 00000000f956fa46 (&type->s_umount_key#30){++++}, at: super_cache_scan+0x35/0x1d0

stack backtrace:
 CPU: 7 PID: 711 Comm: kswapd0 Not tainted 5.2.11-gentoo #2
 Hardware name: Dell Inc. Precision Tower 3620/0MWYPT, BIOS 2.4.2 09/29/2017
 Call Trace:
 dump_stack+0x85/0xc7
 print_circular_bug.cold.40+0x1d9/0x235
 __lock_acquire+0x18b1/0x1f00
 lock_acquire+0xa6/0x170
 ? start_transaction+0x3a8/0x500
 __sb_start_write+0xf6/0x150
 ? start_transaction+0x3a8/0x500
 start_transaction+0x3a8/0x500
 btrfs_commit_inode_delayed_inode+0x59/0x110
 btrfs_evict_inode+0x19e/0x4c0
 ? var_wake_function+0x20/0x20
 evict+0xbc/0x1f0
 inode_lru_isolate+0x113/0x190
 ? discard_new_inode+0xc0/0xc0
 __list_lru_walk_one.isra.4+0x5c/0x100
 ? discard_new_inode+0xc0/0xc0
 list_lru_walk_one+0x32/0x50
 prune_icache_sb+0x36/0x80
 super_cache_scan+0x14a/0x1d0
 do_shrink_slab+0x131/0x320
 shrink_node+0xf7/0x380
 balance_pgdat+0x2d5/0x640
 kswapd+0x2ba/0x5e0
 ? __wake_up_common_lock+0x90/0x90
 kthread+0x147/0x160
 ? balance_pgdat+0x640/0x640
 ? __kthread_create_on_node+0x160/0x160
 ret_from_fork+0x24/0x30

This is because btrfs_new_inode() calls new_inode() under the
transaction.  We could probably move the new_inode() outside of this but
for now just wrap it in memalloc_nofs_save().

Reported-by: Zdenek Sojka <zsojka@seznam.cz>
Fixes: 712e36c5f2 ("btrfs: use GFP_KERNEL in btrfs_alloc_inode")
CC: stable@vger.kernel.org # 4.16+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-10-01 20:12:27 +02:00
..
tests Btrfs: fix selftests failure due to uninitialized i_mode in test inodes 2019-09-24 14:45:02 +02:00
acl.c btrfs: cleanup btrfs_setxattr_trans and drop transaction parameter 2019-04-29 19:02:44 +02:00
async-thread.c btrfs: async-thread: convert defines to enums 2019-09-09 14:59:03 +02:00
async-thread.h btrfs: replace GPL boilerplate by SPDX -- headers 2018-04-12 16:29:46 +02:00
backref.c Btrfs: fix deadlock between fiemap and transaction commits 2019-07-30 18:25:12 +02:00
backref.h btrfs: fiemap: preallocate ulists for btrfs_check_shared 2019-07-01 13:34:53 +02:00
block-group.c btrfs: add space reservation tracepoint for reserved bytes 2019-09-09 14:59:17 +02:00
block-group.h btrfs: move struct io_ctl to free-space-cache.h 2019-09-09 14:59:15 +02:00
block-rsv.c btrfs: use btrfs_try_granting_tickets in update_global_rsv 2019-09-09 14:59:19 +02:00
block-rsv.h btrfs: migrate the global_block_rsv helpers to block-rsv.c 2019-07-02 12:30:55 +02:00
btrfs_inode.h btrfs: remove assumption about csum type form btrfs_print_data_csum_error() 2019-07-01 13:35:02 +02:00
check-integrity.c btrfs: reduce stack usage for btrfsic_process_written_block 2019-09-09 14:58:58 +02:00
check-integrity.h btrfs: replace GPL boilerplate by SPDX -- headers 2018-04-12 16:29:46 +02:00
compression.c btrfs: move cond_wake_up functions out of ctree 2019-09-09 14:59:15 +02:00
compression.h btrfs: compression: replace set_level callbacks by a common helper 2019-09-09 14:59:11 +02:00
ctree.c btrfs: Don't assign retval of btrfs_try_tree_write_lock/btrfs_tree_read_lock_atomic 2019-09-09 14:59:20 +02:00
ctree.h btrfs: create structure to encode checksum type and length 2019-09-09 14:59:19 +02:00
delalloc-space.c btrfs: roll tracepoint into btrfs_space_info_update helper 2019-09-09 14:59:17 +02:00
delalloc-space.h btrfs: migrate the delalloc space stuff to it's own home 2019-07-04 17:26:17 +02:00
delayed-inode.c btrfs: move cond_wake_up functions out of ctree 2019-09-09 14:59:15 +02:00
delayed-inode.h Btrfs: delayed-inode: use rb_first_cached for ins_root and del_root 2018-10-15 17:23:33 +02:00
delayed-ref.c btrfs: rename btrfs_space_info_add_old_bytes 2019-09-09 14:59:18 +02:00
delayed-ref.h btrfs: migrate the delayed refs rsv code 2019-07-04 17:26:17 +02:00
dev-replace.c btrfs: move cond_wake_up functions out of ctree 2019-09-09 14:59:15 +02:00
dev-replace.h btrfs: get fs_info from trans in btrfs_run_dev_replace 2019-04-29 19:02:43 +02:00
dir-item.c btrfs: remove unused parameter fs_info from btrfs_extend_item 2019-04-29 19:02:50 +02:00
disk-io.c btrfs: Detect unbalanced tree with empty leaf before crashing btree operations 2019-09-09 14:59:14 +02:00
disk-io.h btrfs: Make reada_tree_block_flagged private 2019-09-09 14:59:11 +02:00
export.c btrfs: Remove 'objectid' member from struct btrfs_root 2018-10-15 17:23:25 +02:00
export.h btrfs: replace GPL boilerplate by SPDX -- headers 2018-04-12 16:29:46 +02:00
extent_io.c Btrfs: fix missing error return if writeback for extent buffer never started 2019-09-24 14:45:23 +02:00
extent_io.h btrfs: Remove delalloc_end argument from extent_clear_unlock_delalloc 2019-09-09 14:58:59 +02:00
extent_map.c btrfs: assert extent map tree lock in add_extent_mapping 2019-09-09 14:59:00 +02:00
extent_map.h btrfs: Remove impossible condition from mergable_maps 2019-02-25 14:13:21 +01:00
extent-tree.c btrfs: refactor the ticket wakeup code 2019-09-09 14:59:18 +02:00
file-item.c btrfs: directly call into crypto framework for checksumming 2019-07-01 13:35:02 +02:00
file.c Btrfs: fix memory leak due to concurrent append writes with fiemap 2019-10-01 18:40:58 +02:00
free-space-cache.c btrfs: stop clearing EXTENT_DIRTY in inode I/O tree 2019-09-09 14:59:17 +02:00
free-space-cache.h btrfs: move struct io_ctl to free-space-cache.h 2019-09-09 14:59:15 +02:00
free-space-tree.c btrfs: move basic block_group definitions to their own header 2019-09-09 14:59:03 +02:00
free-space-tree.h btrfs: move basic block_group definitions to their own header 2019-09-09 14:59:03 +02:00
inode-item.c btrfs: Make btrfs_find_name_in_ext_backref return struct btrfs_inode_extref 2019-09-09 14:59:16 +02:00
inode-map.c btrfs: rename the btrfs_calc_*_metadata_size helpers 2019-09-09 14:59:13 +02:00
inode-map.h btrfs: replace GPL boilerplate by SPDX -- headers 2018-04-12 16:29:46 +02:00
inode.c btrfs: allocate new inode in NOFS context 2019-10-01 20:12:27 +02:00
ioctl.c btrfs: stop clearing EXTENT_DIRTY in inode I/O tree 2019-09-09 14:59:17 +02:00
Kconfig btrfs: Fix build error while LIBCRC32C is module 2019-07-17 17:03:30 +02:00
locking.c btrfs: move cond_wake_up functions out of ctree 2019-09-09 14:59:15 +02:00
locking.h btrfs: Remove unused locking functions 2019-09-09 14:58:59 +02:00
lzo.c btrfs: compression: replace set_level callbacks by a common helper 2019-09-09 14:59:11 +02:00
Makefile btrfs: migrate the block group lookup code 2019-09-09 14:59:04 +02:00
misc.h btrfs: move math functions to misc.h 2019-09-09 14:59:15 +02:00
ordered-data.c btrfs: move cond_wake_up functions out of ctree 2019-09-09 14:59:15 +02:00
ordered-data.h btrfs: don't assume ordered sums to be 4 bytes 2019-07-01 13:35:00 +02:00
orphan.c btrfs: replace GPL boilerplate by SPDX -- sources 2018-04-12 16:29:51 +02:00
print-tree.c btrfs: switch extent_buffer write_locks from atomic to int 2019-07-02 12:30:47 +02:00
print-tree.h btrfs: print-tree: debugging output enhancement 2018-04-20 19:18:16 +02:00
props.c btrfs: rename the btrfs_calc_*_metadata_size helpers 2019-09-09 14:59:13 +02:00
props.h btrfs: delete unused function btrfs_set_prop_trans 2019-04-29 19:02:54 +02:00
qgroup.c btrfs: qgroup: Fix reserved data space leak if we have multiple reserve calls 2019-09-27 15:24:34 +02:00
qgroup.h btrfs: qgroup: Move reserved data accounting from btrfs_delayed_ref_head to btrfs_qgroup_extent_record 2019-02-25 14:13:39 +01:00
raid56.c btrfs: move private raid56 definitions from ctree.h 2019-09-09 14:59:15 +02:00
raid56.h btrfs: constify map parameter for nr_parity_stripes and nr_data_stripes 2019-07-01 13:34:58 +02:00
rcu-string.h btrfs: replace GPL boilerplate by SPDX -- headers 2018-04-12 16:29:46 +02:00
reada.c btrfs: Make reada_tree_block_flagged private 2019-09-09 14:59:11 +02:00
ref-verify.c Wimplicit-fallthrough patches for 5.2-rc1 2019-05-07 12:48:10 -07:00
ref-verify.h btrfs: ref-verify: Use btrfs_ref to refactor btrfs_ref_tree_mod() 2019-04-29 19:02:49 +02:00
relocation.c btrfs: relocation: fix use-after-free on dead relocation roots 2019-09-25 15:23:42 +02:00
root-tree.c btrfs: rename the btrfs_calc_*_metadata_size helpers 2019-09-09 14:59:13 +02:00
scrub.c btrfs: move basic block_group definitions to their own header 2019-09-09 14:59:03 +02:00
send.c btrfs: Relinquish CPUs in btrfs_compare_trees 2019-09-09 14:59:20 +02:00
send.h btrfs: replace GPL boilerplate by SPDX -- headers 2018-04-12 16:29:46 +02:00
space-info.c btrfs: add enospc debug messages for ticket failure 2019-09-09 14:59:19 +02:00
space-info.h btrfs: rename btrfs_space_info_add_old_bytes 2019-09-09 14:59:18 +02:00
struct-funcs.c btrfs: tie extent buffer and it's token together 2019-09-09 14:59:16 +02:00
super.c btrfs: move sysfs declarations out of ctree.h 2019-09-09 14:59:06 +02:00
sysfs.c btrfs: sysfs: move helper macros to sysfs.c 2019-09-09 14:59:08 +02:00
sysfs.h btrfs: sysfs: move helper macros to sysfs.c 2019-09-09 14:59:08 +02:00
transaction.c btrfs: move cond_wake_up functions out of ctree 2019-09-09 14:59:15 +02:00
transaction.h Btrfs: fix deadlock between fiemap and transaction commits 2019-07-30 18:25:12 +02:00
tree-checker.c btrfs: Detect unbalanced tree with empty leaf before crashing btree operations 2019-09-09 14:59:14 +02:00
tree-checker.h btrfs: get fs_info from eb in btrfs_check_chunk_valid 2019-04-29 19:02:39 +02:00
tree-defrag.c btrfs: open code now trivial btrfs_set_lock_blocking 2019-02-25 14:13:27 +01:00
tree-log.c btrfs: fix incorrect updating of log root tree 2019-10-01 18:41:02 +02:00
tree-log.h btrfs: get fs_info from trans in btrfs_set_log_full_commit 2019-04-29 19:02:41 +02:00
ulist.c btrfs: replace GPL boilerplate by SPDX -- sources 2018-04-12 16:29:51 +02:00
ulist.h btrfs: replace GPL boilerplate by SPDX -- headers 2018-04-12 16:29:46 +02:00
uuid-tree.c btrfs: remove unused parameter fs_info from btrfs_extend_item 2019-04-29 19:02:50 +02:00
volumes.c btrfs: fix balance convert to single on 32-bit host CPUs 2019-10-01 19:37:29 +02:00
volumes.h btrfs: reset device stat using btrfs_dev_stat_set 2019-09-09 14:59:06 +02:00
xattr.c Btrfs: fix failure to persist compression property xattr deletion on fsync 2019-06-17 16:37:17 +02:00
xattr.h btrfs: cleanup btrfs_setxattr_trans and drop transaction parameter 2019-04-29 19:02:44 +02:00
zlib.c btrfs: compression: replace set_level callbacks by a common helper 2019-09-09 14:59:11 +02:00
zstd.c btrfs: move cond_wake_up functions out of ctree 2019-09-09 14:59:15 +02:00