Chao Yu 2d586a3f5b f2fs: quota: fix potential deadlock ... [ Upstream commit 9de71ede81e6d1a111fdd868b2d78d459fa77f80 ] xfstest generic/587 reports a deadlock issue as below: ====================================================== WARNING: possible circular locking dependency detected 5.14.0-rc1 #69 Not tainted ------------------------------------------------------ repquota/8606 is trying to acquire lock: ffff888022ac9320 (&sb->s_type->i_mutex_key#18){+.+.}-{3:3}, at: f2fs_quota_sync+0x207/0x300 [f2fs] but task is already holding lock: ffff8880084bcde8 (&sbi->quota_sem){.+.+}-{3:3}, at: f2fs_quota_sync+0x59/0x300 [f2fs] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&sbi->quota_sem){.+.+}-{3:3}: __lock_acquire+0x648/0x10b0 lock_acquire+0x128/0x470 down_read+0x3b/0x2a0 f2fs_quota_sync+0x59/0x300 [f2fs] f2fs_quota_on+0x48/0x100 [f2fs] do_quotactl+0x5e3/0xb30 __x64_sys_quotactl+0x23a/0x4e0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #1 (&sbi->cp_rwsem){++++}-{3:3}: __lock_acquire+0x648/0x10b0 lock_acquire+0x128/0x470 down_read+0x3b/0x2a0 f2fs_unlink+0x353/0x670 [f2fs] vfs_unlink+0x1c7/0x380 do_unlinkat+0x413/0x4b0 __x64_sys_unlinkat+0x50/0xb0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #0 (&sb->s_type->i_mutex_key#18){+.+.}-{3:3}: check_prev_add+0xdc/0xb30 validate_chain+0xa67/0xb20 __lock_acquire+0x648/0x10b0 lock_acquire+0x128/0x470 down_write+0x39/0xc0 f2fs_quota_sync+0x207/0x300 [f2fs] do_quotactl+0xaff/0xb30 __x64_sys_quotactl+0x23a/0x4e0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae other info that might help us debug this: Chain exists of: &sb->s_type->i_mutex_key#18 --> &sbi->cp_rwsem --> &sbi->quota_sem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sbi->quota_sem); lock(&sbi->cp_rwsem); lock(&sbi->quota_sem); lock(&sb->s_type->i_mutex_key#18); *** DEADLOCK *** 3 locks held by repquota/8606: #0: ffff88801efac0e0 (&type->s_umount_key#53){++++}-{3:3}, at: user_get_super+0xd9/0x190 #1: ffff8880084bc380 (&sbi->cp_rwsem){++++}-{3:3}, at: f2fs_quota_sync+0x3e/0x300 [f2fs] #2: ffff8880084bcde8 (&sbi->quota_sem){.+.+}-{3:3}, at: f2fs_quota_sync+0x59/0x300 [f2fs] stack backtrace: CPU: 6 PID: 8606 Comm: repquota Not tainted 5.14.0-rc1 #69 Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 Call Trace: dump_stack_lvl+0xce/0x134 dump_stack+0x17/0x20 print_circular_bug.isra.0.cold+0x239/0x253 check_noncircular+0x1be/0x1f0 check_prev_add+0xdc/0xb30 validate_chain+0xa67/0xb20 __lock_acquire+0x648/0x10b0 lock_acquire+0x128/0x470 down_write+0x39/0xc0 f2fs_quota_sync+0x207/0x300 [f2fs] do_quotactl+0xaff/0xb30 __x64_sys_quotactl+0x23a/0x4e0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f883b0b4efe The root cause is ABBA deadlock of inode lock and cp_rwsem, reorder locks in f2fs_quota_sync() as below to fix this issue: - lock inode - lock cp_rwsem - lock quota_sem Fixes: db6ec53b7e ("f2fs: add a rw_sem to cover quota flag changes") Signed-off-by: Chao Yu <chao@kernel.org> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>		2021-09-18 13:40:11 +02:00
..
acl.c	f2fs: clean up kvfree	2020-09-14 11:15:37 -07:00
acl.h	f2fs: Use the correct style for SPDX License Identifier	2020-05-08 06:55:55 -07:00
checkpoint.c	f2fs: avoid race condition for shrinker count	2021-01-06 14:56:54 +01:00
compress.c	f2fs: compress: fix to assign cc.cluster_idx correctly	2021-05-19 10:13:14 +02:00
data.c	f2fs: Prevent swap file in LFS mode	2021-07-14 16:55:43 +02:00
debug.c	f2fs: avoid race condition for shrinker count	2021-01-06 14:56:54 +01:00
dir.c	f2fs-for-5.10-rc1	2020-10-16 15:14:43 -07:00
extent_cache.c	f2fs: support 64-bits key in f2fs rb-tree node entry	2020-09-10 14:03:30 -07:00
f2fs.h	f2fs: fix to avoid racing on fsync_entry_slab by multi filesystem instances	2021-07-19 09:45:03 +02:00
file.c	f2fs: guarantee to write dirty data when enabling checkpoint back	2021-09-15 09:50:46 +02:00
gc.c	f2fs: atgc: fix to set default age threshold	2021-07-20 16:05:49 +02:00
gc.h	f2fs: support age threshold based garbage collection	2020-09-11 11:11:15 -07:00
hash.c	f2fs-for-5.8-rc1	2020-06-09 11:28:59 -07:00
inline.c	f2fs: fix a redundant call to f2fs_balance_fs if an error occurs	2021-05-19 10:13:00 +02:00
inode.c	f2fs: fix to set SBI_NEED_FSCK flag for inconsistent inode	2020-10-09 10:29:31 -07:00
Kconfig	f2fs: compress: support lzo-rle compress algorithm	2020-05-11 20:36:46 -07:00
Makefile	f2fs: support data compression	2020-01-17 16:48:07 -08:00
namei.c	f2fs: report correct st_size for encrypted symlinks	2021-09-08 08:48:59 +02:00
node.c	f2fs: fix to avoid out-of-bounds memory access	2021-05-11 14:47:34 +02:00
node.h	f2fs: avoid race condition for shrinker count	2021-01-06 14:56:54 +01:00
recovery.c	f2fs: fix to avoid racing on fsync_entry_slab by multi filesystem instances	2021-07-19 09:45:03 +02:00
segment.c	f2fs: fix to avoid accessing invalid fio in f2fs_allocate_data_block()	2021-05-19 10:13:02 +02:00
segment.h	f2fs: fix to avoid touching checkpointed data in get_victim()	2021-05-19 10:13:02 +02:00
shrinker.c	f2fs: avoid race condition for shrinker count	2021-01-06 14:56:54 +01:00
super.c	f2fs: quota: fix potential deadlock	2021-09-18 13:40:11 +02:00
sysfs.c	f2fs: Show casefolding support only when supported	2021-07-25 14:36:17 +02:00
trace.c	f2fs: do not use mutex lock in atomic context	2019-03-05 19:58:06 -08:00
trace.h	f2fs: Use the correct style for SPDX License Identifier	2020-05-08 06:55:55 -07:00
verity.c	f2fs: fix error handling in f2fs_end_enable_verity()	2021-05-11 14:47:34 +02:00
xattr.c	f2fs: clean up kvfree	2020-09-14 11:15:37 -07:00
xattr.h	f2fs: code cleanup by removing ifdef macro surrounding	2020-05-26 18:56:10 -07:00