syzbot

======================================================
WARNING: possible circular locking dependency detected
6.3.0-rc3-syzkaller-00031-g1e760fa3596e #0 Not tainted
------------------------------------------------------
kswapd0/100 is trying to acquire lock:
ffff888041852650 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x6b0 fs/inode.c:665

but task is already holding lock:
ffffffff8c8e1280 (fs_reclaim){+.+.}-{0:0}, at: set_task_reclaim_state mm/vmscan.c:200 [inline]
ffffffff8c8e1280 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x170/0x1ac0 mm/vmscan.c:7338

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (fs_reclaim){+.+.}-{0:0}:
       __fs_reclaim_acquire mm/page_alloc.c:4716 [inline]
       fs_reclaim_acquire+0x11d/0x160 mm/page_alloc.c:4730
       might_alloc include/linux/sched/mm.h:271 [inline]
       slab_pre_alloc_hook mm/slab.h:728 [inline]
       slab_alloc_node mm/slab.c:3241 [inline]
       __kmem_cache_alloc_node+0x3b/0x3f0 mm/slab.c:3541
       kmalloc_node_trace+0x21/0xd0 mm/slab_common.c:1074
       kmalloc_node include/linux/slab.h:606 [inline]
       kzalloc_node include/linux/slab.h:731 [inline]
       mempool_create_node mm/mempool.c:272 [inline]
       mempool_create+0x52/0xc0 mm/mempool.c:261
       mempool_create_page_pool include/linux/mempool.h:112 [inline]
       fscrypt_initialize+0x8a/0xa0 fs/crypto/crypto.c:332
       fscrypt_setup_encryption_info+0xef/0xeb0 fs/crypto/keysetup.c:563
       fscrypt_get_encryption_info+0x375/0x450 fs/crypto/keysetup.c:668
       fscrypt_setup_filename+0x23c/0xec0 fs/crypto/fname.c:458
       __fscrypt_prepare_lookup+0x2c/0xf0 fs/crypto/hooks.c:100
       fscrypt_prepare_lookup include/linux/fscrypt.h:935 [inline]
       ext4_fname_prepare_lookup+0x1be/0x200 fs/ext4/crypto.c:46
       ext4_lookup_entry fs/ext4/namei.c:1744 [inline]
       ext4_lookup fs/ext4/namei.c:1819 [inline]
       ext4_lookup+0x131/0x700 fs/ext4/namei.c:1810
       lookup_open.isra.0+0x944/0x1400 fs/namei.c:3394
       open_last_lookups fs/namei.c:3484 [inline]
       path_openat+0x975/0x2750 fs/namei.c:3712
       do_filp_open+0x1ba/0x410 fs/namei.c:3742
       do_sys_openat2+0x16d/0x4c0 fs/open.c:1348
       do_sys_open fs/open.c:1364 [inline]
       __do_sys_open fs/open.c:1372 [inline]
       __se_sys_open fs/open.c:1368 [inline]
       __x64_sys_open+0x11d/0x1c0 fs/open.c:1368
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #2 (fscrypt_init_mutex){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x12f/0x1350 kernel/locking/mutex.c:747
       fscrypt_initialize+0x40/0xa0 fs/crypto/crypto.c:326
       fscrypt_setup_encryption_info+0xef/0xeb0 fs/crypto/keysetup.c:563
       fscrypt_get_encryption_info+0x375/0x450 fs/crypto/keysetup.c:668
       fscrypt_setup_filename+0x23c/0xec0 fs/crypto/fname.c:458
       ext4_fname_setup_filename+0x8c/0x110 fs/ext4/crypto.c:28
       ext4_add_entry+0x3aa/0xe30 fs/ext4/namei.c:2379
       ext4_rename+0x1a6a/0x2790 fs/ext4/namei.c:3915
       ext4_rename2+0x1c7/0x270 fs/ext4/namei.c:4200
       vfs_rename+0xef6/0x17a0 fs/namei.c:4772
       do_renameat2+0xb62/0xc90 fs/namei.c:4923
       __do_sys_renameat2 fs/namei.c:4956 [inline]
       __se_sys_renameat2 fs/namei.c:4953 [inline]
       __x64_sys_renameat2+0xe8/0x120 fs/namei.c:4953
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #1 (jbd2_handle){++++}-{0:0}:
       start_this_handle+0xfe7/0x14e0 fs/jbd2/transaction.c:463
       jbd2__journal_start+0x390/0x850 fs/jbd2/transaction.c:520
       __ext4_journal_start_sb+0x411/0x5d0 fs/ext4/ext4_jbd2.c:111
       ext4_sample_last_mounted fs/ext4/file.c:851 [inline]
       ext4_file_open+0x618/0xbf0 fs/ext4/file.c:880
       do_dentry_open+0x6cc/0x13f0 fs/open.c:920
       do_open fs/namei.c:3560 [inline]
       path_openat+0x1baa/0x2750 fs/namei.c:3715
       do_filp_open+0x1ba/0x410 fs/namei.c:3742
       do_sys_openat2+0x16d/0x4c0 fs/open.c:1348
       do_sys_open fs/open.c:1364 [inline]
       __do_sys_openat fs/open.c:1380 [inline]
       __se_sys_openat fs/open.c:1375 [inline]
       __x64_sys_openat+0x143/0x1f0 fs/open.c:1375
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (sb_internal){.+.+}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3098 [inline]
       check_prevs_add kernel/locking/lockdep.c:3217 [inline]
       validate_chain kernel/locking/lockdep.c:3832 [inline]
       __lock_acquire+0x2ec7/0x5d40 kernel/locking/lockdep.c:5056
       lock_acquire kernel/locking/lockdep.c:5669 [inline]
       lock_acquire+0x1af/0x520 kernel/locking/lockdep.c:5634
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1477 [inline]
       sb_start_intwrite include/linux/fs.h:1599 [inline]
       ext4_evict_inode+0x114b/0x1ca0 fs/ext4/inode.c:240
       evict+0x2ed/0x6b0 fs/inode.c:665
       iput_final fs/inode.c:1748 [inline]
       iput.part.0+0x50a/0x740 fs/inode.c:1774
       iput+0x5c/0x80 fs/inode.c:1764
       dentry_unlink_inode+0x2b1/0x460 fs/dcache.c:401
       __dentry_kill+0x3c0/0x640 fs/dcache.c:607
       shrink_dentry_list+0x12c/0x4f0 fs/dcache.c:1201
       prune_dcache_sb+0xeb/0x150 fs/dcache.c:1282
       super_cache_scan+0x33a/0x590 fs/super.c:104
       do_shrink_slab+0x428/0xaa0 mm/vmscan.c:853
       shrink_slab_memcg mm/vmscan.c:922 [inline]
       shrink_slab+0x388/0x660 mm/vmscan.c:1001
       shrink_one+0x502/0x810 mm/vmscan.c:5343
       shrink_many mm/vmscan.c:5394 [inline]
       lru_gen_shrink_node mm/vmscan.c:5511 [inline]
       shrink_node+0x2064/0x35f0 mm/vmscan.c:6459
       kswapd_shrink_node mm/vmscan.c:7262 [inline]
       balance_pgdat+0xa02/0x1ac0 mm/vmscan.c:7452
       kswapd+0x677/0xd60 mm/vmscan.c:7712
       kthread+0x2e8/0x3a0 kernel/kthread.c:376
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

other info that might help us debug this:

Chain exists of:
  sb_internal --> fscrypt_init_mutex --> fs_reclaim

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(fs_reclaim);
                               lock(fscrypt_init_mutex);
                               lock(fs_reclaim);
  lock(sb_internal);

 *** DEADLOCK ***

3 locks held by kswapd0/100:
 #0: ffffffff8c8e1280 (fs_reclaim){+.+.}-{0:0}, at: set_task_reclaim_state mm/vmscan.c:200 [inline]
 #0: ffffffff8c8e1280 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x170/0x1ac0 mm/vmscan.c:7338
 #1: ffffffff8c8980b0 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab_memcg mm/vmscan.c:895 [inline]
 #1: ffffffff8c8980b0 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0x2a0/0x660 mm/vmscan.c:1001
 #2: ffff8880418520e0 (&type->s_umount_key#50){++++}-{3:3}, at: trylock_super fs/super.c:414 [inline]
 #2: ffff8880418520e0 (&type->s_umount_key#50){++++}-{3:3}, at: super_cache_scan+0x70/0x590 fs/super.c:79

stack backtrace:
CPU: 1 PID: 100 Comm: kswapd0 Not tainted 6.3.0-rc3-syzkaller-00031-g1e760fa3596e #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2178
 check_prev_add kernel/locking/lockdep.c:3098 [inline]
 check_prevs_add kernel/locking/lockdep.c:3217 [inline]
 validate_chain kernel/locking/lockdep.c:3832 [inline]
 __lock_acquire+0x2ec7/0x5d40 kernel/locking/lockdep.c:5056
 lock_acquire kernel/locking/lockdep.c:5669 [inline]
 lock_acquire+0x1af/0x520 kernel/locking/lockdep.c:5634
 percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
 __sb_start_write include/linux/fs.h:1477 [inline]
 sb_start_intwrite include/linux/fs.h:1599 [inline]
 ext4_evict_inode+0x114b/0x1ca0 fs/ext4/inode.c:240
 evict+0x2ed/0x6b0 fs/inode.c:665
 iput_final fs/inode.c:1748 [inline]
 iput.part.0+0x50a/0x740 fs/inode.c:1774
 iput+0x5c/0x80 fs/inode.c:1764
 dentry_unlink_inode+0x2b1/0x460 fs/dcache.c:401
 __dentry_kill+0x3c0/0x640 fs/dcache.c:607
 shrink_dentry_list+0x12c/0x4f0 fs/dcache.c:1201
 prune_dcache_sb+0xeb/0x150 fs/dcache.c:1282
 super_cache_scan+0x33a/0x590 fs/super.c:104
 do_shrink_slab+0x428/0xaa0 mm/vmscan.c:853
 shrink_slab_memcg mm/vmscan.c:922 [inline]
 shrink_slab+0x388/0x660 mm/vmscan.c:1001
 shrink_one+0x502/0x810 mm/vmscan.c:5343
 shrink_many mm/vmscan.c:5394 [inline]
 lru_gen_shrink_node mm/vmscan.c:5511 [inline]
 shrink_node+0x2064/0x35f0 mm/vmscan.c:6459
 kswapd_shrink_node mm/vmscan.c:7262 [inline]
 balance_pgdat+0xa02/0x1ac0 mm/vmscan.c:7452
 kswapd+0x677/0xd60 mm/vmscan.c:7712
 kthread+0x2e8/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>