syzbot

======================================================
WARNING: possible circular locking dependency detected
6.9.0-rc7-syzkaller-00117-g448b3fe5a0ea #0 Not tainted
------------------------------------------------------
kswapd1/88 is trying to acquire lock:
ffff88801c763758 (&type->lock_class){+.+.}-{3:3}, at: keyring_clear+0xa0/0x270 security/keys/keyring.c:1655

but task is already holding lock:
ffffffff8db30360 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x166/0x19a0 mm/vmscan.c:6782

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (fs_reclaim){+.+.}-{0:0}:
       __fs_reclaim_acquire mm/page_alloc.c:3698 [inline]
       fs_reclaim_acquire+0x102/0x160 mm/page_alloc.c:3712
       might_alloc include/linux/sched/mm.h:312 [inline]
       slab_pre_alloc_hook mm/slub.c:3752 [inline]
       slab_alloc_node mm/slub.c:3833 [inline]
       kmalloc_trace+0x51/0x340 mm/slub.c:3998
       kmalloc include/linux/slab.h:628 [inline]
       kzalloc include/linux/slab.h:749 [inline]
       assoc_array_insert+0x10a/0x3140 lib/assoc_array.c:980
       __key_link_begin+0xf5/0x260 security/keys/keyring.c:1314
       __key_create_or_update+0x4e5/0xe10 security/keys/key.c:861
       key_create_or_update+0x42/0x60 security/keys/key.c:1005
       x509_load_certificate_list+0x1dd/0x280 crypto/asymmetric_keys/x509_loader.c:31
       do_one_initcall+0x128/0x700 init/main.c:1245
       do_initcall_level init/main.c:1307 [inline]
       do_initcalls init/main.c:1323 [inline]
       do_basic_setup init/main.c:1342 [inline]
       kernel_init_freeable+0x69d/0xca0 init/main.c:1555
       kernel_init+0x1c/0x2b0 init/main.c:1444
       ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #0 (&type->lock_class){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain kernel/locking/lockdep.c:3869 [inline]
       __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
       lock_acquire kernel/locking/lockdep.c:5754 [inline]
       lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719
       down_write+0x3a/0x50 kernel/locking/rwsem.c:1579
       keyring_clear+0xa0/0x270 security/keys/keyring.c:1655
       fscrypt_put_master_key fs/crypto/keyring.c:79 [inline]
       fscrypt_put_master_key+0x111/0x1e0 fs/crypto/keyring.c:67
       fscrypt_put_master_key_activeref.part.0+0x259/0x340 fs/crypto/keyring.c:125
       fscrypt_put_master_key_activeref+0x86/0xb0 include/linux/refcount.h:271
       put_crypt_info+0x1ff/0x380 fs/crypto/keysetup.c:548
       fscrypt_put_encryption_info+0x38/0x80 fs/crypto/keysetup.c:753
       ext4_clear_inode+0x17d/0x230 fs/ext4/super.c:1536
       ext4_evict_inode+0x246/0x17d0 fs/ext4/inode.c:318
       evict+0x2ed/0x6c0 fs/inode.c:667
       iput_final fs/inode.c:1741 [inline]
       iput.part.0+0x5a8/0x7f0 fs/inode.c:1767
       iput+0x5c/0x80 fs/inode.c:1757
       dentry_unlink_inode+0x295/0x440 fs/dcache.c:400
       __dentry_kill+0x1d0/0x600 fs/dcache.c:603
       shrink_kill fs/dcache.c:1048 [inline]
       shrink_dentry_list+0x140/0x5d0 fs/dcache.c:1075
       prune_dcache_sb+0xeb/0x150 fs/dcache.c:1156
       super_cache_scan+0x32a/0x550 fs/super.c:221
       do_shrink_slab+0x44f/0x11c0 mm/shrinker.c:435
       shrink_slab_memcg mm/shrinker.c:548 [inline]
       shrink_slab+0xa87/0x1310 mm/shrinker.c:626
       shrink_one+0x493/0x7c0 mm/vmscan.c:4774
       shrink_many mm/vmscan.c:4835 [inline]
       lru_gen_shrink_node mm/vmscan.c:4935 [inline]
       shrink_node+0x231f/0x3a80 mm/vmscan.c:5894
       kswapd_shrink_node mm/vmscan.c:6704 [inline]
       balance_pgdat+0x9a0/0x19a0 mm/vmscan.c:6895
       kswapd+0x5ea/0xbf0 mm/vmscan.c:7164
       kthread+0x2c1/0x3a0 kernel/kthread.c:388
       ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(fs_reclaim);
                               lock(&type->lock_class);
                               lock(fs_reclaim);
  lock(&type->lock_class);

 *** DEADLOCK ***

2 locks held by kswapd1/88:
 #0: ffffffff8db30360 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x166/0x19a0 mm/vmscan.c:6782
 #1: ffff8882371880e0 (&type->s_umount_key#52){++++}-{3:3}, at: super_trylock_shared fs/super.c:561 [inline]
 #1: ffff8882371880e0 (&type->s_umount_key#52){++++}-{3:3}, at: super_cache_scan+0x96/0x550 fs/super.c:196

stack backtrace:
CPU: 0 PID: 88 Comm: kswapd1 Not tainted 6.9.0-rc7-syzkaller-00117-g448b3fe5a0ea #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
 check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2187
 check_prev_add kernel/locking/lockdep.c:3134 [inline]
 check_prevs_add kernel/locking/lockdep.c:3253 [inline]
 validate_chain kernel/locking/lockdep.c:3869 [inline]
 __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
 lock_acquire kernel/locking/lockdep.c:5754 [inline]
 lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719
 down_write+0x3a/0x50 kernel/locking/rwsem.c:1579
 keyring_clear+0xa0/0x270 security/keys/keyring.c:1655
 fscrypt_put_master_key fs/crypto/keyring.c:79 [inline]
 fscrypt_put_master_key+0x111/0x1e0 fs/crypto/keyring.c:67
 fscrypt_put_master_key_activeref.part.0+0x259/0x340 fs/crypto/keyring.c:125
 fscrypt_put_master_key_activeref+0x86/0xb0 include/linux/refcount.h:271
 put_crypt_info+0x1ff/0x380 fs/crypto/keysetup.c:548
 fscrypt_put_encryption_info+0x38/0x80 fs/crypto/keysetup.c:753
 ext4_clear_inode+0x17d/0x230 fs/ext4/super.c:1536
 ext4_evict_inode+0x246/0x17d0 fs/ext4/inode.c:318
 evict+0x2ed/0x6c0 fs/inode.c:667
 iput_final fs/inode.c:1741 [inline]
 iput.part.0+0x5a8/0x7f0 fs/inode.c:1767
 iput+0x5c/0x80 fs/inode.c:1757
 dentry_unlink_inode+0x295/0x440 fs/dcache.c:400
 __dentry_kill+0x1d0/0x600 fs/dcache.c:603
 shrink_kill fs/dcache.c:1048 [inline]
 shrink_dentry_list+0x140/0x5d0 fs/dcache.c:1075
 prune_dcache_sb+0xeb/0x150 fs/dcache.c:1156
 super_cache_scan+0x32a/0x550 fs/super.c:221
 do_shrink_slab+0x44f/0x11c0 mm/shrinker.c:435
 shrink_slab_memcg mm/shrinker.c:548 [inline]
 shrink_slab+0xa87/0x1310 mm/shrinker.c:626
 shrink_one+0x493/0x7c0 mm/vmscan.c:4774
 shrink_many mm/vmscan.c:4835 [inline]
 lru_gen_shrink_node mm/vmscan.c:4935 [inline]
 shrink_node+0x231f/0x3a80 mm/vmscan.c:5894
 kswapd_shrink_node mm/vmscan.c:6704 [inline]
 balance_pgdat+0x9a0/0x19a0 mm/vmscan.c:6895
 kswapd+0x5ea/0xbf0 mm/vmscan.c:7164
 kthread+0x2c1/0x3a0 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>