====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ kswapd0/74 is trying to acquire lock: ffff8880420f4098 (&type->lock_class){+.+.}-{4:4}, at: keyring_clear+0xaf/0x240 security/keys/keyring.c:1658 but task is already holding lock: ffffffff8de44f40 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:7015 [inline] ffffffff8de44f40 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0x951/0x2800 mm/vmscan.c:7389 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (fs_reclaim){+.+.}-{0:0}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __fs_reclaim_acquire mm/page_alloc.c:4269 [inline] fs_reclaim_acquire+0x72/0x100 mm/page_alloc.c:4283 might_alloc include/linux/sched/mm.h:318 [inline] slab_pre_alloc_hook mm/slub.c:4897 [inline] slab_alloc_node mm/slub.c:5221 [inline] __kmalloc_cache_noprof+0x40/0x6f0 mm/slub.c:5719 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] assoc_array_insert+0x92/0x2f90 lib/assoc_array.c:980 __key_link_begin+0xd6/0x1f0 security/keys/keyring.c:1317 __key_create_or_update+0x41a/0xa30 security/keys/key.c:877 key_create_or_update+0x42/0x60 security/keys/key.c:1021 x509_load_certificate_list+0x145/0x280 crypto/asymmetric_keys/x509_loader.c:31 do_one_initcall+0x233/0x820 init/main.c:1283 do_initcall_level+0x104/0x190 init/main.c:1345 do_initcalls+0x59/0xa0 init/main.c:1361 kernel_init_freeable+0x334/0x4b0 init/main.c:1593 kernel_init+0x1d/0x1d0 init/main.c:1483 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #0 (&type->lock_class){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 down_write+0x96/0x1f0 kernel/locking/rwsem.c:1590 keyring_clear+0xaf/0x240 security/keys/keyring.c:1658 fscrypt_put_master_key+0xca/0x190 fs/crypto/keyring.c:80 put_crypt_info+0x26d/0x310 fs/crypto/keysetup.c:573 fscrypt_put_encryption_info+0xf6/0x140 fs/crypto/keysetup.c:787 ext4_clear_inode+0x170/0x2f0 fs/ext4/super.c:1527 ext4_evict_inode+0xa67/0xee0 fs/ext4/inode.c:321 evict+0x504/0x9c0 fs/inode.c:810 dispose_list fs/inode.c:852 [inline] prune_icache_sb+0x21b/0x2c0 fs/inode.c:1000 super_cache_scan+0x39b/0x4b0 fs/super.c:224 do_shrink_slab+0x6ef/0x1110 mm/shrinker.c:437 shrink_slab_memcg mm/shrinker.c:550 [inline] shrink_slab+0x7ef/0x10d0 mm/shrinker.c:628 shrink_one+0x28a/0x7c0 mm/vmscan.c:4955 shrink_many mm/vmscan.c:5016 [inline] lru_gen_shrink_node mm/vmscan.c:5094 [inline] shrink_node+0x315d/0x3780 mm/vmscan.c:6081 kswapd_shrink_node mm/vmscan.c:6941 [inline] balance_pgdat mm/vmscan.c:7124 [inline] kswapd+0x147c/0x2800 mm/vmscan.c:7389 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 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 kswapd0/74: #0: ffffffff8de44f40 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:7015 [inline] #0: ffffffff8de44f40 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0x951/0x2800 mm/vmscan.c:7389 #1: ffff8880115840e0 (&type->s_umount_key#31){++++}-{4:4}, at: super_trylock_shared fs/super.c:562 [inline] #1: ffff8880115840e0 (&type->s_umount_key#31){++++}-{4:4}, at: super_cache_scan+0x91/0x4b0 fs/super.c:197 stack backtrace: CPU: 0 UID: 0 PID: 74 Comm: kswapd0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043 check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 down_write+0x96/0x1f0 kernel/locking/rwsem.c:1590 keyring_clear+0xaf/0x240 security/keys/keyring.c:1658 fscrypt_put_master_key+0xca/0x190 fs/crypto/keyring.c:80 put_crypt_info+0x26d/0x310 fs/crypto/keysetup.c:573 fscrypt_put_encryption_info+0xf6/0x140 fs/crypto/keysetup.c:787 ext4_clear_inode+0x170/0x2f0 fs/ext4/super.c:1527 ext4_evict_inode+0xa67/0xee0 fs/ext4/inode.c:321 evict+0x504/0x9c0 fs/inode.c:810 dispose_list fs/inode.c:852 [inline] prune_icache_sb+0x21b/0x2c0 fs/inode.c:1000 super_cache_scan+0x39b/0x4b0 fs/super.c:224 do_shrink_slab+0x6ef/0x1110 mm/shrinker.c:437 shrink_slab_memcg mm/shrinker.c:550 [inline] shrink_slab+0x7ef/0x10d0 mm/shrinker.c:628 shrink_one+0x28a/0x7c0 mm/vmscan.c:4955 shrink_many mm/vmscan.c:5016 [inline] lru_gen_shrink_node mm/vmscan.c:5094 [inline] shrink_node+0x315d/0x3780 mm/vmscan.c:6081 kswapd_shrink_node mm/vmscan.c:6941 [inline] balance_pgdat mm/vmscan.c:7124 [inline] kswapd+0x147c/0x2800 mm/vmscan.c:7389 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245