====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ kswapd0/69 is trying to acquire lock: ffff888000a34090 (&type->lock_class){+.+.}-{4:4}, at: keyring_clear+0xae/0x250 security/keys/keyring.c:1659 but task is already holding lock: ffffffff8ea869a0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:7084 [inline] ffffffff8ea869a0 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0x9b6/0x31c0 mm/vmscan.c:7462 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:4329 [inline] fs_reclaim_acquire+0x71/0x100 mm/page_alloc.c:4343 might_alloc include/linux/sched/mm.h:317 [inline] slab_pre_alloc_hook mm/slub.c:4565 [inline] slab_alloc_node mm/slub.c:4925 [inline] __kmalloc_cache_noprof+0x61/0x660 mm/slub.c:5511 _kmalloc_noprof include/linux/slab.h:969 [inline] _kzalloc_noprof include/linux/slab.h:1290 [inline] assoc_array_insert+0x90/0x2f60 lib/assoc_array.c:978 __key_link_begin+0xd6/0x1f0 security/keys/keyring.c:1318 __key_create_or_update+0x449/0xa80 security/keys/key.c:877 key_create_or_update+0x42/0x60 security/keys/key.c:1021 x509_load_certificate_list+0x13d/0x280 crypto/asymmetric_keys/x509_loader.c:31 do_one_initcall+0x250/0x870 init/main.c:1347 do_initcall_level+0x10a/0x1a0 init/main.c:1409 do_initcalls+0x59/0xa0 init/main.c:1425 kernel_init_freeable+0x29d/0x3e0 init/main.c:1658 kernel_init+0x1d/0x1d0 init/main.c:1548 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 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 kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1520/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 down_write+0x96/0x200 kernel/locking/rwsem.c:1631 keyring_clear+0xae/0x250 security/keys/keyring.c:1659 fscrypt_put_master_key+0xca/0x190 fs/crypto/keyring.c:80 put_crypt_info+0x248/0x2b0 fs/crypto/keysetup.c:573 fscrypt_put_encryption_info+0xf6/0x140 fs/crypto/keysetup.c:785 ext4_evict_inode+0xbc8/0x10c0 fs/ext4/inode.c:334 evict+0x624/0xb50 fs/inode.c:825 dentry_kill+0x1b9/0x880 fs/dcache.c:826 shrink_kill fs/dcache.c:1275 [inline] shrink_dentry_list+0x209/0x310 fs/dcache.c:1292 prune_dcache_sb+0x119/0x180 fs/dcache.c:1374 super_cache_scan+0x35c/0x4a0 fs/super.c:223 do_shrink_slab+0x6d0/0x10e0 mm/shrinker.c:434 shrink_slab_memcg mm/shrinker.c:551 [inline] shrink_slab+0x838/0x1220 mm/shrinker.c:629 shrink_one+0x2a2/0x730 mm/vmscan.c:5026 shrink_many mm/vmscan.c:5087 [inline] lru_gen_shrink_node mm/vmscan.c:5165 [inline] shrink_node+0x3303/0x3b60 mm/vmscan.c:6154 kswapd_shrink_node mm/vmscan.c:7008 [inline] balance_pgdat mm/vmscan.c:7186 [inline] kswapd+0x17b6/0x31c0 mm/vmscan.c:7462 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 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 kswapd0/69: #0: ffffffff8ea869a0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:7084 [inline] #0: ffffffff8ea869a0 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0x9b6/0x31c0 mm/vmscan.c:7462 #1: ffff888036e620d8 (&type->s_umount_key#33){++++}-{4:4}, at: super_trylock_shared fs/super.c:566 [inline] #1: ffff888036e620d8 (&type->s_umount_key#33){++++}-{4:4}, at: super_cache_scan+0x91/0x4a0 fs/super.c:198 stack backtrace: CPU: 0 UID: 0 PID: 69 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 04/01/2014 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043 check_noncircular+0x12e/0x150 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 kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1520/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 down_write+0x96/0x200 kernel/locking/rwsem.c:1631 keyring_clear+0xae/0x250 security/keys/keyring.c:1659 fscrypt_put_master_key+0xca/0x190 fs/crypto/keyring.c:80 put_crypt_info+0x248/0x2b0 fs/crypto/keysetup.c:573 fscrypt_put_encryption_info+0xf6/0x140 fs/crypto/keysetup.c:785 ext4_evict_inode+0xbc8/0x10c0 fs/ext4/inode.c:334 evict+0x624/0xb50 fs/inode.c:825 dentry_kill+0x1b9/0x880 fs/dcache.c:826 shrink_kill fs/dcache.c:1275 [inline] shrink_dentry_list+0x209/0x310 fs/dcache.c:1292 prune_dcache_sb+0x119/0x180 fs/dcache.c:1374 super_cache_scan+0x35c/0x4a0 fs/super.c:223 do_shrink_slab+0x6d0/0x10e0 mm/shrinker.c:434 shrink_slab_memcg mm/shrinker.c:551 [inline] shrink_slab+0x838/0x1220 mm/shrinker.c:629 shrink_one+0x2a2/0x730 mm/vmscan.c:5026 shrink_many mm/vmscan.c:5087 [inline] lru_gen_shrink_node mm/vmscan.c:5165 [inline] shrink_node+0x3303/0x3b60 mm/vmscan.c:6154 kswapd_shrink_node mm/vmscan.c:7008 [inline] balance_pgdat mm/vmscan.c:7186 [inline] kswapd+0x17b6/0x31c0 mm/vmscan.c:7462 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245