====================================================== WARNING: possible circular locking dependency detected 6.13.0-syzkaller-09760-g69e858e0b8b2 #0 Not tainted ------------------------------------------------------ kswapd0/75 is trying to acquire lock: ffff888053281c68 (&bc->lock){+.+.}-{4:4}, at: bch2_btree_cache_scan+0x184/0xec0 fs/bcachefs/btree_cache.c:482 but task is already holding lock: ffffffff8ea390a0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6881 [inline] ffffffff8ea390a0 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xb9f/0x3b10 mm/vmscan.c:7259 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (fs_reclaim){+.+.}-{0:0}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 __fs_reclaim_acquire mm/page_alloc.c:3853 [inline] fs_reclaim_acquire+0x88/0x130 mm/page_alloc.c:3867 might_alloc include/linux/sched/mm.h:318 [inline] slab_pre_alloc_hook mm/slub.c:4066 [inline] slab_alloc_node mm/slub.c:4144 [inline] __do_kmalloc_node mm/slub.c:4293 [inline] __kmalloc_noprof+0xae/0x4c0 mm/slub.c:4306 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1037 [inline] pcpu_mem_zalloc mm/percpu.c:510 [inline] pcpu_alloc_chunk mm/percpu.c:1430 [inline] pcpu_create_chunk+0x57/0xbc0 mm/percpu-vm.c:338 pcpu_balance_populated mm/percpu.c:2063 [inline] pcpu_balance_workfn+0xc4d/0xd40 mm/percpu.c:2200 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317 worker_thread+0x870/0xd30 kernel/workqueue.c:3398 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 -> #1 (pcpu_alloc_mutex){+.+.}-{4:4}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730 pcpu_alloc_noprof+0x293/0x1760 mm/percpu.c:1782 __six_lock_init+0x104/0x150 fs/bcachefs/six.c:876 bch2_btree_lock_init+0x38/0x100 fs/bcachefs/btree_locking.c:12 bch2_btree_node_mem_alloc+0x565/0x16f0 fs/bcachefs/btree_cache.c:807 __bch2_btree_node_alloc fs/bcachefs/btree_update_interior.c:304 [inline] bch2_btree_reserve_get+0x2df/0x1890 fs/bcachefs/btree_update_interior.c:532 bch2_btree_update_start+0xe56/0x14e0 fs/bcachefs/btree_update_interior.c:1230 bch2_btree_split_leaf+0x121/0x880 fs/bcachefs/btree_update_interior.c:1851 bch2_trans_commit_error+0x212/0x1380 fs/bcachefs/btree_trans_commit.c:908 __bch2_trans_commit+0x812b/0x97a0 fs/bcachefs/btree_trans_commit.c:1085 bch2_trans_commit fs/bcachefs/btree_update.h:183 [inline] bch2_trans_mark_metadata_bucket+0x47a/0x17b0 fs/bcachefs/buckets.c:1043 bch2_trans_mark_metadata_sectors fs/bcachefs/buckets.c:1060 [inline] __bch2_trans_mark_dev_sb fs/bcachefs/buckets.c:1100 [inline] bch2_trans_mark_dev_sb+0x3f6/0x820 fs/bcachefs/buckets.c:1128 bch2_trans_mark_dev_sbs_flags+0x6be/0x720 fs/bcachefs/buckets.c:1138 bch2_fs_initialize+0xba0/0x1610 fs/bcachefs/recovery.c:1150 bch2_fs_start+0x36d/0x610 fs/bcachefs/super.c:1031 bch2_fs_get_tree+0xd8d/0x1740 fs/bcachefs/fs.c:2203 vfs_get_tree+0x90/0x2b0 fs/super.c:1814 do_new_mount+0x2be/0xb40 fs/namespace.c:3560 do_mount fs/namespace.c:3900 [inline] __do_sys_mount fs/namespace.c:4111 [inline] __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&bc->lock){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3163 [inline] check_prevs_add kernel/locking/lockdep.c:3282 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730 bch2_btree_cache_scan+0x184/0xec0 fs/bcachefs/btree_cache.c:482 do_shrink_slab+0x72d/0x1160 mm/shrinker.c:437 shrink_slab+0x1093/0x14d0 mm/shrinker.c:664 shrink_one+0x43b/0x850 mm/vmscan.c:4863 shrink_many mm/vmscan.c:4924 [inline] lru_gen_shrink_node mm/vmscan.c:5002 [inline] shrink_node+0x37c5/0x3e50 mm/vmscan.c:5973 kswapd_shrink_node mm/vmscan.c:6802 [inline] balance_pgdat mm/vmscan.c:6994 [inline] kswapd+0x20f3/0x3b10 mm/vmscan.c:7259 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 other info that might help us debug this: Chain exists of: &bc->lock --> pcpu_alloc_mutex --> fs_reclaim Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(pcpu_alloc_mutex); lock(fs_reclaim); lock(&bc->lock); *** DEADLOCK *** 1 lock held by kswapd0/75: #0: ffffffff8ea390a0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6881 [inline] #0: ffffffff8ea390a0 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xb9f/0x3b10 mm/vmscan.c:7259 stack backtrace: CPU: 0 UID: 0 PID: 75 Comm: kswapd0 Not tainted 6.13.0-syzkaller-09760-g69e858e0b8b2 #0 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 lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2076 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2208 check_prev_add kernel/locking/lockdep.c:3163 [inline] check_prevs_add kernel/locking/lockdep.c:3282 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730 bch2_btree_cache_scan+0x184/0xec0 fs/bcachefs/btree_cache.c:482 do_shrink_slab+0x72d/0x1160 mm/shrinker.c:437 shrink_slab+0x1093/0x14d0 mm/shrinker.c:664 shrink_one+0x43b/0x850 mm/vmscan.c:4863 shrink_many mm/vmscan.c:4924 [inline] lru_gen_shrink_node mm/vmscan.c:5002 [inline] shrink_node+0x37c5/0x3e50 mm/vmscan.c:5973 kswapd_shrink_node mm/vmscan.c:6802 [inline] balance_pgdat mm/vmscan.c:6994 [inline] kswapd+0x20f3/0x3b10 mm/vmscan.c:7259 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244