====================================================== WARNING: possible circular locking dependency detected 6.3.0-rc6-syzkaller-00183-ga7a55e27ad72 #0 Not tainted ------------------------------------------------------ kswapd0/111 is trying to acquire lock: ffff88804810ab98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: do_writepages+0x1a8/0x640 mm/page-writeback.c:2551 but task is already holding lock: ffffffff8c8e7420 (fs_reclaim){+.+.}-{0:0}, at: set_task_reclaim_state mm/vmscan.c:200 [inline] ffffffff8c8e7420 (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: -> #1 (fs_reclaim){+.+.}-{0:0}: __fs_reclaim_acquire mm/page_alloc.c:4717 [inline] fs_reclaim_acquire+0x11d/0x160 mm/page_alloc.c:4731 might_alloc include/linux/sched/mm.h:271 [inline] slab_pre_alloc_hook mm/slab.h:728 [inline] slab_alloc_node mm/slub.c:3434 [inline] slab_alloc mm/slub.c:3460 [inline] __kmem_cache_alloc_lru mm/slub.c:3467 [inline] kmem_cache_alloc+0x43/0x3b0 mm/slub.c:3476 kmem_cache_zalloc include/linux/slab.h:710 [inline] ext4_init_io_end+0x27/0x180 fs/ext4/page-io.c:278 ext4_do_writepages+0xbea/0x31e0 fs/ext4/inode.c:2824 ext4_writepages+0x27c/0x5e0 fs/ext4/inode.c:2964 do_writepages+0x1a8/0x640 mm/page-writeback.c:2551 __writeback_single_inode+0x121/0xdc0 fs/fs-writeback.c:1600 writeback_sb_inodes+0x54d/0xe70 fs/fs-writeback.c:1891 __writeback_inodes_wb+0xc6/0x280 fs/fs-writeback.c:1962 wb_writeback+0x7e9/0xa50 fs/fs-writeback.c:2067 wb_check_background_flush fs/fs-writeback.c:2133 [inline] wb_do_writeback fs/fs-writeback.c:2221 [inline] wb_workfn+0x8b0/0xfc0 fs/fs-writeback.c:2248 process_one_work+0x991/0x15c0 kernel/workqueue.c:2390 worker_thread+0x669/0x1090 kernel/workqueue.c:2537 kthread+0x2e8/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 -> #0 (&sbi->s_writepages_rwsem){++++}-{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] ext4_writepages+0x1a9/0x5e0 fs/ext4/inode.c:2963 do_writepages+0x1a8/0x640 mm/page-writeback.c:2551 filemap_fdatawrite_wbc mm/filemap.c:390 [inline] filemap_fdatawrite_wbc+0x147/0x1b0 mm/filemap.c:380 __filemap_fdatawrite_range+0xb8/0xf0 mm/filemap.c:423 jbd2_journal_begin_ordered_truncate+0x12b/0x190 fs/jbd2/transaction.c:2783 ext4_begin_ordered_truncate fs/ext4/inode.c:134 [inline] ext4_evict_inode+0xe4d/0x1ca0 fs/ext4/inode.c:220 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: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(&sbi->s_writepages_rwsem); lock(fs_reclaim); lock(&sbi->s_writepages_rwsem); *** DEADLOCK *** 3 locks held by kswapd0/111: #0: ffffffff8c8e7420 (fs_reclaim){+.+.}-{0:0}, at: set_task_reclaim_state mm/vmscan.c:200 [inline] #0: ffffffff8c8e7420 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x170/0x1ac0 mm/vmscan.c:7338 #1: ffffffff8c89e190 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab_memcg mm/vmscan.c:895 [inline] #1: ffffffff8c89e190 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0x2a0/0x660 mm/vmscan.c:1001 #2: ffff88804810c0e0 (&type->s_umount_key#32){++++}-{3:3}, at: trylock_super fs/super.c:414 [inline] #2: ffff88804810c0e0 (&type->s_umount_key#32){++++}-{3:3}, at: super_cache_scan+0x70/0x590 fs/super.c:79 stack backtrace: CPU: 3 PID: 111 Comm: kswapd0 Not tainted 6.3.0-rc6-syzkaller-00183-ga7a55e27ad72 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 Call Trace: __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] ext4_writepages+0x1a9/0x5e0 fs/ext4/inode.c:2963 do_writepages+0x1a8/0x640 mm/page-writeback.c:2551 filemap_fdatawrite_wbc mm/filemap.c:390 [inline] filemap_fdatawrite_wbc+0x147/0x1b0 mm/filemap.c:380 __filemap_fdatawrite_range+0xb8/0xf0 mm/filemap.c:423 jbd2_journal_begin_ordered_truncate+0x12b/0x190 fs/jbd2/transaction.c:2783 ext4_begin_ordered_truncate fs/ext4/inode.c:134 [inline] ext4_evict_inode+0xe4d/0x1ca0 fs/ext4/inode.c:220 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