====================================================== WARNING: possible circular locking dependency detected 6.3.0-rc3-syzkaller #0 Not tainted ------------------------------------------------------ kswapd0/100 is trying to acquire lock: ffff88801e636b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: do_writepages+0x1a8/0x640 mm/page-writeback.c:2551 but task is already holding lock: ffffffff8c8e1280 (fs_reclaim){+.+.}-{0:0}, at: set_task_reclaim_state mm/vmscan.c:200 [inline] ffffffff8c8e1280 (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:4716 [inline] fs_reclaim_acquire+0x11d/0x160 mm/page_alloc.c:4730 might_alloc include/linux/sched/mm.h:271 [inline] slab_pre_alloc_hook mm/slab.h:728 [inline] slab_alloc_node mm/slab.c:3241 [inline] slab_alloc mm/slab.c:3266 [inline] __kmem_cache_alloc_lru mm/slab.c:3443 [inline] kmem_cache_alloc+0x3d/0x3f0 mm/slab.c:3452 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 __writeback_single_inode+0x121/0xdc0 fs/fs-writeback.c:1600 writeback_single_inode+0x2ad/0x590 fs/fs-writeback.c:1721 write_inode_now+0x16e/0x1e0 fs/fs-writeback.c:2757 iput_final fs/inode.c:1735 [inline] iput.part.0+0x408/0x740 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 kswapd0/100: #0: ffffffff8c8e1280 (fs_reclaim){+.+.}-{0:0}, at: set_task_reclaim_state mm/vmscan.c:200 [inline] #0: ffffffff8c8e1280 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x170/0x1ac0 mm/vmscan.c:7338 #1: ffffffff8c8980b0 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab_memcg mm/vmscan.c:895 [inline] #1: ffffffff8c8980b0 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0x2a0/0x660 mm/vmscan.c:1001 #2: ffff88801e6300e0 (&type->s_umount_key#50){++++}-{3:3}, at: trylock_super fs/super.c:414 [inline] #2: ffff88801e6300e0 (&type->s_umount_key#50){++++}-{3:3}, at: super_cache_scan+0x70/0x590 fs/super.c:79 stack backtrace: CPU: 1 PID: 100 Comm: kswapd0 Not tainted 6.3.0-rc3-syzkaller #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 __writeback_single_inode+0x121/0xdc0 fs/fs-writeback.c:1600 writeback_single_inode+0x2ad/0x590 fs/fs-writeback.c:1721 write_inode_now+0x16e/0x1e0 fs/fs-writeback.c:2757 iput_final fs/inode.c:1735 [inline] iput.part.0+0x408/0x740 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 ------------[ cut here ]------------ WARNING: CPU: 1 PID: 100 at fs/ext4/inode.c:5325 ext4_write_inode+0x337/0x590 fs/ext4/inode.c:5325 Modules linked in: CPU: 1 PID: 100 Comm: kswapd0 Not tainted 6.3.0-rc3-syzkaller #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 RIP: 0010:ext4_write_inode+0x337/0x590 fs/ext4/inode.c:5325 Code: b6 04 02 84 c0 74 08 3c 03 0f 8e 3d 02 00 00 8b b5 b0 06 00 00 4c 89 f7 e8 c6 94 12 00 41 89 c4 e9 ed fd ff ff e8 e9 4e 5a ff <0f> 0b 45 31 e4 e9 de fd ff ff e8 da 4e 5a ff 48 89 ef 48 8d 74 24 RSP: 0018:ffffc90000c87360 EFLAGS: 00010293 RAX: 0000000000000000 RBX: 1ffff92000190e6c RCX: 0000000000000000 RDX: ffff8880169700c0 RSI: ffffffff8227b6c7 RDI: 0000000000000005 RBP: ffff8880283852f0 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000800 R11: 3e4b5341542f3c20 R12: 0000000000000800 R13: ffffc90000c874e0 R14: dffffc0000000000 R15: ffff888028385318 FS: 0000000000000000(0000) GS:ffff88802ca80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe7eabfe718 CR3: 00000000738f6000 CR4: 0000000000150ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: write_inode fs/fs-writeback.c:1453 [inline] __writeback_single_inode+0x9f8/0xdc0 fs/fs-writeback.c:1665 writeback_single_inode+0x2ad/0x590 fs/fs-writeback.c:1721 write_inode_now+0x16e/0x1e0 fs/fs-writeback.c:2757 iput_final fs/inode.c:1735 [inline] iput.part.0+0x408/0x740 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