====================================================== WARNING: possible circular locking dependency detected 6.8.0-rc2-syzkaller #0 Not tainted ------------------------------------------------------ kswapd0/109 is trying to acquire lock: ffff888022f6a950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x10d9/0x15e0 fs/jbd2/transaction.c:463 but task is already holding lock: ffffffff8d319ca0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x160/0x1a90 mm/vmscan.c:6771 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (fs_reclaim){+.+.}-{0:0}: __fs_reclaim_acquire mm/page_alloc.c:3692 [inline] fs_reclaim_acquire+0x100/0x150 mm/page_alloc.c:3706 might_alloc include/linux/sched/mm.h:303 [inline] slab_pre_alloc_hook mm/slub.c:3761 [inline] slab_alloc_node mm/slub.c:3842 [inline] kmem_cache_alloc+0x4f/0x320 mm/slub.c:3867 kmem_cache_zalloc include/linux/slab.h:701 [inline] __es_alloc_extent fs/ext4/extents_status.c:483 [inline] ext4_es_insert_delayed_block+0x542/0x760 fs/ext4/extents_status.c:2090 ext4_insert_delayed_block fs/ext4/inode.c:1674 [inline] ext4_da_map_blocks fs/ext4/inode.c:1762 [inline] ext4_da_get_block_prep+0x850/0x1340 fs/ext4/inode.c:1823 ext4_block_write_begin+0x3da/0xee0 fs/ext4/inode.c:1053 ext4_da_write_begin+0x40a/0x8c0 fs/ext4/inode.c:2900 generic_perform_write+0x278/0x600 mm/filemap.c:3930 ext4_buffered_write_iter+0x11f/0x3c0 fs/ext4/file.c:299 ext4_file_write_iter+0x819/0x1950 fs/ext4/file.c:698 call_write_iter include/linux/fs.h:2085 [inline] iter_file_splice_write+0x8fe/0x10a0 fs/splice.c:743 do_splice_from fs/splice.c:941 [inline] direct_splice_actor+0x19b/0x6c0 fs/splice.c:1164 splice_direct_to_actor+0x347/0xa30 fs/splice.c:1108 do_splice_direct_actor fs/splice.c:1207 [inline] do_splice_direct+0x17e/0x250 fs/splice.c:1233 do_sendfile+0xaa8/0xdb0 fs/read_write.c:1295 __do_sys_sendfile64 fs/read_write.c:1362 [inline] __se_sys_sendfile64 fs/read_write.c:1348 [inline] __x64_sys_sendfile64+0x1d6/0x220 fs/read_write.c:1348 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd3/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b -> #1 (&ei->i_data_sem){++++}-{3:3}: down_write+0x3a/0x50 kernel/locking/rwsem.c:1579 ext4_map_blocks+0x5a7/0x1770 fs/ext4/inode.c:614 mpage_map_one_extent fs/ext4/inode.c:2169 [inline] mpage_map_and_submit_extent fs/ext4/inode.c:2222 [inline] ext4_do_writepages+0x184e/0x3350 fs/ext4/inode.c:2685 ext4_writepages+0x30c/0x780 fs/ext4/inode.c:2774 do_writepages+0x1b4/0x690 mm/page-writeback.c:2553 __writeback_single_inode+0x158/0xe90 fs/fs-writeback.c:1625 writeback_sb_inodes+0x599/0x1080 fs/fs-writeback.c:1916 __writeback_inodes_wb+0xff/0x2d0 fs/fs-writeback.c:1987 wb_writeback+0x7f8/0xaa0 fs/fs-writeback.c:2094 wb_check_background_flush fs/fs-writeback.c:2164 [inline] wb_do_writeback fs/fs-writeback.c:2252 [inline] wb_workfn+0x87c/0xfe0 fs/fs-writeback.c:2279 process_one_work+0x886/0x15d0 kernel/workqueue.c:2633 process_scheduled_works kernel/workqueue.c:2706 [inline] worker_thread+0x8b9/0x1290 kernel/workqueue.c:2787 kthread+0x2c6/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242 -> #0 (jbd2_handle){++++}-{0:0}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2445/0x3b30 kernel/locking/lockdep.c:5137 lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1ae/0x520 kernel/locking/lockdep.c:5719 start_this_handle+0x10ff/0x15e0 fs/jbd2/transaction.c:463 jbd2__journal_start+0x391/0x840 fs/jbd2/transaction.c:520 __ext4_journal_start_sb+0x343/0x5d0 fs/ext4/ext4_jbd2.c:112 __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline] ext4_dirty_inode+0xa1/0x130 fs/ext4/inode.c:5969 __mark_inode_dirty+0x1e0/0xd60 fs/fs-writeback.c:2452 mark_inode_dirty_sync include/linux/fs.h:2388 [inline] iput.part.0+0x5b/0x7b0 fs/inode.c:1762 iput+0x5c/0x80 fs/inode.c:1755 dentry_unlink_inode+0x292/0x430 fs/dcache.c:400 __dentry_kill+0x1ca/0x5f0 fs/dcache.c:603 shrink_kill fs/dcache.c:1048 [inline] shrink_dentry_list+0x140/0x5d0 fs/dcache.c:1075 prune_dcache_sb+0xeb/0x150 fs/dcache.c:1156 super_cache_scan+0x327/0x540 fs/super.c:221 do_shrink_slab+0x428/0x1120 mm/shrinker.c:435 shrink_slab+0x18a/0x1310 mm/shrinker.c:662 shrink_one+0x48f/0x7b0 mm/vmscan.c:4767 shrink_many mm/vmscan.c:4828 [inline] lru_gen_shrink_node mm/vmscan.c:4929 [inline] shrink_node+0x2149/0x3740 mm/vmscan.c:5888 kswapd_shrink_node mm/vmscan.c:6693 [inline] balance_pgdat+0x9d2/0x1a90 mm/vmscan.c:6883 kswapd+0x5be/0xbf0 mm/vmscan.c:7143 kthread+0x2c6/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242 other info that might help us debug this: Chain exists of: jbd2_handle --> &ei->i_data_sem --> fs_reclaim Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(&ei->i_data_sem); lock(fs_reclaim); rlock(jbd2_handle); *** DEADLOCK *** 2 locks held by kswapd0/109: #0: ffffffff8d319ca0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x160/0x1a90 mm/vmscan.c:6771 #1: ffff888022f760e0 (&type->s_umount_key#50){++++}-{3:3}, at: super_trylock_shared fs/super.c:566 [inline] #1: ffff888022f760e0 (&type->s_umount_key#50){++++}-{3:3}, at: super_cache_scan+0x96/0x540 fs/super.c:196 stack backtrace: CPU: 2 PID: 109 Comm: kswapd0 Not tainted 6.8.0-rc2-syzkaller #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 check_noncircular+0x317/0x400 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2445/0x3b30 kernel/locking/lockdep.c:5137 lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1ae/0x520 kernel/locking/lockdep.c:5719 start_this_handle+0x10ff/0x15e0 fs/jbd2/transaction.c:463 jbd2__journal_start+0x391/0x840 fs/jbd2/transaction.c:520 __ext4_journal_start_sb+0x343/0x5d0 fs/ext4/ext4_jbd2.c:112 __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline] ext4_dirty_inode+0xa1/0x130 fs/ext4/inode.c:5969 __mark_inode_dirty+0x1e0/0xd60 fs/fs-writeback.c:2452 mark_inode_dirty_sync include/linux/fs.h:2388 [inline] iput.part.0+0x5b/0x7b0 fs/inode.c:1762 iput+0x5c/0x80 fs/inode.c:1755 dentry_unlink_inode+0x292/0x430 fs/dcache.c:400 __dentry_kill+0x1ca/0x5f0 fs/dcache.c:603 shrink_kill fs/dcache.c:1048 [inline] shrink_dentry_list+0x140/0x5d0 fs/dcache.c:1075 prune_dcache_sb+0xeb/0x150 fs/dcache.c:1156 super_cache_scan+0x327/0x540 fs/super.c:221 do_shrink_slab+0x428/0x1120 mm/shrinker.c:435 shrink_slab+0x18a/0x1310 mm/shrinker.c:662 shrink_one+0x48f/0x7b0 mm/vmscan.c:4767 shrink_many mm/vmscan.c:4828 [inline] lru_gen_shrink_node mm/vmscan.c:4929 [inline] shrink_node+0x2149/0x3740 mm/vmscan.c:5888 kswapd_shrink_node mm/vmscan.c:6693 [inline] balance_pgdat+0x9d2/0x1a90 mm/vmscan.c:6883 kswapd+0x5be/0xbf0 mm/vmscan.c:7143 kthread+0x2c6/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242