syzbot

======================================================
WARNING: possible circular locking dependency detected
6.6.0-syzkaller-15477-g34f763262743 #0 Not tainted
------------------------------------------------------
kswapd0/108 is trying to acquire lock:
ffff888044d2c950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x10d6/0x15e0 fs/jbd2/transaction.c:463

but task is already holding lock:
ffffffff8d11d1a0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x1b4/0x1b80 mm/vmscan.c:6716

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:3693 [inline]
       fs_reclaim_acquire+0x100/0x150 mm/page_alloc.c:3707
       might_alloc include/linux/sched/mm.h:303 [inline]
       slab_pre_alloc_hook mm/slab.h:710 [inline]
       slab_alloc_node mm/slub.c:3460 [inline]
       slab_alloc mm/slub.c:3486 [inline]
       __kmem_cache_alloc_lru mm/slub.c:3493 [inline]
       kmem_cache_alloc+0x4f/0x380 mm/slub.c:3502
       kmem_cache_zalloc include/linux/slab.h:711 [inline]
       __es_alloc_extent fs/ext4/extents_status.c:483 [inline]
       ext4_es_insert_delayed_block+0x542/0x750 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:3918
       ext4_buffered_write_iter+0x11f/0x3c0 fs/ext4/file.c:299
       ext4_file_write_iter+0x819/0x1950 fs/ext4/file.c:696
       call_write_iter include/linux/fs.h:2020 [inline]
       new_sync_write fs/read_write.c:491 [inline]
       vfs_write+0x64f/0xdf0 fs/read_write.c:584
       ksys_write+0x12f/0x250 fs/read_write.c:637
       do_syscall_32_irqs_on arch/x86/entry/common.c:164 [inline]
       __do_fast_syscall_32+0x61/0xe0 arch/x86/entry/common.c:230
       do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:255
       entry_SYSENTER_compat_after_hwframe+0x70/0x7a

-> #1 (&ei->i_data_sem){++++}-{3:3}:
       down_write+0x93/0x200 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+0x1848/0x3340 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+0x158/0xe70 fs/fs-writeback.c:1625
       writeback_sb_inodes+0x599/0x1070 fs/fs-writeback.c:1916
       __writeback_inodes_wb+0xff/0x2d0 fs/fs-writeback.c:1987
       wb_writeback+0x7f8/0xa90 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+0x874/0xfd0 fs/fs-writeback.c:2279
       process_one_work+0x884/0x15c0 kernel/workqueue.c:2630
       process_scheduled_works kernel/workqueue.c:2703 [inline]
       worker_thread+0x8b9/0x1290 kernel/workqueue.c:2784
       kthread+0x33c/0x440 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:3868 [inline]
       __lock_acquire+0x2e3d/0x5de0 kernel/locking/lockdep.c:5136
       lock_acquire kernel/locking/lockdep.c:5753 [inline]
       lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5718
       start_this_handle+0x10fc/0x15e0 fs/jbd2/transaction.c:463
       jbd2__journal_start+0x391/0x690 fs/jbd2/transaction.c:520
       __ext4_journal_start_sb+0x40f/0x5c0 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:5962
       __mark_inode_dirty+0x1e0/0xd50 fs/fs-writeback.c:2452
       mark_inode_dirty_sync include/linux/fs.h:2311 [inline]
       iput.part.0+0x5b/0x7a0 fs/inode.c:1798
       iput+0x5c/0x80 fs/inode.c:1791
       dentry_unlink_inode+0x292/0x430 fs/dcache.c:401
       __dentry_kill+0x3b8/0x640 fs/dcache.c:607
       shrink_dentry_list+0x22b/0x7d0 fs/dcache.c:1201
       prune_dcache_sb+0xeb/0x150 fs/dcache.c:1282
       super_cache_scan+0x327/0x540 fs/super.c:228
       do_shrink_slab+0x428/0x1120 mm/shrinker.c:435
       shrink_slab_memcg mm/shrinker.c:548 [inline]
       shrink_slab+0xa83/0x1310 mm/shrinker.c:626
       shrink_one+0x4f7/0x700 mm/vmscan.c:4724
       shrink_many mm/vmscan.c:4776 [inline]
       lru_gen_shrink_node mm/vmscan.c:4893 [inline]
       shrink_node+0x20cd/0x3790 mm/vmscan.c:5833
       kswapd_shrink_node mm/vmscan.c:6638 [inline]
       balance_pgdat+0xa32/0x1b80 mm/vmscan.c:6828
       kswapd+0x5be/0xbf0 mm/vmscan.c:7088
       kthread+0x33c/0x440 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 kswapd0/108:
 #0: ffffffff8d11d1a0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x1b4/0x1b80 mm/vmscan.c:6716
 #1: ffff888044d2e0e0 (&type->s_umount_key#31){++++}-{3:3}, at: super_trylock_shared fs/super.c:610 [inline]
 #1: ffff888044d2e0e0 (&type->s_umount_key#31){++++}-{3:3}, at: super_cache_scan+0x96/0x540 fs/super.c:203

stack backtrace:
CPU: 1 PID: 108 Comm: kswapd0 Not tainted 6.6.0-syzkaller-15477-g34f763262743 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
 check_noncircular+0x311/0x3f0 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:3868 [inline]
 __lock_acquire+0x2e3d/0x5de0 kernel/locking/lockdep.c:5136
 lock_acquire kernel/locking/lockdep.c:5753 [inline]
 lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5718
 start_this_handle+0x10fc/0x15e0 fs/jbd2/transaction.c:463
 jbd2__journal_start+0x391/0x690 fs/jbd2/transaction.c:520
 __ext4_journal_start_sb+0x40f/0x5c0 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:5962
 __mark_inode_dirty+0x1e0/0xd50 fs/fs-writeback.c:2452
 mark_inode_dirty_sync include/linux/fs.h:2311 [inline]
 iput.part.0+0x5b/0x7a0 fs/inode.c:1798
 iput+0x5c/0x80 fs/inode.c:1791
 dentry_unlink_inode+0x292/0x430 fs/dcache.c:401
 __dentry_kill+0x3b8/0x640 fs/dcache.c:607
 shrink_dentry_list+0x22b/0x7d0 fs/dcache.c:1201
 prune_dcache_sb+0xeb/0x150 fs/dcache.c:1282
 super_cache_scan+0x327/0x540 fs/super.c:228
 do_shrink_slab+0x428/0x1120 mm/shrinker.c:435
 shrink_slab_memcg mm/shrinker.c:548 [inline]
 shrink_slab+0xa83/0x1310 mm/shrinker.c:626
 shrink_one+0x4f7/0x700 mm/vmscan.c:4724
 shrink_many mm/vmscan.c:4776 [inline]
 lru_gen_shrink_node mm/vmscan.c:4893 [inline]
 shrink_node+0x20cd/0x3790 mm/vmscan.c:5833
 kswapd_shrink_node mm/vmscan.c:6638 [inline]
 balance_pgdat+0xa32/0x1b80 mm/vmscan.c:6828
 kswapd+0x5be/0xbf0 mm/vmscan.c:7088
 kthread+0x33c/0x440 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
 </TASK>