======================================================
WARNING: possible circular locking dependency detected
6.9.0-rc4-syzkaller-00266-g977b1ef51866 #0 Not tainted
------------------------------------------------------
kswapd0/81 is trying to acquire lock:
ffff888076ffce98 (&xfs_nondir_ilock_class#3){++++}-{3:3}, at: xfs_reclaim_inode fs/xfs/xfs_icache.c:945 [inline]
ffff888076ffce98 (&xfs_nondir_ilock_class#3){++++}-{3:3}, at: xfs_icwalk_process_inode fs/xfs/xfs_icache.c:1631 [inline]
ffff888076ffce98 (&xfs_nondir_ilock_class#3){++++}-{3:3}, at: xfs_icwalk_ag+0x120e/0x1ad0 fs/xfs/xfs_icache.c:1713

but task is already holding lock:
ffffffff8e428e80 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6782 [inline]
ffffffff8e428e80 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xb20/0x30c0 mm/vmscan.c:7164

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (fs_reclaim){+.+.}-{0:0}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
       __fs_reclaim_acquire mm/page_alloc.c:3698 [inline]
       fs_reclaim_acquire+0x88/0x140 mm/page_alloc.c:3712
       might_alloc include/linux/sched/mm.h:312 [inline]
       slab_pre_alloc_hook mm/slub.c:3746 [inline]
       slab_alloc_node mm/slub.c:3827 [inline]
       kmalloc_trace+0x47/0x360 mm/slub.c:3992
       kmalloc include/linux/slab.h:628 [inline]
       add_stack_record_to_list mm/page_owner.c:177 [inline]
       inc_stack_record_count mm/page_owner.c:219 [inline]
       __set_page_owner+0x561/0x810 mm/page_owner.c:334
       set_page_owner include/linux/page_owner.h:32 [inline]
       post_alloc_hook+0x1ea/0x210 mm/page_alloc.c:1534
       prep_new_page mm/page_alloc.c:1541 [inline]
       get_page_from_freelist+0x3410/0x35b0 mm/page_alloc.c:3317
       __alloc_pages+0x256/0x6c0 mm/page_alloc.c:4575
       __alloc_pages_node include/linux/gfp.h:238 [inline]
       alloc_pages_node include/linux/gfp.h:261 [inline]
       alloc_slab_page+0x5f/0x160 mm/slub.c:2175
       allocate_slab mm/slub.c:2338 [inline]
       new_slab+0x84/0x2f0 mm/slub.c:2391
       ___slab_alloc+0xc73/0x1260 mm/slub.c:3525
       __slab_alloc mm/slub.c:3610 [inline]
       __slab_alloc_node mm/slub.c:3663 [inline]
       slab_alloc_node mm/slub.c:3835 [inline]
       kmem_cache_alloc+0x252/0x340 mm/slub.c:3852
       kmem_cache_zalloc include/linux/slab.h:739 [inline]
       xfs_btree_alloc_cursor fs/xfs/libxfs/xfs_btree.h:679 [inline]
       xfs_refcountbt_init_cursor+0x65/0x2a0 fs/xfs/libxfs/xfs_refcount_btree.c:367
       xfs_reflink_find_shared fs/xfs/xfs_reflink.c:147 [inline]
       xfs_reflink_trim_around_shared+0x53a/0x9d0 fs/xfs/xfs_reflink.c:194
       xfs_bmap_trim_cow fs/xfs/xfs_reflink.c:242 [inline]
       xfs_find_trim_cow_extent+0x380/0x4d0 fs/xfs/xfs_reflink.c:332
       xfs_reflink_allocate_cow+0x147/0xec0 fs/xfs/xfs_reflink.c:537
       xfs_direct_write_iomap_begin+0x7ce/0x1660 fs/xfs/xfs_iomap.c:829
       iomap_iter+0x691/0xf60 fs/iomap/iter.c:91
       __iomap_dio_rw+0xdec/0x2370 fs/iomap/direct-io.c:659
       iomap_dio_rw+0x46/0xa0 fs/iomap/direct-io.c:749
       xfs_file_dio_write_aligned+0x1a0/0x2c0 fs/xfs/xfs_file.c:608
       xfs_file_dio_write fs/xfs/xfs_file.c:720 [inline]
       xfs_file_write_iter+0x50d/0x620 fs/xfs/xfs_file.c:856
       call_write_iter include/linux/fs.h:2110 [inline]
       iter_file_splice_write+0xbd7/0x14e0 fs/splice.c:743
       do_splice_from fs/splice.c:941 [inline]
       direct_splice_actor+0x11e/0x220 fs/splice.c:1164
       splice_direct_to_actor+0x58e/0xc90 fs/splice.c:1108
       do_splice_direct_actor fs/splice.c:1207 [inline]
       do_splice_direct+0x28c/0x3e0 fs/splice.c:1233
       do_sendfile+0x56d/0xdc0 fs/read_write.c:1295
       __do_sys_sendfile64 fs/read_write.c:1362 [inline]
       __se_sys_sendfile64+0x17c/0x1e0 fs/read_write.c:1348
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&xfs_nondir_ilock_class#3){++++}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869
       __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
       down_write_nested+0x3d/0x50 kernel/locking/rwsem.c:1695
       xfs_reclaim_inode fs/xfs/xfs_icache.c:945 [inline]
       xfs_icwalk_process_inode fs/xfs/xfs_icache.c:1631 [inline]
       xfs_icwalk_ag+0x120e/0x1ad0 fs/xfs/xfs_icache.c:1713
       xfs_icwalk fs/xfs/xfs_icache.c:1762 [inline]
       xfs_reclaim_inodes_nr+0x257/0x360 fs/xfs/xfs_icache.c:1011
       super_cache_scan+0x40f/0x4b0 fs/super.c:227
       do_shrink_slab+0x705/0x1160 mm/shrinker.c:435
       shrink_slab+0x1092/0x14d0 mm/shrinker.c:662
       shrink_node_memcgs mm/vmscan.c:5875 [inline]
       shrink_node+0x11f5/0x2d60 mm/vmscan.c:5908
       kswapd_shrink_node mm/vmscan.c:6704 [inline]
       balance_pgdat mm/vmscan.c:6895 [inline]
       kswapd+0x1a25/0x30c0 mm/vmscan.c:7164
       kthread+0x2f0/0x390 kernel/kthread.c:388
       ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(fs_reclaim);
                               lock(&xfs_nondir_ilock_class#3);
                               lock(fs_reclaim);
  lock(&xfs_nondir_ilock_class#3);

 *** DEADLOCK ***

2 locks held by kswapd0/81:
 #0: ffffffff8e428e80 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6782 [inline]
 #0: ffffffff8e428e80 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xb20/0x30c0 mm/vmscan.c:7164
 #1: ffff8881943c40e0 (&type->s_umount_key#51){++++}-{3:3}, at: super_trylock_shared fs/super.c:561 [inline]
 #1: ffff8881943c40e0 (&type->s_umount_key#51){++++}-{3:3}, at: super_cache_scan+0x94/0x4b0 fs/super.c:196

stack backtrace:
CPU: 0 PID: 81 Comm: kswapd0 Not tainted 6.9.0-rc4-syzkaller-00266-g977b1ef51866 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 check_noncircular+0x36a/0x4a0 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+0x18cb/0x58e0 kernel/locking/lockdep.c:3869
 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
 down_write_nested+0x3d/0x50 kernel/locking/rwsem.c:1695
 xfs_reclaim_inode fs/xfs/xfs_icache.c:945 [inline]
 xfs_icwalk_process_inode fs/xfs/xfs_icache.c:1631 [inline]
 xfs_icwalk_ag+0x120e/0x1ad0 fs/xfs/xfs_icache.c:1713
 xfs_icwalk fs/xfs/xfs_icache.c:1762 [inline]
 xfs_reclaim_inodes_nr+0x257/0x360 fs/xfs/xfs_icache.c:1011
 super_cache_scan+0x40f/0x4b0 fs/super.c:227
 do_shrink_slab+0x705/0x1160 mm/shrinker.c:435
 shrink_slab+0x1092/0x14d0 mm/shrinker.c:662
 shrink_node_memcgs mm/vmscan.c:5875 [inline]
 shrink_node+0x11f5/0x2d60 mm/vmscan.c:5908
 kswapd_shrink_node mm/vmscan.c:6704 [inline]
 balance_pgdat mm/vmscan.c:6895 [inline]
 kswapd+0x1a25/0x30c0 mm/vmscan.c:7164
 kthread+0x2f0/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
------------[ cut here ]------------
WARNING: CPU: 0 PID: 81 at fs/ext4/inode.c:5156 ext4_write_inode+0x627/0x6f0 fs/ext4/inode.c:5156
Modules linked in:
CPU: 0 PID: 81 Comm: kswapd0 Not tainted 6.9.0-rc4-syzkaller-00266-g977b1ef51866 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:ext4_write_inode+0x627/0x6f0 fs/ext4/inode.c:5156
Code: ff ff ff 4d 85 ff 74 12 e8 56 d0 3f ff 4c 89 ff e8 ee 80 c3 ff e9 cf fd ff ff e8 44 d0 3f ff e9 c5 fd ff ff e8 3a d0 3f ff 90 <0f> 0b 90 e9 b7 fd ff ff e8 2c d0 3f ff e9 76 fd ff ff 44 89 f1 80
RSP: 0018:ffffc900020bee20 EFLAGS: 00010293
RAX: ffffffff82563036 RBX: 0000000000000800 RCX: ffff888018769e00
RDX: 0000000000000000 RSI: 0000000000000800 RDI: 0000000000000000
RBP: ffffc900020bef10 R08: ffffffff82562ad2 R09: 1ffffffff1f4f6d5
R10: dffffc0000000000 R11: ffffffff82562a10 R12: 0000000000220840
R13: 1ffff92000417dc8 R14: 0000000000000000 R15: ffff888018769e00
FS:  0000000000000000(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb6049542b0 CR3: 0000000068690000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 write_inode fs/fs-writeback.c:1498 [inline]
 __writeback_single_inode+0x6b9/0x10b0 fs/fs-writeback.c:1715
 writeback_single_inode+0x21b/0x7a0 fs/fs-writeback.c:1771
 write_inode_now+0x1d1/0x260 fs/fs-writeback.c:2813
 iput_final fs/inode.c:1728 [inline]
 iput+0x5d7/0x930 fs/inode.c:1767
 __dentry_kill+0x20d/0x630 fs/dcache.c:603
 dput+0x19f/0x2b0 fs/dcache.c:845
 ovl_destroy_inode+0x44/0x160 fs/overlayfs/super.c:181
 destroy_inode fs/inode.c:311 [inline]
 evict+0x549/0x630 fs/inode.c:682
 __dentry_kill+0x20d/0x630 fs/dcache.c:603
 shrink_kill+0xa9/0x2c0 fs/dcache.c:1048
 shrink_dentry_list+0x2c0/0x5b0 fs/dcache.c:1075
 prune_dcache_sb+0x10f/0x180 fs/dcache.c:1156
 super_cache_scan+0x34f/0x4b0 fs/super.c:221
 do_shrink_slab+0x705/0x1160 mm/shrinker.c:435
 shrink_slab_memcg mm/shrinker.c:548 [inline]
 shrink_slab+0x883/0x14d0 mm/shrinker.c:626
 shrink_node_memcgs mm/vmscan.c:5875 [inline]
 shrink_node+0x11f5/0x2d60 mm/vmscan.c:5908
 kswapd_shrink_node mm/vmscan.c:6704 [inline]
 balance_pgdat mm/vmscan.c:6895 [inline]
 kswapd+0x1a25/0x30c0 mm/vmscan.c:7164
 kthread+0x2f0/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>