syzbot

======================================================
WARNING: possible circular locking dependency detected
6.9.0-rc6-syzkaller-00005-gb947cc5bf6d7 #0 Not tainted
------------------------------------------------------
kswapd1/89 is trying to acquire lock:
ffff88807eafa018 (&xfs_dir_ilock_class){++++}-{3:3}, at: xfs_reclaim_inode fs/xfs/xfs_icache.c:945 [inline]
ffff88807eafa018 (&xfs_dir_ilock_class){++++}-{3:3}, at: xfs_icwalk_process_inode fs/xfs/xfs_icache.c:1631 [inline]
ffff88807eafa018 (&xfs_dir_ilock_class){++++}-{3:3}, at: xfs_icwalk_ag+0x120e/0x1ad0 fs/xfs/xfs_icache.c:1713

but task is already holding lock:
ffffffff8e428d00 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6782 [inline]
ffffffff8e428d00 (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_mpol+0x3e8/0x680 mm/mempolicy.c:2264
       stack_depot_save_flags+0x666/0x830 lib/stackdepot.c:635
       kasan_save_stack mm/kasan/common.c:48 [inline]
       kasan_save_track+0x51/0x80 mm/kasan/common.c:68
       poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
       __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387
       kasan_kmalloc include/linux/kasan.h:211 [inline]
       __do_kmalloc_node mm/slub.c:3966 [inline]
       __kmalloc+0x233/0x4a0 mm/slub.c:3979
       kmalloc include/linux/slab.h:632 [inline]
       kzalloc include/linux/slab.h:749 [inline]
       xfs_dabuf_map+0x18b/0xc50 fs/xfs/libxfs/xfs_da_btree.c:2547
       xfs_da_read_buf+0x19b/0x470 fs/xfs/libxfs/xfs_da_btree.c:2670
       xfs_dir3_block_read+0x92/0x1a0 fs/xfs/libxfs/xfs_dir2_block.c:145
       xfs_dir2_block_lookup_int+0x109/0x7d0 fs/xfs/libxfs/xfs_dir2_block.c:700
       xfs_dir2_block_lookup+0x19a/0x630 fs/xfs/libxfs/xfs_dir2_block.c:650
       xfs_dir_lookup+0x633/0xaf0 fs/xfs/libxfs/xfs_dir2.c:399
       xfs_lookup+0x298/0x550 fs/xfs/xfs_inode.c:640
       xfs_vn_lookup+0x192/0x290 fs/xfs/xfs_iops.c:303
       lookup_one_qstr_excl+0x11f/0x260 fs/namei.c:1607
       do_renameat2+0x670/0x13f0 fs/namei.c:4978
       __do_sys_renameat2 fs/namei.c:5071 [inline]
       __se_sys_renameat2 fs/namei.c:5068 [inline]
       __x64_sys_renameat2+0xd2/0xf0 fs/namei.c:5068
       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_dir_ilock_class){++++}-{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_dir_ilock_class);
                               lock(fs_reclaim);
  lock(&xfs_dir_ilock_class);

 *** DEADLOCK ***

2 locks held by kswapd1/89:
 #0: ffffffff8e428d00 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6782 [inline]
 #0: ffffffff8e428d00 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xb20/0x30c0 mm/vmscan.c:7164
 #1: ffff8880734340e0 (&type->s_umount_key#59){++++}-{3:3}, at: super_trylock_shared fs/super.c:561 [inline]
 #1: ffff8880734340e0 (&type->s_umount_key#59){++++}-{3:3}, at: super_cache_scan+0x94/0x4b0 fs/super.c:196

stack backtrace:
CPU: 0 PID: 89 Comm: kswapd1 Not tainted 6.9.0-rc6-syzkaller-00005-gb947cc5bf6d7 #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>