syzbot

======================================================
WARNING: possible circular locking dependency detected
6.12.0-rc1-syzkaller-00330-gfc20a3e57247 #0 Not tainted
------------------------------------------------------
kswapd0/73 is trying to acquire lock:
ffff88803f654bd0 (&osb->nfs_sync_rwlock){.+.+}-{3:3}, at: ocfs2_nfs_sync_lock+0x109/0x260 fs/ocfs2/dlmglue.c:2876

but task is already holding lock:
ffffffff8ea37160 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6844 [inline]
ffffffff8ea37160 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xbf1/0x3700 mm/vmscan.c:7226

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (fs_reclaim){+.+.}-{0:0}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825
       __fs_reclaim_acquire mm/page_alloc.c:3834 [inline]
       fs_reclaim_acquire+0x88/0x140 mm/page_alloc.c:3848
       might_alloc include/linux/sched/mm.h:327 [inline]
       slab_pre_alloc_hook mm/slub.c:4036 [inline]
       slab_alloc_node mm/slub.c:4114 [inline]
       __kmalloc_cache_noprof+0x3d/0x2c0 mm/slub.c:4290
       kmalloc_noprof include/linux/slab.h:878 [inline]
       kzalloc_noprof include/linux/slab.h:1014 [inline]
       ocfs2_reserve_new_metadata_blocks+0x117/0x9c0 fs/ocfs2/suballoc.c:966
       ocfs2_mknod+0x143a/0x2b40 fs/ocfs2/namei.c:345
       ocfs2_mkdir+0x1ab/0x480 fs/ocfs2/namei.c:655
       vfs_mkdir+0x2f9/0x4f0 fs/namei.c:4257
       do_mkdirat+0x264/0x3a0 fs/namei.c:4280
       __do_sys_mkdirat fs/namei.c:4295 [inline]
       __se_sys_mkdirat fs/namei.c:4293 [inline]
       __x64_sys_mkdirat+0x87/0xa0 fs/namei.c:4293
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#2){+.+.}-{3:3}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825
       down_write+0x99/0x220 kernel/locking/rwsem.c:1577
       inode_lock include/linux/fs.h:815 [inline]
       ocfs2_remove_inode fs/ocfs2/inode.c:655 [inline]
       ocfs2_wipe_inode fs/ocfs2/inode.c:818 [inline]
       ocfs2_delete_inode fs/ocfs2/inode.c:1079 [inline]
       ocfs2_evict_inode+0x209f/0x4680 fs/ocfs2/inode.c:1216
       evict+0x4e8/0x9b0 fs/inode.c:723
       ocfs2_dentry_iput+0x232/0x380 fs/ocfs2/dcache.c:411
       __dentry_kill+0x20d/0x630 fs/dcache.c:615
       dput+0x19f/0x2b0 fs/dcache.c:857
       ovl_check_rename_whiteout fs/overlayfs/super.c:586 [inline]
       ovl_make_workdir fs/overlayfs/super.c:685 [inline]
       ovl_get_workdir+0xc6c/0x1920 fs/overlayfs/super.c:808
       ovl_fill_super+0x12a8/0x3560 fs/overlayfs/super.c:1376
       vfs_get_super fs/super.c:1280 [inline]
       get_tree_nodev+0xb7/0x140 fs/super.c:1299
       vfs_get_tree+0x90/0x2b0 fs/super.c:1800
       do_new_mount+0x2be/0xb40 fs/namespace.c:3507
       do_mount fs/namespace.c:3847 [inline]
       __do_sys_mount fs/namespace.c:4055 [inline]
       __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4032
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]){+.+.}-{3:3}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825
       down_write+0x99/0x220 kernel/locking/rwsem.c:1577
       inode_lock include/linux/fs.h:815 [inline]
       ocfs2_wipe_inode fs/ocfs2/inode.c:776 [inline]
       ocfs2_delete_inode fs/ocfs2/inode.c:1079 [inline]
       ocfs2_evict_inode+0x1b17/0x4680 fs/ocfs2/inode.c:1216
       evict+0x4e8/0x9b0 fs/inode.c:723
       ocfs2_dentry_iput+0x232/0x380 fs/ocfs2/dcache.c:411
       __dentry_kill+0x20d/0x630 fs/dcache.c:615
       dput+0x19f/0x2b0 fs/dcache.c:857
       ovl_check_rename_whiteout fs/overlayfs/super.c:586 [inline]
       ovl_make_workdir fs/overlayfs/super.c:685 [inline]
       ovl_get_workdir+0xc6c/0x1920 fs/overlayfs/super.c:808
       ovl_fill_super+0x12a8/0x3560 fs/overlayfs/super.c:1376
       vfs_get_super fs/super.c:1280 [inline]
       get_tree_nodev+0xb7/0x140 fs/super.c:1299
       vfs_get_tree+0x90/0x2b0 fs/super.c:1800
       do_new_mount+0x2be/0xb40 fs/namespace.c:3507
       do_mount fs/namespace.c:3847 [inline]
       __do_sys_mount fs/namespace.c:4055 [inline]
       __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4032
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&osb->nfs_sync_rwlock){.+.+}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3161 [inline]
       check_prevs_add kernel/locking/lockdep.c:3280 [inline]
       validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904
       __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5202
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825
       down_read+0xb1/0xa40 kernel/locking/rwsem.c:1524
       ocfs2_nfs_sync_lock+0x109/0x260 fs/ocfs2/dlmglue.c:2876
       ocfs2_delete_inode fs/ocfs2/inode.c:1030 [inline]
       ocfs2_evict_inode+0x3e5/0x4680 fs/ocfs2/inode.c:1216
       evict+0x4e8/0x9b0 fs/inode.c:723
       ocfs2_dentry_iput+0x232/0x380 fs/ocfs2/dcache.c:411
       __dentry_kill+0x20d/0x630 fs/dcache.c:615
       shrink_kill+0xa9/0x2c0 fs/dcache.c:1060
       shrink_dentry_list+0x2c0/0x5b0 fs/dcache.c:1087
       prune_dcache_sb+0x10f/0x180 fs/dcache.c:1168
       super_cache_scan+0x34f/0x4b0 fs/super.c:221
       do_shrink_slab+0x701/0x1160 mm/shrinker.c:435
       shrink_slab+0x1093/0x14d0 mm/shrinker.c:662
       shrink_one+0x43b/0x850 mm/vmscan.c:4818
       shrink_many mm/vmscan.c:4879 [inline]
       lru_gen_shrink_node mm/vmscan.c:4957 [inline]
       shrink_node+0x3799/0x3de0 mm/vmscan.c:5937
       kswapd_shrink_node mm/vmscan.c:6765 [inline]
       balance_pgdat mm/vmscan.c:6957 [inline]
       kswapd+0x1ca3/0x3700 mm/vmscan.c:7226
       kthread+0x2f0/0x390 kernel/kthread.c:389
       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:

Chain exists of:
  &osb->nfs_sync_rwlock --> &ocfs2_sysfile_lock_key[args->fi_sysfile_type]#2 --> fs_reclaim

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(fs_reclaim);
                               lock(&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#2);
                               lock(fs_reclaim);
  rlock(&osb->nfs_sync_rwlock);

 *** DEADLOCK ***

2 locks held by kswapd0/73:
 #0: ffffffff8ea37160 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6844 [inline]
 #0: ffffffff8ea37160 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xbf1/0x3700 mm/vmscan.c:7226
 #1: ffff88803d7880e0 (&type->s_umount_key#48){.+.+}-{3:3}, at: super_trylock_shared fs/super.c:562 [inline]
 #1: ffff88803d7880e0 (&type->s_umount_key#48){.+.+}-{3:3}, at: super_cache_scan+0x94/0x4b0 fs/super.c:196

stack backtrace:
CPU: 0 UID: 0 PID: 73 Comm: kswapd0 Not tainted 6.12.0-rc1-syzkaller-00330-gfc20a3e57247 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2206
 check_prev_add kernel/locking/lockdep.c:3161 [inline]
 check_prevs_add kernel/locking/lockdep.c:3280 [inline]
 validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904
 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5202
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825
 down_read+0xb1/0xa40 kernel/locking/rwsem.c:1524
 ocfs2_nfs_sync_lock+0x109/0x260 fs/ocfs2/dlmglue.c:2876
 ocfs2_delete_inode fs/ocfs2/inode.c:1030 [inline]
 ocfs2_evict_inode+0x3e5/0x4680 fs/ocfs2/inode.c:1216
 evict+0x4e8/0x9b0 fs/inode.c:723
 ocfs2_dentry_iput+0x232/0x380 fs/ocfs2/dcache.c:411
 __dentry_kill+0x20d/0x630 fs/dcache.c:615
 shrink_kill+0xa9/0x2c0 fs/dcache.c:1060
 shrink_dentry_list+0x2c0/0x5b0 fs/dcache.c:1087
 prune_dcache_sb+0x10f/0x180 fs/dcache.c:1168
 super_cache_scan+0x34f/0x4b0 fs/super.c:221
 do_shrink_slab+0x701/0x1160 mm/shrinker.c:435
 shrink_slab+0x1093/0x14d0 mm/shrinker.c:662
 shrink_one+0x43b/0x850 mm/vmscan.c:4818
 shrink_many mm/vmscan.c:4879 [inline]
 lru_gen_shrink_node mm/vmscan.c:4957 [inline]
 shrink_node+0x3799/0x3de0 mm/vmscan.c:5937
 kswapd_shrink_node mm/vmscan.c:6765 [inline]
 balance_pgdat mm/vmscan.c:6957 [inline]
 kswapd+0x1ca3/0x3700 mm/vmscan.c:7226
 kthread+0x2f0/0x390 kernel/kthread.c:389
 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>