syzbot

======================================================
WARNING: possible circular locking dependency detected
6.7.0-rc2-syzkaller-00014-gc2d5304e6c64 #0 Not tainted
------------------------------------------------------
kswapd0/108 is trying to acquire lock:
ffff888045a30608 (sb_internal){.+.+}-{0:0}, at: evict+0x2ed/0x6b0 fs/inode.c:664

but task is already holding lock:
ffffffff8d11b9e0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x160/0x1a90 mm/vmscan.c:6716

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (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]
       __kmem_cache_alloc_node+0x51/0x310 mm/slub.c:3517
       __do_kmalloc_node mm/slab_common.c:1006 [inline]
       __kmalloc_node+0x4c/0x90 mm/slab_common.c:1014
       kmalloc_node include/linux/slab.h:620 [inline]
       kvmalloc_node+0x6f/0x1a0 mm/util.c:617
       kvmalloc include/linux/slab.h:738 [inline]
       ext4_xattr_inode_cache_find fs/ext4/xattr.c:1535 [inline]
       ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1577 [inline]
       ext4_xattr_set_entry+0x1c3f/0x3ce0 fs/ext4/xattr.c:1719
       ext4_xattr_block_set+0xcbf/0x3180 fs/ext4/xattr.c:2039
       ext4_xattr_set_handle+0xd70/0x1420 fs/ext4/xattr.c:2456
       ext4_xattr_set+0x149/0x370 fs/ext4/xattr.c:2558
       __vfs_setxattr+0x173/0x1d0 fs/xattr.c:201
       __vfs_setxattr_noperm+0x127/0x5e0 fs/xattr.c:235
       __vfs_setxattr_locked+0x17e/0x250 fs/xattr.c:296
       vfs_setxattr+0x146/0x350 fs/xattr.c:322
       do_setxattr+0x142/0x170 fs/xattr.c:630
       setxattr+0x159/0x170 fs/xattr.c:653
       __do_sys_fsetxattr fs/xattr.c:709 [inline]
       __se_sys_fsetxattr fs/xattr.c:698 [inline]
       __ia32_sys_fsetxattr+0x25e/0x310 fs/xattr.c:698
       do_syscall_32_irqs_on arch/x86/entry/common.c:164 [inline]
       __do_fast_syscall_32+0x62/0xe0 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

-> #2 (&ei->xattr_sem){++++}-{3:3}:
       down_write+0x3a/0x50 kernel/locking/rwsem.c:1579
       ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline]
       ext4_xattr_set_handle+0x159/0x1420 fs/ext4/xattr.c:2371
       __ext4_set_acl+0x362/0x5d0 fs/ext4/acl.c:217
       ext4_set_acl+0x2a0/0x5a0 fs/ext4/acl.c:259
       set_posix_acl+0x259/0x320 fs/posix_acl.c:956
       vfs_remove_acl+0x2cd/0x620 fs/posix_acl.c:1243
       ovl_do_remove_acl fs/overlayfs/overlayfs.h:348 [inline]
       ovl_workdir_create+0x4a1/0x820 fs/overlayfs/super.c:348
       ovl_make_workdir fs/overlayfs/super.c:662 [inline]
       ovl_get_workdir fs/overlayfs/super.c:820 [inline]
       ovl_fill_super+0xe57/0x6560 fs/overlayfs/super.c:1376
       vfs_get_super fs/super.c:1338 [inline]
       get_tree_nodev+0xd6/0x180 fs/super.c:1357
       vfs_get_tree+0x8c/0x370 fs/super.c:1771
       do_new_mount fs/namespace.c:3337 [inline]
       path_mount+0x1492/0x1ed0 fs/namespace.c:3664
       do_mount fs/namespace.c:3677 [inline]
       __do_sys_mount fs/namespace.c:3886 [inline]
       __se_sys_mount fs/namespace.c:3863 [inline]
       __ia32_sys_mount+0x291/0x310 fs/namespace.c:3863
       do_syscall_32_irqs_on arch/x86/entry/common.c:164 [inline]
       __do_fast_syscall_32+0x62/0xe0 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 (jbd2_handle){++++}-{0:0}:
       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_sample_last_mounted fs/ext4/file.c:835 [inline]
       ext4_file_open+0x632/0xc80 fs/ext4/file.c:864
       do_dentry_open+0x8d6/0x18c0 fs/open.c:948
       do_open fs/namei.c:3622 [inline]
       path_openat+0x1e5a/0x2c50 fs/namei.c:3779
       do_filp_open+0x1de/0x430 fs/namei.c:3809
       do_sys_openat2+0x176/0x1e0 fs/open.c:1440
       do_sys_open fs/open.c:1455 [inline]
       __do_sys_openat fs/open.c:1471 [inline]
       __se_sys_openat fs/open.c:1466 [inline]
       __x64_sys_openat+0x175/0x210 fs/open.c:1466
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82
       entry_SYSCALL_64_after_hwframe+0x63/0x6b

-> #0 (sb_internal){.+.+}-{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+0x2464/0x3b10 kernel/locking/lockdep.c:5136
       lock_acquire kernel/locking/lockdep.c:5753 [inline]
       lock_acquire+0x1ae/0x520 kernel/locking/lockdep.c:5718
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1635 [inline]
       sb_start_intwrite include/linux/fs.h:1757 [inline]
       ext4_evict_inode+0xe5b/0x1a40 fs/ext4/inode.c:212
       evict+0x2ed/0x6b0 fs/inode.c:664
       iput_final fs/inode.c:1775 [inline]
       iput.part.0+0x560/0x7b0 fs/inode.c:1801
       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+0x11e/0x4a0 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+0x9d2/0x1a90 mm/vmscan.c:6828
       kswapd+0x5be/0xbf0 mm/vmscan.c:7088
       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:
  sb_internal --> &ei->xattr_sem --> fs_reclaim

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(fs_reclaim);
                               lock(&ei->xattr_sem);
                               lock(fs_reclaim);
  rlock(sb_internal);

 *** DEADLOCK ***

2 locks held by kswapd0/108:
 #0: ffffffff8d11b9e0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x160/0x1a90 mm/vmscan.c:6716
 #1: ffff888045a300e0 (&type->s_umount_key#32){++++}-{3:3}, at: super_trylock_shared fs/super.c:610 [inline]
 #1: ffff888045a300e0 (&type->s_umount_key#32){++++}-{3:3}, at: super_cache_scan+0x96/0x540 fs/super.c:203

stack backtrace:
CPU: 0 PID: 108 Comm: kswapd0 Not tainted 6.7.0-rc2-syzkaller-00014-gc2d5304e6c64 #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+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:3868 [inline]
 __lock_acquire+0x2464/0x3b10 kernel/locking/lockdep.c:5136
 lock_acquire kernel/locking/lockdep.c:5753 [inline]
 lock_acquire+0x1ae/0x520 kernel/locking/lockdep.c:5718
 percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
 __sb_start_write include/linux/fs.h:1635 [inline]
 sb_start_intwrite include/linux/fs.h:1757 [inline]
 ext4_evict_inode+0xe5b/0x1a40 fs/ext4/inode.c:212
 evict+0x2ed/0x6b0 fs/inode.c:664
 iput_final fs/inode.c:1775 [inline]
 iput.part.0+0x560/0x7b0 fs/inode.c:1801
 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+0x11e/0x4a0 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+0x9d2/0x1a90 mm/vmscan.c:6828
 kswapd+0x5be/0xbf0 mm/vmscan.c:7088
 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
 </TASK>