syzbot

======================================================
WARNING: possible circular locking dependency detected
6.11.0-syzkaller-08068-g1ec6d097897a #0 Not tainted
------------------------------------------------------
kswapd0/73 is trying to acquire lock:
ffff88803de98610 (sb_internal#2){.+.+}-{0:0}, at: xfs_fs_dirty_inode+0x158/0x250 fs/xfs/xfs_super.c:691

but task is already holding lock:
ffffffff8ea36bc0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6844 [inline]
ffffffff8ea36bc0 (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:

-> #2 (fs_reclaim){+.+.}-{0:0}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
       __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:4037 [inline]
       slab_alloc_node mm/slub.c:4115 [inline]
       __do_kmalloc_node mm/slub.c:4264 [inline]
       __kmalloc_noprof+0xa9/0x400 mm/slub.c:4277
       kmalloc_noprof include/linux/slab.h:882 [inline]
       xfs_attr_shortform_list+0x753/0x1900 fs/xfs/xfs_attr_list.c:117
       xfs_attr_list+0x1d0/0x270 fs/xfs/xfs_attr_list.c:595
       xfs_vn_listxattr+0x1d2/0x2c0 fs/xfs/xfs_xattr.c:341
       vfs_listxattr fs/xattr.c:493 [inline]
       listxattr+0x107/0x290 fs/xattr.c:841
       path_listxattr fs/xattr.c:865 [inline]
       __do_sys_llistxattr fs/xattr.c:883 [inline]
       __se_sys_llistxattr fs/xattr.c:880 [inline]
       __x64_sys_llistxattr+0x170/0x230 fs/xattr.c:880
       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 (&xfs_dir_ilock_class){++++}-{3:3}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
       down_write_nested+0xa2/0x220 kernel/locking/rwsem.c:1695
       xfs_trans_alloc_inode+0x1e0/0x5d0 fs/xfs/xfs_trans.c:1083
       xfs_attr_add_fork+0x1b5/0x380 fs/xfs/libxfs/xfs_attr.c:960
       xfs_attr_set+0x73c/0x1420 fs/xfs/libxfs/xfs_attr.c:1023
       xfs_xattr_set+0x1ff/0x350 fs/xfs/xfs_xattr.c:187
       __vfs_setxattr+0x468/0x4a0 fs/xattr.c:200
       __vfs_setxattr_noperm+0x12e/0x660 fs/xattr.c:234
       vfs_setxattr+0x221/0x430 fs/xattr.c:321
       do_setxattr fs/xattr.c:629 [inline]
       path_setxattr+0x37e/0x4d0 fs/xattr.c:658
       __do_sys_lsetxattr fs/xattr.c:683 [inline]
       __se_sys_lsetxattr fs/xattr.c:679 [inline]
       __x64_sys_lsetxattr+0xb8/0xd0 fs/xattr.c:679
       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 (sb_internal#2){.+.+}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3158 [inline]
       check_prevs_add kernel/locking/lockdep.c:3277 [inline]
       validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3901
       __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5199
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1715 [inline]
       sb_start_intwrite include/linux/fs.h:1898 [inline]
       xfs_trans_alloc+0xe5/0x830 fs/xfs/xfs_trans.c:264
       xfs_fs_dirty_inode+0x158/0x250 fs/xfs/xfs_super.c:691
       __mark_inode_dirty+0x2ee/0xe90 fs/fs-writeback.c:2493
       mark_inode_dirty_sync include/linux/fs.h:2478 [inline]
       iput+0x1f1/0xa50 fs/inode.c:1906
       __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:
  sb_internal#2 --> &xfs_dir_ilock_class --> fs_reclaim

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(fs_reclaim);
                               lock(&xfs_dir_ilock_class);
                               lock(fs_reclaim);
  rlock(sb_internal#2);

 *** DEADLOCK ***

2 locks held by kswapd0/73:
 #0: ffffffff8ea36bc0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6844 [inline]
 #0: ffffffff8ea36bc0 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xbf1/0x3700 mm/vmscan.c:7226
 #1: ffff88803de980e0 (&type->s_umount_key#47){.+.+}-{3:3}, at: super_trylock_shared fs/super.c:562 [inline]
 #1: ffff88803de980e0 (&type->s_umount_key#47){.+.+}-{3:3}, at: super_cache_scan+0x94/0x4b0 fs/super.c:196

stack backtrace:
CPU: 0 UID: 0 PID: 73 Comm: kswapd0 Not tainted 6.11.0-syzkaller-08068-g1ec6d097897a #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:93 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119
 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2203
 check_prev_add kernel/locking/lockdep.c:3158 [inline]
 check_prevs_add kernel/locking/lockdep.c:3277 [inline]
 validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3901
 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5199
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
 percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
 __sb_start_write include/linux/fs.h:1715 [inline]
 sb_start_intwrite include/linux/fs.h:1898 [inline]
 xfs_trans_alloc+0xe5/0x830 fs/xfs/xfs_trans.c:264
 xfs_fs_dirty_inode+0x158/0x250 fs/xfs/xfs_super.c:691
 __mark_inode_dirty+0x2ee/0xe90 fs/fs-writeback.c:2493
 mark_inode_dirty_sync include/linux/fs.h:2478 [inline]
 iput+0x1f1/0xa50 fs/inode.c:1906
 __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