======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G             L     
------------------------------------------------------
syz.0.986/8785 is trying to acquire lock:
ffff88804f0029d8 (&c->xattr_sem){++++}-{4:4}, at: jffs2_xattr_delete_inode+0x83/0x130 fs/jffs2/xattr.c:605

but task is already holding lock:
ffffffff8efc9860 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4448 [inline]
ffffffff8efc9860 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4478 [inline]
ffffffff8efc9860 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath mm/page_alloc.c:4939 [inline]
ffffffff8efc9860 (fs_reclaim){+.+.}-{0:0}, at: __alloc_frozen_pages_noprof+0xf35/0x3300 mm/page_alloc.c:5449

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (fs_reclaim){+.+.}-{0:0}:
       lock_acquire kernel/locking/lockdep.c:5942 [inline]
       lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899
       __fs_reclaim_acquire mm/page_alloc.c:4375 [inline]
       fs_reclaim_acquire+0xc4/0x100 mm/page_alloc.c:4389
       might_alloc include/linux/sched/mm.h:316 [inline]
       slab_pre_alloc_hook mm/slub.c:4636 [inline]
       slab_alloc_node mm/slub.c:4974 [inline]
       kmem_cache_alloc_noprof+0x63/0x6a0 mm/slub.c:5010
       jffs2_alloc_xattr_datum+0x1c/0xe0 fs/jffs2/malloc.c:264
       create_xattr_datum fs/jffs2/xattr.c:363 [inline]
       do_jffs2_setxattr+0x6f0/0x1610 fs/jffs2/xattr.c:1175
       __vfs_setxattr+0x175/0x1e0 fs/xattr.c:223
       __vfs_setxattr_noperm+0x127/0x660 fs/xattr.c:257
       __vfs_setxattr_locked+0x127/0x2b0 fs/xattr.c:318
       vfs_setxattr+0x14a/0x390 fs/xattr.c:344
       ovl_do_setxattr fs/overlayfs/overlayfs.h:324 [inline]
       ovl_setxattr fs/overlayfs/overlayfs.h:336 [inline]
       ovl_make_workdir fs/overlayfs/super.c:724 [inline]
       ovl_get_workdir fs/overlayfs/super.c:836 [inline]
       ovl_fill_super_creds fs/overlayfs/super.c:1449 [inline]
       ovl_fill_super+0x1320/0x5ea0 fs/overlayfs/super.c:1561
       vfs_get_super fs/super.c:1405 [inline]
       get_tree_nodev+0xdd/0x190 fs/super.c:1424
       vfs_get_tree+0x92/0x320 fs/super.c:1947
       fc_mount fs/namespace.c:1198 [inline]
       do_new_mount_fc fs/namespace.c:3772 [inline]
       do_new_mount fs/namespace.c:3848 [inline]
       path_mount+0x7d0/0x24c0 fs/namespace.c:4168
       do_mount fs/namespace.c:4181 [inline]
       __do_sys_mount fs/namespace.c:4397 [inline]
       __se_sys_mount fs/namespace.c:4374 [inline]
       __ia32_sys_mount+0x292/0x310 fs/namespace.c:4374
       do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:79 [inline]
       __do_fast_syscall_32+0x13a/0x8b0 arch/x86/entry/syscall_32.c:291
       do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:316
       entry_SYSENTER_compat_after_hwframe+0x84/0x8e

-> #0 (&c->xattr_sem){++++}-{4:4}:
       check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3209
       check_prevs_add kernel/locking/lockdep.c:3328 [inline]
       validate_chain kernel/locking/lockdep.c:3952 [inline]
       __lock_acquire+0x1528/0x1f40 kernel/locking/lockdep.c:5288
       lock_acquire kernel/locking/lockdep.c:5942 [inline]
       lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899
       down_write+0x8b/0x1f0 kernel/locking/rwsem.c:1631
       jffs2_xattr_delete_inode+0x83/0x130 fs/jffs2/xattr.c:605
       jffs2_do_clear_inode+0x50/0x470 fs/jffs2/readinode.c:1418
       evict+0x3c2/0xad0 fs/inode.c:822
       iput_final fs/inode.c:2015 [inline]
       iput.part.0+0x989/0x1050 fs/inode.c:2064
       iput+0x35/0x40 fs/inode.c:2030
       dentry_unlink_inode+0x284/0x470 fs/dcache.c:479
       dentry_kill+0x25d/0xc20 fs/dcache.c:826
       finish_dput fs/dcache.c:1001 [inline]
       dput.part.0+0xd7/0x240 fs/dcache.c:1042
       dput+0x1f/0x30 fs/dcache.c:1037
       ovl_destroy_inode+0x3e/0x190 fs/overlayfs/super.c:217
       destroy_inode+0xcb/0x1c0 fs/inode.c:387
       evict+0x599/0xad0 fs/inode.c:846
       iput_final fs/inode.c:2015 [inline]
       iput.part.0+0x989/0x1050 fs/inode.c:2064
       iput+0x35/0x40 fs/inode.c:2030
       dentry_unlink_inode+0x284/0x470 fs/dcache.c:479
       dentry_kill+0x25d/0xc20 fs/dcache.c:826
       shrink_kill fs/dcache.c:1275 [inline]
       shrink_dentry_list+0x1e8/0x310 fs/dcache.c:1292
       prune_dcache_sb+0xea/0x150 fs/dcache.c:1374
       super_cache_scan+0x361/0x5c0 fs/super.c:238
       do_shrink_slab+0x416/0x1200 mm/shrinker.c:443
       shrink_slab_memcg mm/shrinker.c:560 [inline]
       shrink_slab+0xa82/0x12e0 mm/shrinker.c:638
       shrink_one+0x398/0x850 mm/vmscan.c:5119
       shrink_many mm/vmscan.c:5180 [inline]
       lru_gen_shrink_node mm/vmscan.c:5258 [inline]
       shrink_node+0x2b20/0x4320 mm/vmscan.c:6247
       shrink_zones mm/vmscan.c:6503 [inline]
       do_try_to_free_pages+0x33e/0x16d0 mm/vmscan.c:6565
       try_to_free_pages+0x2a0/0x740 mm/vmscan.c:6804
       __perform_reclaim mm/page_alloc.c:4451 [inline]
       __alloc_pages_direct_reclaim mm/page_alloc.c:4478 [inline]
       __alloc_pages_slowpath mm/page_alloc.c:4939 [inline]
       __alloc_frozen_pages_noprof+0xf8a/0x3300 mm/page_alloc.c:5449
       alloc_pages_mpol+0x201/0x550 mm/mempolicy.c:2486
       folio_alloc_mpol_noprof+0x36/0x260 mm/mempolicy.c:2505
       alloc_migration_target_by_mpol+0x2c1/0x650 mm/mempolicy.c:1466
       migrate_folio_unmap mm/migrate.c:1225 [inline]
       migrate_pages_batch+0x5c4/0x4680 mm/migrate.c:1918
       migrate_pages_sync+0x12c/0x880 mm/migrate.c:2035
       migrate_pages+0x1a83/0x2850 mm/migrate.c:2144
       do_mbind+0x5a4/0xfd0 mm/mempolicy.c:1617
       kernel_mbind+0x1b7/0x200 mm/mempolicy.c:1760
       do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:79 [inline]
       __do_fast_syscall_32+0x13a/0x8b0 arch/x86/entry/syscall_32.c:291
       do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:316
       entry_SYSENTER_compat_after_hwframe+0x84/0x8e

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(fs_reclaim);
                               lock(&c->xattr_sem);
                               lock(fs_reclaim);
  lock(&c->xattr_sem);

 *** DEADLOCK ***

locks held by syz.0.986/8785: 2, last CPU#3:
 #0: ffffffff8efc9860 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim mm/page_alloc.c:4448 [inline]
 #0: ffffffff8efc9860 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_direct_reclaim mm/page_alloc.c:4478 [inline]
 #0: ffffffff8efc9860 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath mm/page_alloc.c:4939 [inline]
 #0: ffffffff8efc9860 (fs_reclaim){+.+.}-{0:0}, at: __alloc_frozen_pages_noprof+0xf35/0x3300 mm/page_alloc.c:5449
 #1: ffff88804c56a0e8 (&type->s_umount_key#61){++++}-{4:4}, at: super_trylock_shared fs/super.c:688 [inline]
 #1: ffff88804c56a0e8 (&type->s_umount_key#61){++++}-{4:4}, at: super_cache_scan+0x9b/0x5c0 fs/super.c:213

stack backtrace:
CPU: 3 UID: 0 PID: 8785 Comm: syz.0.986 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_circular_bug.cold+0x178/0x1be kernel/locking/lockdep.c:2087
 check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2219
 check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3209
 check_prevs_add kernel/locking/lockdep.c:3328 [inline]
 validate_chain kernel/locking/lockdep.c:3952 [inline]
 __lock_acquire+0x1528/0x1f40 kernel/locking/lockdep.c:5288
 lock_acquire kernel/locking/lockdep.c:5942 [inline]
 lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899
 down_write+0x8b/0x1f0 kernel/locking/rwsem.c:1631
 jffs2_xattr_delete_inode+0x83/0x130 fs/jffs2/xattr.c:605
 jffs2_do_clear_inode+0x50/0x470 fs/jffs2/readinode.c:1418
 evict+0x3c2/0xad0 fs/inode.c:822
 iput_final fs/inode.c:2015 [inline]
 iput.part.0+0x989/0x1050 fs/inode.c:2064
 iput+0x35/0x40 fs/inode.c:2030
 dentry_unlink_inode+0x284/0x470 fs/dcache.c:479
 dentry_kill+0x25d/0xc20 fs/dcache.c:826
 finish_dput fs/dcache.c:1001 [inline]
 dput.part.0+0xd7/0x240 fs/dcache.c:1042
 dput+0x1f/0x30 fs/dcache.c:1037
 ovl_destroy_inode+0x3e/0x190 fs/overlayfs/super.c:217
 destroy_inode+0xcb/0x1c0 fs/inode.c:387
 evict+0x599/0xad0 fs/inode.c:846
 iput_final fs/inode.c:2015 [inline]
 iput.part.0+0x989/0x1050 fs/inode.c:2064
 iput+0x35/0x40 fs/inode.c:2030
 dentry_unlink_inode+0x284/0x470 fs/dcache.c:479
 dentry_kill+0x25d/0xc20 fs/dcache.c:826
 shrink_kill fs/dcache.c:1275 [inline]
 shrink_dentry_list+0x1e8/0x310 fs/dcache.c:1292
 prune_dcache_sb+0xea/0x150 fs/dcache.c:1374
 super_cache_scan+0x361/0x5c0 fs/super.c:238
 do_shrink_slab+0x416/0x1200 mm/shrinker.c:443
 shrink_slab_memcg mm/shrinker.c:560 [inline]
 shrink_slab+0xa82/0x12e0 mm/shrinker.c:638
 shrink_one+0x398/0x850 mm/vmscan.c:5119
 shrink_many mm/vmscan.c:5180 [inline]
 lru_gen_shrink_node mm/vmscan.c:5258 [inline]
 shrink_node+0x2b20/0x4320 mm/vmscan.c:6247
 shrink_zones mm/vmscan.c:6503 [inline]
 do_try_to_free_pages+0x33e/0x16d0 mm/vmscan.c:6565
 try_to_free_pages+0x2a0/0x740 mm/vmscan.c:6804
 __perform_reclaim mm/page_alloc.c:4451 [inline]
 __alloc_pages_direct_reclaim mm/page_alloc.c:4478 [inline]
 __alloc_pages_slowpath mm/page_alloc.c:4939 [inline]
 __alloc_frozen_pages_noprof+0xf8a/0x3300 mm/page_alloc.c:5449
 alloc_pages_mpol+0x201/0x550 mm/mempolicy.c:2486
 folio_alloc_mpol_noprof+0x36/0x260 mm/mempolicy.c:2505
 alloc_migration_target_by_mpol+0x2c1/0x650 mm/mempolicy.c:1466
 migrate_folio_unmap mm/migrate.c:1225 [inline]
 migrate_pages_batch+0x5c4/0x4680 mm/migrate.c:1918
 migrate_pages_sync+0x12c/0x880 mm/migrate.c:2035
 migrate_pages+0x1a83/0x2850 mm/migrate.c:2144
 do_mbind+0x5a4/0xfd0 mm/mempolicy.c:1617
 kernel_mbind+0x1b7/0x200 mm/mempolicy.c:1760
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:79 [inline]
 __do_fast_syscall_32+0x13a/0x8b0 arch/x86/entry/syscall_32.c:291
 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:316
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf700efec
Code: Unable to access opcode bytes at 0xf700efc2.
RSP: 002b:00000000f53fd50c EFLAGS: 00000292 ORIG_RAX: 0000000000000112
RAX: ffffffffffffffda RBX: 0000000080000000 RCX: 0000000000600000
RDX: 0000000000000002 RSI: 0000000080000000 RDI: 0000000000000008
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>