syzbot

======================================================
WARNING: possible circular locking dependency detected
6.11.0-rc7-syzkaller #0 Not tainted
------------------------------------------------------
syz.4.1455/16784 is trying to acquire lock:
ffffffff8ea2fde0 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:334 [inline]
ffffffff8ea2fde0 (fs_reclaim){+.+.}-{0:0}, at: slab_pre_alloc_hook mm/slub.c:3943 [inline]
ffffffff8ea2fde0 (fs_reclaim){+.+.}-{0:0}, at: slab_alloc_node mm/slub.c:4021 [inline]
ffffffff8ea2fde0 (fs_reclaim){+.+.}-{0:0}, at: __do_kmalloc_node mm/slub.c:4161 [inline]
ffffffff8ea2fde0 (fs_reclaim){+.+.}-{0:0}, at: __kmalloc_noprof+0xa9/0x400 mm/slub.c:4174

but task is already holding lock:
ffff88805f365e18 (&xfs_nondir_ilock_class#3){++++}-{3:3}, at: xfs_ilock_attr_map_shared+0x8c/0xc0 fs/xfs/xfs_inode.c:84

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&xfs_nondir_ilock_class#3){++++}-{3:3}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
       down_read_nested+0xb5/0xa50 kernel/locking/rwsem.c:1651
       xfs_can_free_eofblocks+0x5f1/0x8d0 fs/xfs/xfs_bmap_util.c:550
       xfs_inode_mark_reclaimable+0x1bb/0xf60 fs/xfs/xfs_icache.c:2148
       destroy_inode fs/inode.c:313 [inline]
       evict+0x80b/0x950 fs/inode.c:729
       dispose_list fs/inode.c:747 [inline]
       prune_icache_sb+0x239/0x2f0 fs/inode.c:932
       super_cache_scan+0x38c/0x4b0 fs/super.c:223
       do_shrink_slab+0x703/0x1160 mm/shrinker.c:435
       shrink_slab_memcg mm/shrinker.c:548 [inline]
       shrink_slab+0x878/0x14d0 mm/shrinker.c:626
       shrink_one+0x43b/0x850 mm/vmscan.c:4795
       shrink_many mm/vmscan.c:4856 [inline]
       lru_gen_shrink_node mm/vmscan.c:4934 [inline]
       shrink_node+0x3799/0x3de0 mm/vmscan.c:5914
       kswapd_shrink_node mm/vmscan.c:6742 [inline]
       balance_pgdat mm/vmscan.c:6934 [inline]
       kswapd+0x1cbc/0x3720 mm/vmscan.c:7203
       kthread+0x2f2/0x390 kernel/kthread.c:389
       ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #0 (fs_reclaim){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3133 [inline]
       check_prevs_add kernel/locking/lockdep.c:3252 [inline]
       validate_chain+0x18e0/0x5900 kernel/locking/lockdep.c:3868
       __lock_acquire+0x137a/0x2040 kernel/locking/lockdep.c:5142
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
       __fs_reclaim_acquire mm/page_alloc.c:3825 [inline]
       fs_reclaim_acquire+0x88/0x140 mm/page_alloc.c:3839
       might_alloc include/linux/sched/mm.h:334 [inline]
       slab_pre_alloc_hook mm/slub.c:3943 [inline]
       slab_alloc_node mm/slub.c:4021 [inline]
       __do_kmalloc_node mm/slub.c:4161 [inline]
       __kmalloc_noprof+0xa9/0x400 mm/slub.c:4174
       kmalloc_noprof include/linux/slab.h:685 [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
       ovl_copy_xattr+0x1a2/0xb60 fs/overlayfs/copy_up.c:98
       ovl_copy_up_metadata+0x24f/0xda0 fs/overlayfs/copy_up.c:650
       ovl_copy_up_tmpfile fs/overlayfs/copy_up.c:870 [inline]
       ovl_do_copy_up fs/overlayfs/copy_up.c:976 [inline]
       ovl_copy_up_one fs/overlayfs/copy_up.c:1168 [inline]
       ovl_copy_up_flags+0x1eba/0x4470 fs/overlayfs/copy_up.c:1223
       ovl_open+0x142/0x2a0 fs/overlayfs/file.c:154
       do_dentry_open+0x972/0x1440 fs/open.c:959
       vfs_open+0x3e/0x330 fs/open.c:1089
       do_open fs/namei.c:3727 [inline]
       path_openat+0x2b3e/0x3470 fs/namei.c:3886
       do_filp_open+0x235/0x490 fs/namei.c:3913
       do_sys_openat2+0x13e/0x1d0 fs/open.c:1416
       do_sys_open fs/open.c:1431 [inline]
       __do_sys_creat fs/open.c:1507 [inline]
       __se_sys_creat fs/open.c:1501 [inline]
       __x64_sys_creat+0x123/0x170 fs/open.c:1501
       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

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rlock(&xfs_nondir_ilock_class#3);
                               lock(fs_reclaim);
                               lock(&xfs_nondir_ilock_class#3);
  lock(fs_reclaim);

 *** DEADLOCK ***

4 locks held by syz.4.1455/16784:
 #0: ffff8880438c0420 (sb_writers#18){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:515
 #1: ffff88805f2ed048 (&ovl_i_lock_key[depth]){+.+.}-{3:3}, at: ovl_inode_lock_interruptible fs/overlayfs/overlayfs.h:657 [inline]
 #1: ffff88805f2ed048 (&ovl_i_lock_key[depth]){+.+.}-{3:3}, at: ovl_copy_up_start+0x53/0x310 fs/overlayfs/util.c:719
 #2: ffff888051282420 (sb_writers#32){.+.+}-{0:0}, at: ovl_copy_up_tmpfile fs/overlayfs/copy_up.c:868 [inline]
 #2: ffff888051282420 (sb_writers#32){.+.+}-{0:0}, at: ovl_do_copy_up fs/overlayfs/copy_up.c:976 [inline]
 #2: ffff888051282420 (sb_writers#32){.+.+}-{0:0}, at: ovl_copy_up_one fs/overlayfs/copy_up.c:1168 [inline]
 #2: ffff888051282420 (sb_writers#32){.+.+}-{0:0}, at: ovl_copy_up_flags+0x1ead/0x4470 fs/overlayfs/copy_up.c:1223
 #3: ffff88805f365e18 (&xfs_nondir_ilock_class#3){++++}-{3:3}, at: xfs_ilock_attr_map_shared+0x8c/0xc0 fs/xfs/xfs_inode.c:84

stack backtrace:
CPU: 1 UID: 0 PID: 16784 Comm: syz.4.1455 Not tainted 6.11.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:93 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2186
 check_prev_add kernel/locking/lockdep.c:3133 [inline]
 check_prevs_add kernel/locking/lockdep.c:3252 [inline]
 validate_chain+0x18e0/0x5900 kernel/locking/lockdep.c:3868
 __lock_acquire+0x137a/0x2040 kernel/locking/lockdep.c:5142
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
 __fs_reclaim_acquire mm/page_alloc.c:3825 [inline]
 fs_reclaim_acquire+0x88/0x140 mm/page_alloc.c:3839
 might_alloc include/linux/sched/mm.h:334 [inline]
 slab_pre_alloc_hook mm/slub.c:3943 [inline]
 slab_alloc_node mm/slub.c:4021 [inline]
 __do_kmalloc_node mm/slub.c:4161 [inline]
 __kmalloc_noprof+0xa9/0x400 mm/slub.c:4174
 kmalloc_noprof include/linux/slab.h:685 [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
 ovl_copy_xattr+0x1a2/0xb60 fs/overlayfs/copy_up.c:98
 ovl_copy_up_metadata+0x24f/0xda0 fs/overlayfs/copy_up.c:650
 ovl_copy_up_tmpfile fs/overlayfs/copy_up.c:870 [inline]
 ovl_do_copy_up fs/overlayfs/copy_up.c:976 [inline]
 ovl_copy_up_one fs/overlayfs/copy_up.c:1168 [inline]
 ovl_copy_up_flags+0x1eba/0x4470 fs/overlayfs/copy_up.c:1223
 ovl_open+0x142/0x2a0 fs/overlayfs/file.c:154
 do_dentry_open+0x972/0x1440 fs/open.c:959
 vfs_open+0x3e/0x330 fs/open.c:1089
 do_open fs/namei.c:3727 [inline]
 path_openat+0x2b3e/0x3470 fs/namei.c:3886
 do_filp_open+0x235/0x490 fs/namei.c:3913
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1416
 do_sys_open fs/open.c:1431 [inline]
 __do_sys_creat fs/open.c:1507 [inline]
 __se_sys_creat fs/open.c:1501 [inline]
 __x64_sys_creat+0x123/0x170 fs/open.c:1501
 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
RIP: 0033:0x7f02ec97cef9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f02ed69c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007f02ecb35f80 RCX: 00007f02ec97cef9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000200000c0
RBP: 00007f02ec9ef046 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f02ecb35f80 R15: 00007ffd637bdb68
 </TASK>