syzbot

XFS (loop0): Ending clean mount
XFS (loop0): Quotacheck needed: Please wait.
XFS (loop0): Quotacheck: Done.
======================================================
WARNING: possible circular locking dependency detected
6.11.0-rc7-syzkaller-00151-gd42f7708e27c #0 Not tainted
------------------------------------------------------
syz.0.129/5677 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:
ffff88803c385098 (&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_write_nested+0xa2/0x220 kernel/locking/rwsem.c:1695
       xfs_reclaim_inode fs/xfs/xfs_icache.c:944 [inline]
       xfs_icwalk_process_inode fs/xfs/xfs_icache.c:1630 [inline]
       xfs_icwalk_ag+0x120e/0x1ad0 fs/xfs/xfs_icache.c:1712
       xfs_icwalk fs/xfs/xfs_icache.c:1761 [inline]
       xfs_reclaim_inodes_nr+0x2d4/0x3e0 fs/xfs/xfs_icache.c:1010
       super_cache_scan+0x40f/0x4b0 fs/super.c:227
       do_shrink_slab+0x701/0x1160 mm/shrinker.c:435
       shrink_slab+0x1093/0x14d0 mm/shrinker.c:662
       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+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

-> #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
       vfs_listxattr fs/xattr.c:493 [inline]
       listxattr+0x107/0x290 fs/xattr.c:841
       path_listxattr fs/xattr.c:865 [inline]
       __do_sys_listxattr fs/xattr.c:877 [inline]
       __se_sys_listxattr fs/xattr.c:874 [inline]
       __x64_sys_listxattr+0x173/0x230 fs/xattr.c:874
       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 ***

1 lock held by syz.0.129/5677:
 #0: ffff88803c385098 (&xfs_nondir_ilock_class#3){++++}-{3:3}, at: xfs_ilock_attr_map_shared+0x8c/0xc0 fs/xfs/xfs_inode.c:84

stack backtrace:
CPU: 0 UID: 0 PID: 5677 Comm: syz.0.129 Not tainted 6.11.0-rc7-syzkaller-00151-gd42f7708e27c #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
 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
 vfs_listxattr fs/xattr.c:493 [inline]
 listxattr+0x107/0x290 fs/xattr.c:841
 path_listxattr fs/xattr.c:865 [inline]
 __do_sys_listxattr fs/xattr.c:877 [inline]
 __se_sys_listxattr fs/xattr.c:874 [inline]
 __x64_sys_listxattr+0x173/0x230 fs/xattr.c:874
 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: 0033:0x7f3ffe77def9
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:00007f3fff665038 EFLAGS: 00000246 ORIG_RAX: 00000000000000c2
RAX: ffffffffffffffda RBX: 00007f3ffe935f80 RCX: 00007f3ffe77def9
RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000000020000a00
RBP: 00007f3ffe7f0b76 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f3ffe935f80 R15: 00007ffe570fb968
 </TASK>