======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.2.852/13750 is trying to acquire lock:
ffff88805dbcc5f8 (sb_pagefaults#2){.+.+}-{0:0}, at: do_page_mkwrite+0x150/0x310 mm/memory.c:3488
but task is already holding lock:
ffff88813ff74238 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_fop_readdir+0x267/0x870 fs/kernfs/dir.c:1893
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #4 (&root->kernfs_rwsem){++++}-{4:4}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
down_write+0x3a/0x50 kernel/locking/rwsem.c:1590
kernfs_add_one+0x41/0x520 fs/kernfs/dir.c:791
kernfs_create_dir_ns+0xde/0x130 fs/kernfs/dir.c:1093
sysfs_create_dir_ns+0x123/0x280 fs/sysfs/dir.c:59
create_dir lib/kobject.c:73 [inline]
kobject_add_internal+0x5a5/0xb50 lib/kobject.c:240
kobject_add_varg lib/kobject.c:374 [inline]
kobject_init_and_add+0x125/0x190 lib/kobject.c:457
btrfs_sysfs_add_qgroups+0x111/0x2b0 fs/btrfs/sysfs.c:2645
btrfs_quota_enable+0x25d/0x2920 fs/btrfs/qgroup.c:1022
btrfs_ioctl_quota_ctl+0x186/0x1c0 fs/btrfs/ioctl.c:3667
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xff/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #3 (&fs_info->qgroup_ioctl_lock){+.+.}-{4:4}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__mutex_lock_common kernel/locking/rtmutex_api.c:535 [inline]
mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:547
btrfs_quota_enable+0x29c/0x2920 fs/btrfs/qgroup.c:1051
btrfs_ioctl_quota_ctl+0x186/0x1c0 fs/btrfs/ioctl.c:3667
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xff/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #2 (btrfs_trans_num_extwriters){++++}-{0:0}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
join_transaction+0x1a4/0xca0 fs/btrfs/transaction.c:321
start_transaction+0x6b6/0x1620 fs/btrfs/transaction.c:705
btrfs_rebuild_free_space_tree+0xad/0x6d0 fs/btrfs/free-space-tree.c:1340
btrfs_start_pre_rw_mount+0x128f/0x1bf0 fs/btrfs/disk-io.c:3062
open_ctree+0x2b11/0x3d20 fs/btrfs/disk-io.c:3619
btrfs_fill_super fs/btrfs/super.c:987 [inline]
btrfs_get_tree_super fs/btrfs/super.c:1951 [inline]
btrfs_get_tree_subvol fs/btrfs/super.c:2094 [inline]
btrfs_get_tree+0x1061/0x1920 fs/btrfs/super.c:2128
vfs_get_tree+0x92/0x2b0 fs/super.c:1751
fc_mount fs/namespace.c:1208 [inline]
do_new_mount_fc fs/namespace.c:3651 [inline]
do_new_mount+0x302/0xa10 fs/namespace.c:3727
do_mount fs/namespace.c:4050 [inline]
__do_sys_mount fs/namespace.c:4238 [inline]
__se_sys_mount+0x313/0x410 fs/namespace.c:4215
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (btrfs_trans_num_writers){++++}-{0:0}:
reacquire_held_locks+0x127/0x1d0 kernel/locking/lockdep.c:5385
__lock_release kernel/locking/lockdep.c:5574 [inline]
lock_release+0x1b4/0x3e0 kernel/locking/lockdep.c:5889
percpu_up_read include/linux/percpu-rwsem.h:112 [inline]
__sb_end_write include/linux/fs.h:1911 [inline]
sb_end_intwrite+0x26/0x1c0 include/linux/fs.h:2028
__btrfs_end_transaction+0x248/0x640 fs/btrfs/transaction.c:1076
btrfs_dirty_inode+0x14c/0x190 fs/btrfs/inode.c:6284
inode_update_time fs/inode.c:2117 [inline]
__file_update_time fs/inode.c:2345 [inline]
file_update_time+0x34d/0x490 fs/inode.c:2375
btrfs_page_mkwrite+0x5dd/0x1a80 fs/btrfs/file.c:1915
do_page_mkwrite+0x150/0x310 mm/memory.c:3488
wp_page_shared mm/memory.c:3889 [inline]
do_wp_page+0x25c8/0x4930 mm/memory.c:4108
handle_pte_fault mm/memory.c:6193 [inline]
__handle_mm_fault mm/memory.c:6318 [inline]
handle_mm_fault+0x97c/0x3400 mm/memory.c:6487
do_user_addr_fault+0xa7c/0x1380 arch/x86/mm/fault.c:1336
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x82/0x100 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
-> #0 (sb_pagefaults#2){.+.+}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908
__lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline]
percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline]
__sb_start_write include/linux/fs.h:1916 [inline]
sb_start_pagefault include/linux/fs.h:2081 [inline]
btrfs_page_mkwrite+0x32c/0x1a80 fs/btrfs/file.c:1874
do_page_mkwrite+0x150/0x310 mm/memory.c:3488
wp_page_shared mm/memory.c:3889 [inline]
do_wp_page+0x25c8/0x4930 mm/memory.c:4108
handle_pte_fault mm/memory.c:6193 [inline]
__handle_mm_fault mm/memory.c:6318 [inline]
handle_mm_fault+0x97c/0x3400 mm/memory.c:6487
do_user_addr_fault+0x764/0x1380 arch/x86/mm/fault.c:1387
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x82/0x100 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
filldir64+0x2c1/0x690 fs/readdir.c:-1
dir_emit include/linux/fs.h:3986 [inline]
kernfs_fop_readdir+0x53a/0x870 fs/kernfs/dir.c:1910
iterate_dir+0x3a5/0x580 fs/readdir.c:108
__do_sys_getdents64 fs/readdir.c:410 [inline]
__se_sys_getdents64+0xe4/0x260 fs/readdir.c:396
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Chain exists of:
sb_pagefaults#2 --> &fs_info->qgroup_ioctl_lock --> &root->kernfs_rwsem
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
rlock(&root->kernfs_rwsem);
lock(&fs_info->qgroup_ioctl_lock);
lock(&root->kernfs_rwsem);
rlock(sb_pagefaults#2);
*** DEADLOCK ***
4 locks held by syz.2.852/13750:
#0: ffff888054109d28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x253/0x320 fs/file.c:1232
#1: ffff88805d4e2d78 (&type->i_mutex_dir_key#4){++++}-{4:4}, at: iterate_dir+0x29e/0x580 fs/readdir.c:101
#2: ffff88813ff74238 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_fop_readdir+0x267/0x870 fs/kernfs/dir.c:1893
#3: ffff888031af0dd0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock include/linux/mmap_lock.h:387 [inline]
#3: ffff888031af0dd0 (&mm->mmap_lock){++++}-{4:4}, at: get_mmap_lock_carefully mm/mmap_lock.c:368 [inline]
#3: ffff888031af0dd0 (&mm->mmap_lock){++++}-{4:4}, at: lock_mm_and_find_vma+0x32/0x300 mm/mmap_lock.c:428
stack backtrace:
CPU: 1 UID: 0 PID: 13750 Comm: syz.2.852 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
<TASK>
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043
check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908
__lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline]
percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline]
__sb_start_write include/linux/fs.h:1916 [inline]
sb_start_pagefault include/linux/fs.h:2081 [inline]
btrfs_page_mkwrite+0x32c/0x1a80 fs/btrfs/file.c:1874
do_page_mkwrite+0x150/0x310 mm/memory.c:3488
wp_page_shared mm/memory.c:3889 [inline]
do_wp_page+0x25c8/0x4930 mm/memory.c:4108
handle_pte_fault mm/memory.c:6193 [inline]
__handle_mm_fault mm/memory.c:6318 [inline]
handle_mm_fault+0x97c/0x3400 mm/memory.c:6487
do_user_addr_fault+0x764/0x1380 arch/x86/mm/fault.c:1387
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x82/0x100 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0010:filldir64+0x2c1/0x690 fs/readdir.c:379
Code: e8 48 8b 44 24 50 49 89 44 24 08 48 8b 4c 24 08 48 8b 44 24 58 48 89 01 48 8b 04 24 8b 54 24 14 49 bc 00 00 00 00 00 fc ff df <66> 89 41 10 80 e2 0f 88 51 12 49 63 ee c6 44 29 13 00 4c 8d 79 13
RSP: 0018:ffffc9000cc4fc58 EFLAGS: 00050283
RAX: 0000000000000020 RBX: ffffc9000cc4fe38 RCX: 0000200000001ff0
RDX: 0000000000000004 RSI: 0000200000001fd0 RDI: 0000200000002010
RBP: 00007ffffffff000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed10048ddb41 R12: dffffc0000000000
R13: ffffffff8b5658a0 R14: 0000000000000005 R15: 0000200000002010
dir_emit include/linux/fs.h:3986 [inline]
kernfs_fop_readdir+0x53a/0x870 fs/kernfs/dir.c:1910
iterate_dir+0x3a5/0x580 fs/readdir.c:108
__do_sys_getdents64 fs/readdir.c:410 [inline]
__se_sys_getdents64+0xe4/0x260 fs/readdir.c:396
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2b9929efc9
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:00007f2b974fe038 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00007f2b994f5fa0 RCX: 00007f2b9929efc9
RDX: 0000000000001000 RSI: 0000200000001f80 RDI: 0000000000000007
RBP: 00007f2b99321f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2b994f6038 R14: 00007f2b994f5fa0 R15: 00007ffeed5bd178
</TASK>
----------------
Code disassembly (best guess):
0: e8 48 8b 44 24 call 0x24448b4d
5: 50 push %rax
6: 49 89 44 24 08 mov %rax,0x8(%r12)
b: 48 8b 4c 24 08 mov 0x8(%rsp),%rcx
10: 48 8b 44 24 58 mov 0x58(%rsp),%rax
15: 48 89 01 mov %rax,(%rcx)
18: 48 8b 04 24 mov (%rsp),%rax
1c: 8b 54 24 14 mov 0x14(%rsp),%edx
20: 49 bc 00 00 00 00 00 movabs $0xdffffc0000000000,%r12
27: fc ff df
* 2a: 66 89 41 10 mov %ax,0x10(%rcx) <-- trapping instruction
2e: 80 e2 0f and $0xf,%dl
31: 88 51 12 mov %dl,0x12(%rcx)
34: 49 63 ee movslq %r14d,%rbp
37: c6 44 29 13 00 movb $0x0,0x13(%rcx,%rbp,1)
3c: 4c 8d 79 13 lea 0x13(%rcx),%r15