====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.4.316/8295 is trying to acquire lock: ffff88806701e2e8 (&fs_info->qgroup_ioctl_lock){+.+.}-{4:4}, at: btrfs_quota_enable+0x2c6/0x2850 fs/btrfs/qgroup.c:1063 but task is already holding lock: ffff88806701f140 (btrfs_trans_num_extwriters){++++}-{0:0}, at: join_transaction+0x164/0xc90 fs/btrfs/transaction.c:322 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (btrfs_trans_num_extwriters){++++}-{0:0}: join_transaction+0x1a4/0xc90 fs/btrfs/transaction.c:323 start_transaction+0x6b9/0x1650 fs/btrfs/transaction.c:708 btrfs_dirty_inode+0x9f/0x190 fs/btrfs/inode.c:6443 touch_atime+0x2f8/0x6b0 fs/inode.c:2271 file_accessed include/linux/fs.h:2263 [inline] filemap_read+0x105c/0x1240 mm/filemap.c:2877 __kernel_read+0x50d/0x9c0 fs/read_write.c:532 integrity_kernel_read+0x89/0xd0 security/integrity/iint.c:28 ima_calc_file_hash_tfm security/integrity/ima/ima_crypto.c:480 [inline] ima_calc_file_shash security/integrity/ima/ima_crypto.c:511 [inline] ima_calc_file_hash+0x12cf/0x1800 security/integrity/ima/ima_crypto.c:568 ima_collect_measurement+0x491/0x930 security/integrity/ima/ima_api.c:295 process_measurement+0x12d9/0x1c90 security/integrity/ima/ima_main.c:407 ima_file_check+0xe1/0x130 security/integrity/ima/ima_main.c:667 security_file_post_open+0xb3/0x260 security/security.c:2653 do_open fs/namei.c:4679 [inline] path_openat+0x2e88/0x38a0 fs/namei.c:4836 do_file_open+0x23e/0x4a0 fs/namei.c:4865 do_sys_openat2+0x113/0x200 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #3 (btrfs_trans_num_writers){++++}-{0:0}: __lock_release kernel/locking/lockdep.c:5574 [inline] lock_release+0x199/0x3d0 kernel/locking/lockdep.c:5889 percpu_up_read include/linux/percpu-rwsem.h:112 [inline] __sb_end_write include/linux/fs/super.h:14 [inline] sb_end_intwrite+0x26/0x1c0 include/linux/fs/super.h:101 __btrfs_end_transaction+0x248/0x640 fs/btrfs/transaction.c:1085 btrfs_dirty_inode+0x14c/0x190 fs/btrfs/inode.c:6457 touch_atime+0x2f8/0x6b0 fs/inode.c:2271 file_accessed include/linux/fs.h:2263 [inline] btrfs_file_mmap_prepare+0x189/0x200 fs/btrfs/file.c:2051 vfs_mmap_prepare include/linux/fs.h:2075 [inline] call_mmap_prepare mm/vma.c:2644 [inline] __mmap_region mm/vma.c:2743 [inline] mmap_region+0xddc/0x2230 mm/vma.c:2837 do_mmap+0xc2f/0x10c0 mm/mmap.c:559 vm_mmap_pgoff+0x2cc/0x4f0 mm/util.c:581 ksys_mmap_pgoff+0x4e8/0x720 mm/mmap.c:605 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #2 (&mm->mmap_lock){++++}-{4:4}: down_read_killable+0xa4/0x220 kernel/locking/rwsem.c:1560 mmap_read_lock_killable+0x1d/0x70 include/linux/mmap_lock.h:601 get_mmap_lock_carefully mm/mmap_lock.c:450 [inline] lock_mm_and_find_vma+0x2d7/0x340 mm/mmap_lock.c:501 do_user_addr_fault+0x330/0x1340 arch/x86/mm/fault.c:1357 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 filldir+0x2b5/0x690 fs/readdir.c:295 dir_emit include/linux/fs.h:3566 [inline] kernfs_fop_readdir+0x57e/0x8d0 fs/kernfs/dir.c:1915 iterate_dir+0x3a5/0x580 fs/readdir.c:108 __do_sys_getdents fs/readdir.c:327 [inline] __se_sys_getdents+0xf1/0x270 fs/readdir.c:312 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&root->kernfs_rwsem){++++}-{4:4}: down_write+0x3a/0x50 kernel/locking/rwsem.c:1590 kernfs_add_one+0x41/0x5c0 fs/kernfs/dir.c:796 kernfs_create_dir_ns+0xde/0x130 fs/kernfs/dir.c:1098 sysfs_create_dir_ns+0x12f/0x2a0 fs/sysfs/dir.c:59 create_dir lib/kobject.c:73 [inline] kobject_add_internal+0x631/0xd10 lib/kobject.c:240 kobject_add_varg lib/kobject.c:374 [inline] kobject_init_and_add+0x12b/0x1a0 lib/kobject.c:457 btrfs_sysfs_add_qgroups+0x116/0x2e0 fs/btrfs/sysfs.c:2604 btrfs_quota_enable+0x282/0x2850 fs/btrfs/qgroup.c:1034 btrfs_ioctl_quota_ctl+0x186/0x1c0 fs/btrfs/ioctl.c:3540 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+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&fs_info->qgroup_ioctl_lock){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/rtmutex_api.c:533 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:552 btrfs_quota_enable+0x2c6/0x2850 fs/btrfs/qgroup.c:1063 btrfs_ioctl_quota_ctl+0x186/0x1c0 fs/btrfs/ioctl.c:3540 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+0x14d/0xf80 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: &fs_info->qgroup_ioctl_lock --> btrfs_trans_num_writers --> btrfs_trans_num_extwriters Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(btrfs_trans_num_extwriters); lock(btrfs_trans_num_writers); lock(btrfs_trans_num_extwriters); lock(&fs_info->qgroup_ioctl_lock); *** DEADLOCK *** 5 locks held by syz.4.316/8295: #0: ffff888040026480 (sb_writers#28){.+.+}-{0:0}, at: mnt_want_write_file+0x63/0x210 fs/namespace.c:537 #1: ffff88806701d1b8 (&fs_info->subvol_sem){+.+.}-{4:4}, at: btrfs_ioctl_quota_ctl+0x17b/0x1c0 fs/btrfs/ioctl.c:3539 #2: ffff888040026770 (sb_internal#6){.+.+}-{0:0}, at: btrfs_quota_enable+0x2b9/0x2850 fs/btrfs/qgroup.c:1061 #3: ffff88806701f118 (btrfs_trans_num_writers){++++}-{0:0}, at: join_transaction+0x164/0xc90 fs/btrfs/transaction.c:322 #4: ffff88806701f140 (btrfs_trans_num_extwriters){++++}-{0:0}, at: join_transaction+0x164/0xc90 fs/btrfs/transaction.c:322 stack backtrace: CPU: 0 UID: 0 PID: 8295 Comm: syz.4.316 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043 check_noncircular+0x12e/0x150 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 kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/rtmutex_api.c:533 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:552 btrfs_quota_enable+0x2c6/0x2850 fs/btrfs/qgroup.c:1063 btrfs_ioctl_quota_ctl+0x186/0x1c0 fs/btrfs/ioctl.c:3540 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+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f7ba66dc819 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f7ba4915028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f7ba6956090 RCX: 00007f7ba66dc819 RDX: 00002000000000c0 RSI: 00000000c0109428 RDI: 0000000000000003 RBP: 00007f7ba6772c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f7ba6956128 R14: 00007f7ba6956090 R15: 00007ffdebe3e418 BTRFS info (device loop4): setting incompat feature flag for SIMPLE_QUOTA (0x10000)