====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.0.280/7752 is trying to acquire lock: ffff88803145a770 (sb_internal#2){.+.+}-{0:0}, at: btrfs_dirty_inode+0x9f/0x190 fs/btrfs/inode.c:6272 but task is already holding lock: ffff88803145a5f8 (sb_pagefaults#4){.+.+}-{0:0}, at: do_page_mkwrite+0x150/0x310 mm/memory.c:3489 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (sb_pagefaults#4){.+.+}-{0:0}: 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:3489 wp_page_shared mm/memory.c:3890 [inline] do_wp_page+0x25c8/0x4930 mm/memory.c:4109 handle_pte_fault mm/memory.c:6211 [inline] __handle_mm_fault mm/memory.c:6336 [inline] handle_mm_fault+0x97c/0x3400 mm/memory.c:6505 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 -> #6 (vm_lock){++++}-{0:0}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __vma_enter_locked+0x182/0x380 mm/mmap_lock.c:63 __vma_start_write+0x1e/0x120 mm/mmap_lock.c:87 vma_start_write include/linux/mmap_lock.h:212 [inline] mprotect_fixup+0x578/0x9c0 mm/mprotect.c:828 setup_arg_pages+0x52a/0xa90 fs/exec.c:670 load_elf_binary+0xbad/0x2750 fs/binfmt_elf.c:1028 search_binary_handler fs/exec.c:1670 [inline] exec_binprm fs/exec.c:1702 [inline] bprm_execve+0x99c/0x1450 fs/exec.c:1754 kernel_execve+0x8f0/0x9f0 fs/exec.c:1920 try_to_run_init_process+0x13/0x60 init/main.c:1411 kernel_init+0xad/0x1d0 init/main.c:1539 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #5 (&mm->mmap_lock){++++}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 down_read_killable+0x9d/0x220 kernel/locking/rwsem.c:1560 mmap_read_lock_killable+0x1d/0x70 include/linux/mmap_lock.h:377 get_mmap_lock_carefully mm/mmap_lock.c:377 [inline] lock_mm_and_find_vma+0x2a8/0x300 mm/mmap_lock.c:428 do_user_addr_fault+0x331/0x1380 arch/x86/mm/fault.c:1359 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 filldir+0x2b6/0x6c0 fs/readdir.c:295 dir_emit include/linux/fs.h:3988 [inline] kernfs_fop_readdir+0x53a/0x870 fs/kernfs/dir.c:1910 iterate_dir+0x3a5/0x580 fs/readdir.c:108 __do_sys_getdents fs/readdir.c:326 [inline] __se_sys_getdents+0xe4/0x250 fs/readdir.c:312 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 -> #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_ioctl_subvol_setflags+0x461/0x820 fs/btrfs/ioctl.c:1419 btrfs_ioctl+0x93d/0xd00 fs/btrfs/ioctl.c:5255 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 -> #1 (btrfs_trans_num_writers){++++}-{0:0}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 join_transaction+0x182/0xca0 fs/btrfs/transaction.c:320 start_transaction+0x6b6/0x1620 fs/btrfs/transaction.c:705 btrfs_ioctl_subvol_setflags+0x461/0x820 fs/btrfs/ioctl.c:1419 btrfs_ioctl+0x93d/0xd00 fs/btrfs/ioctl.c:5255 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 -> #0 (sb_internal#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_intwrite include/linux/fs.h:2099 [inline] start_transaction+0x56e/0x1620 fs/btrfs/transaction.c:699 btrfs_dirty_inode+0x9f/0x190 fs/btrfs/inode.c:6272 inode_update_time fs/inode.c:2129 [inline] __file_update_time fs/inode.c:2357 [inline] file_update_time+0x34d/0x490 fs/inode.c:2387 btrfs_page_mkwrite+0x5dd/0x1a80 fs/btrfs/file.c:1915 do_page_mkwrite+0x150/0x310 mm/memory.c:3489 wp_page_shared mm/memory.c:3890 [inline] do_wp_page+0x25c8/0x4930 mm/memory.c:4109 handle_pte_fault mm/memory.c:6211 [inline] __handle_mm_fault mm/memory.c:6336 [inline] handle_mm_fault+0x97c/0x3400 mm/memory.c:6505 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 other info that might help us debug this: Chain exists of: sb_internal#2 --> vm_lock --> sb_pagefaults#4 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(sb_pagefaults#4); lock(vm_lock); lock(sb_pagefaults#4); rlock(sb_internal#2); *** DEADLOCK *** 2 locks held by syz.0.280/7752: #0: ffff8880350fe1c8 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1a3/0x450 mm/mmap_lock.c:238 #1: ffff88803145a5f8 (sb_pagefaults#4){.+.+}-{0:0}, at: do_page_mkwrite+0x150/0x310 mm/memory.c:3489 stack backtrace: CPU: 1 UID: 0 PID: 7752 Comm: syz.0.280 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: 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_intwrite include/linux/fs.h:2099 [inline] start_transaction+0x56e/0x1620 fs/btrfs/transaction.c:699 btrfs_dirty_inode+0x9f/0x190 fs/btrfs/inode.c:6272 inode_update_time fs/inode.c:2129 [inline] __file_update_time fs/inode.c:2357 [inline] file_update_time+0x34d/0x490 fs/inode.c:2387 btrfs_page_mkwrite+0x5dd/0x1a80 fs/btrfs/file.c:1915 do_page_mkwrite+0x150/0x310 mm/memory.c:3489 wp_page_shared mm/memory.c:3890 [inline] do_wp_page+0x25c8/0x4930 mm/memory.c:4109 handle_pte_fault mm/memory.c:6211 [inline] __handle_mm_fault mm/memory.c:6336 [inline] handle_mm_fault+0x97c/0x3400 mm/memory.c:6505 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 RIP: 0033:0x7f07903f7398 Code: fc 89 37 c3 c5 fa 6f 06 c5 fa 6f 4c 16 f0 c5 fa 7f 07 c5 fa 7f 4c 17 f0 c3 66 0f 1f 84 00 00 00 00 00 48 8b 4c 16 f8 48 8b 36 <48> 89 37 48 89 4c 17 f8 c3 c5 fe 6f 54 16 e0 c5 fe 6f 5c 16 c0 c5 RSP: 002b:00007ffe9a41bd78 EFLAGS: 00010246 RAX: 0000200000000100 RBX: 0000000000000004 RCX: 0031656c69662f2e RDX: 0000000000000008 RSI: 0031656c69662f2e RDI: 0000200000000100 RBP: 00007f0790687da0 R08: 0000001b2e220000 R09: 0000000000000001 R10: 0000000000000001 R11: 0000000000000009 R12: 00007f0790685fac R13: 00007f0790685fa0 R14: fffffffffffffffe R15: 00007ffe9a41be90