BTRFS info (device loop1): enabling ssd optimizations BTRFS info (device loop1): turning on async discard BTRFS info (device loop1): enabling free space tree ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.1.1420/14282 is trying to acquire lock: ffff88801c6f0188 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_add_one+0x41/0x520 fs/kernfs/dir.c:791 but task is already holding lock: ffff888042519998 (&fs_info->qgroup_ioctl_lock){+.+.}-{4:4}, at: btrfs_quota_enable+0x214/0x2920 fs/btrfs/qgroup.c:1018 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&fs_info->qgroup_ioctl_lock){+.+.}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760 btrfs_create_qgroup+0x55/0x520 fs/btrfs/qgroup.c:1666 create_pending_snapshot+0x86c/0x3280 fs/btrfs/transaction.c:1731 create_pending_snapshots+0x17c/0x1c0 fs/btrfs/transaction.c:1923 btrfs_commit_transaction+0xeea/0x3950 fs/btrfs/transaction.c:2411 create_snapshot+0x6bc/0xba0 fs/btrfs/ioctl.c:782 btrfs_mksubvol+0x545/0x6d0 fs/btrfs/ioctl.c:934 btrfs_mksnapshot+0xab/0xf0 fs/btrfs/ioctl.c:978 __btrfs_ioctl_snap_create+0x520/0x730 fs/btrfs/ioctl.c:1242 btrfs_ioctl_snap_create+0x131/0x180 fs/btrfs/ioctl.c:1269 btrfs_ioctl+0x447/0xd00 fs/btrfs/ioctl.c:-1 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/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 -> #6 (&fs_info->reloc_mutex){+.+.}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760 btrfs_commit_transaction+0xedd/0x3950 fs/btrfs/transaction.c:2404 sync_filesystem+0x1cf/0x230 fs/sync.c:66 generic_shutdown_super+0x6f/0x2c0 fs/super.c:621 kill_anon_super+0x3b/0x70 fs/super.c:1281 btrfs_kill_super+0x41/0x50 fs/btrfs/super.c:2134 deactivate_locked_super+0xbc/0x130 fs/super.c:473 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1327 task_work_run+0x1d4/0x260 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xe9/0x130 kernel/entry/common.c:43 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #5 (btrfs_trans_unblocked){++++}-{0:0}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 wait_current_trans+0x22b/0x520 fs/btrfs/transaction.c:530 start_transaction+0x6a5/0x1610 fs/btrfs/transaction.c:701 btrfs_replace_file_extents+0x2b1/0x1de0 fs/btrfs/file.c:2432 insert_prealloc_file_extent fs/btrfs/inode.c:9023 [inline] __btrfs_prealloc_file_range+0x48d/0xcf0 fs/btrfs/inode.c:9090 btrfs_prealloc_file_range+0x40/0x60 fs/btrfs/inode.c:9168 btrfs_fallocate+0x14a1/0x1c10 fs/btrfs/file.c:3239 vfs_fallocate+0x669/0x7e0 fs/open.c:342 ksys_fallocate fs/open.c:366 [inline] __do_sys_fallocate fs/open.c:371 [inline] __se_sys_fallocate fs/open.c:369 [inline] __x64_sys_fallocate+0xc0/0x110 fs/open.c:369 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 (sb_internal#3){.+.+}-{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_intwrite include/linux/fs.h:2099 [inline] start_transaction+0x56f/0x1610 fs/btrfs/transaction.c:698 btrfs_dirty_inode+0x9f/0x190 fs/btrfs/inode.c:6282 inode_update_time fs/inode.c:2117 [inline] __file_update_time fs/inode.c:2345 [inline] file_update_time+0x347/0x490 fs/inode.c:2375 btrfs_page_mkwrite+0x5c8/0x1a70 fs/btrfs/file.c:1916 do_page_mkwrite+0x14d/0x310 mm/memory.c:3532 wp_page_shared mm/memory.c:3933 [inline] do_wp_page+0x268d/0x5800 mm/memory.c:4152 handle_pte_fault mm/memory.c:6237 [inline] __handle_mm_fault+0x102e/0x5440 mm/memory.c:6363 handle_mm_fault+0x40a/0x8e0 mm/memory.c:6532 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 -> #3 (sb_pagefaults#2){.+.+}-{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+0x317/0x1a70 fs/btrfs/file.c:1875 do_page_mkwrite+0x14d/0x310 mm/memory.c:3532 wp_page_shared mm/memory.c:3933 [inline] do_wp_page+0x268d/0x5800 mm/memory.c:4152 handle_pte_fault mm/memory.c:6237 [inline] __handle_mm_fault+0x102e/0x5440 mm/memory.c:6363 handle_mm_fault+0x40a/0x8e0 mm/memory.c:6532 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 -> #2 (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:819 setup_arg_pages+0x52a/0xa90 fs/exec.c:670 load_elf_binary+0xba4/0x2740 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 -> #1 (&mm->mmap_lock){++++}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 down_read_killable+0x50/0x350 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+0x2c0/0x6c0 fs/readdir.c:297 dir_emit include/linux/fs.h:3987 [inline] kernfs_fop_readdir+0x537/0x870 fs/kernfs/dir.c:1910 iterate_dir+0x399/0x570 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 -> #0 (&root->kernfs_rwsem){++++}-{4:4}: 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 down_write+0x96/0x1f0 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+0x59f/0xb40 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:2644 btrfs_quota_enable+0x25d/0x2920 fs/btrfs/qgroup.c:1022 btrfs_ioctl_quota_ctl+0x183/0x1c0 fs/btrfs/ioctl.c:3667 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/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 other info that might help us debug this: Chain exists of: &root->kernfs_rwsem --> &fs_info->reloc_mutex --> &fs_info->qgroup_ioctl_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->qgroup_ioctl_lock); lock(&fs_info->reloc_mutex); lock(&fs_info->qgroup_ioctl_lock); lock(&root->kernfs_rwsem); *** DEADLOCK *** 3 locks held by syz.1.1420/14282: #0: ffff888089b0a420 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write_file+0x60/0x200 fs/namespace.c:552 #1: ffff888042518c60 (&fs_info->subvol_sem){++++}-{4:4}, at: btrfs_ioctl_quota_ctl+0x178/0x1c0 fs/btrfs/ioctl.c:3666 #2: ffff888042519998 (&fs_info->qgroup_ioctl_lock){+.+.}-{4:4}, at: btrfs_quota_enable+0x214/0x2920 fs/btrfs/qgroup.c:1018 stack backtrace: CPU: 1 UID: 0 PID: 14282 Comm: syz.1.1420 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 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 down_write+0x96/0x1f0 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+0x59f/0xb40 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:2644 btrfs_quota_enable+0x25d/0x2920 fs/btrfs/qgroup.c:1022 btrfs_ioctl_quota_ctl+0x183/0x1c0 fs/btrfs/ioctl.c:3667 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/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 RIP: 0033:0x7f8041f8efc9 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:00007f8042eaf038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f80421e5fa0 RCX: 00007f8041f8efc9 RDX: 00002000000000c0 RSI: 00000000c0109428 RDI: 0000000000000003 RBP: 00007f8042011f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f80421e6038 R14: 00007f80421e5fa0 R15: 00007ffd0a650298 BTRFS info (device loop1): setting incompat feature flag for SIMPLE_QUOTA (0x10000)