====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.1.3982/20628 is trying to acquire lock: ffff88808779d038 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock_killable+0x1d/0x70 include/linux/mmap_lock.h:609 but task is already holding lock: ffff88801c2cc980 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_fop_readdir+0x26d/0x960 fs/kernfs/dir.c:1982 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #6 (&root->kernfs_rwsem){++++}-{4:4}: down_write+0x96/0x200 kernel/locking/rwsem.c:1631 kernfs_add_one+0x41/0x6f0 fs/kernfs/dir.c:825 kernfs_create_dir_ns+0x1a1/0x230 fs/kernfs/dir.c:1130 sysfs_create_dir_ns+0x12f/0x2a0 fs/sysfs/dir.c:59 create_dir lib/kobject.c:73 [inline] kobject_add_internal+0x622/0xcd0 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+0x118/0x2f0 fs/btrfs/sysfs.c:2604 btrfs_quota_enable+0x274/0x1e20 fs/btrfs/qgroup.c:1032 btrfs_ioctl_quota_ctl+0x186/0x1f0 fs/btrfs/ioctl.c:3566 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:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #5 (&fs_info->qgroup_ioctl_lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x19d/0x1550 kernel/locking/mutex.c:821 btrfs_quota_enable+0x2b1/0x1e20 fs/btrfs/qgroup.c:1061 btrfs_ioctl_quota_ctl+0x186/0x1f0 fs/btrfs/ioctl.c:3566 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:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #4 (btrfs_trans_num_extwriters){++++}-{0:0}: join_transaction+0x18a/0xd40 fs/btrfs/transaction.c:324 start_transaction+0x6ed/0x17d0 fs/btrfs/transaction.c:718 btrfs_dirty_inode+0x9f/0x190 fs/btrfs/inode.c:6446 touch_atime+0x2f8/0x670 fs/inode.c:2326 file_accessed include/linux/fs.h:2278 [inline] filemap_read+0xffc/0x11e0 mm/filemap.c:2896 __kernel_read+0x4ca/0x960 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:222 [inline] ima_calc_file_hash+0x451/0x890 security/integrity/ima/ima_crypto.c:280 ima_collect_measurement+0x51b/0xa00 security/integrity/ima/ima_api.c:300 process_measurement+0x1272/0x1c10 security/integrity/ima/ima_main.c:425 ima_file_check+0xe1/0x130 security/integrity/ima/ima_main.c:685 security_file_post_open+0xb3/0x260 security/security.c:2755 do_open fs/namei.c:4839 [inline] path_openat+0x1485/0x1d60 fs/namei.c:5000 do_file_open+0x23e/0x4a0 fs/namei.c:5029 do_sys_openat2+0x115/0x200 fs/open.c:1417 do_sys_open fs/open.c:1423 [inline] __do_sys_openat fs/open.c:1439 [inline] __se_sys_openat fs/open.c:1434 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1434 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #3 (btrfs_trans_num_writers){++++}-{0:0}: __lock_release kernel/locking/lockdep.c:5592 [inline] lock_release+0x199/0x3c0 kernel/locking/lockdep.c:5907 percpu_up_read include/linux/percpu-rwsem.h:114 [inline] __sb_end_write include/linux/fs/super.h:14 [inline] sb_end_intwrite+0x26/0x190 include/linux/fs/super.h:101 __btrfs_end_transaction+0x23f/0x640 fs/btrfs/transaction.c:1095 btrfs_dirty_inode+0x14c/0x190 fs/btrfs/inode.c:6460 file_update_time_flags+0x285/0x440 fs/inode.c:2481 btrfs_page_mkwrite+0x5e3/0x1a40 fs/btrfs/file.c:1878 do_page_mkwrite+0x147/0x310 mm/memory.c:3754 wp_page_shared mm/memory.c:4155 [inline] do_wp_page+0x1a9c/0x4b80 mm/memory.c:4378 handle_pte_fault mm/memory.c:6520 [inline] __handle_mm_fault mm/memory.c:6645 [inline] handle_mm_fault+0x1576/0x3720 mm/memory.c:6814 do_user_addr_fault+0xa4f/0x1340 arch/x86/mm/fault.c:1343 handle_page_fault arch/x86/mm/fault.c:1483 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1536 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595 -> #2 (sb_pagefaults#3){.+.+}-{0:0}: 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/super.h:19 [inline] sb_start_pagefault include/linux/fs/super.h:159 [inline] btrfs_page_mkwrite+0x303/0x1a40 fs/btrfs/file.c:1837 do_page_mkwrite+0x147/0x310 mm/memory.c:3754 wp_page_shared mm/memory.c:4155 [inline] do_wp_page+0x1a9c/0x4b80 mm/memory.c:4378 handle_pte_fault mm/memory.c:6520 [inline] __handle_mm_fault mm/memory.c:6645 [inline] handle_mm_fault+0x1576/0x3720 mm/memory.c:6814 do_user_addr_fault+0xa4f/0x1340 arch/x86/mm/fault.c:1343 handle_page_fault arch/x86/mm/fault.c:1483 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1536 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595 -> #1 (vm_lock){++++}-{0:0}: __vma_start_exclude_readers+0x283/0x930 mm/mmap_lock.c:125 __vma_start_write+0xdc/0x290 mm/mmap_lock.c:148 vma_start_write include/linux/mmap_lock.h:303 [inline] mprotect_fixup+0x657/0xad0 mm/mprotect.c:836 setup_arg_pages+0x658/0xbd0 fs/exec.c:675 load_elf_binary+0xc6c/0x28d0 fs/binfmt_elf.c:1028 search_binary_handler fs/exec.c:1759 [inline] exec_binprm fs/exec.c:1791 [inline] bprm_execve+0x930/0x1590 fs/exec.c:1847 kernel_execve+0x8c3/0x9c0 fs/exec.c:1991 try_to_run_init_process+0x13/0x60 init/main.c:1486 kernel_init+0xb2/0x1d0 init/main.c:1616 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #0 (&mm->mmap_lock){++++}-{4:4}: check_prev_add kernel/locking/lockdep.c:3181 [inline] check_prevs_add kernel/locking/lockdep.c:3300 [inline] validate_chain kernel/locking/lockdep.c:3924 [inline] __lock_acquire+0x1520/0x2cf0 kernel/locking/lockdep.c:5253 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5886 down_read_killable+0x50/0x3b0 kernel/locking/rwsem.c:1599 mmap_read_lock_killable+0x1d/0x70 include/linux/mmap_lock.h:609 get_mmap_lock_carefully mm/mmap_lock.c:450 [inline] lock_mm_and_find_vma+0x2d6/0x340 mm/mmap_lock.c:501 do_user_addr_fault+0x343/0x1340 arch/x86/mm/fault.c:1366 handle_page_fault arch/x86/mm/fault.c:1483 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1536 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595 filldir+0x2bd/0x630 fs/readdir.c:-1 dir_emit include/linux/fs.h:3608 [inline] kernfs_fop_readdir+0x580/0x960 fs/kernfs/dir.c:1999 iterate_dir+0x2e2/0x4d0 fs/readdir.c:110 __do_sys_getdents fs/readdir.c:319 [inline] __se_sys_getdents+0xf1/0x270 fs/readdir.c:304 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: &mm->mmap_lock --> &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(&mm->mmap_lock); *** DEADLOCK *** locks held by syz.1.3982/20628: 3, last CPU#0: #0: ffff888028fe49b0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259 #1: ffff88805d9b1900 (&type->i_mutex_dir_key#4){++++}-{4:4}, at: iterate_dir+0x209/0x4d0 fs/readdir.c:103 #2: ffff88801c2cc980 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_fop_readdir+0x26d/0x960 fs/kernfs/dir.c:1982 stack backtrace: CPU: 0 UID: 0 PID: 20628 Comm: syz.1.3982 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2059 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2191 check_prev_add kernel/locking/lockdep.c:3181 [inline] check_prevs_add kernel/locking/lockdep.c:3300 [inline] validate_chain kernel/locking/lockdep.c:3924 [inline] __lock_acquire+0x1520/0x2cf0 kernel/locking/lockdep.c:5253 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5886 down_read_killable+0x50/0x3b0 kernel/locking/rwsem.c:1599 mmap_read_lock_killable+0x1d/0x70 include/linux/mmap_lock.h:609 get_mmap_lock_carefully mm/mmap_lock.c:450 [inline] lock_mm_and_find_vma+0x2d6/0x340 mm/mmap_lock.c:501 do_user_addr_fault+0x343/0x1340 arch/x86/mm/fault.c:1366 handle_page_fault arch/x86/mm/fault.c:1483 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1536 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595 RIP: 0010:filldir+0x2bd/0x630 fs/readdir.c:290 Code: 79 b4 76 ff 0f 01 cb 48 8b 44 24 20 49 89 47 08 48 bd 00 00 00 00 00 fc ff df 48 8b 44 24 40 48 89 03 8b 4c 24 04 48 8d 43 10 <66> 89 08 8b 54 24 14 80 e2 0f 89 c9 48 8d 04 0b 48 ff c8 88 10 48 RSP: 0018:ffffc90005407c50 EFLAGS: 00050297 RAX: 0000200000002000 RBX: 0000200000001ff0 RCX: 0000000000000020 RDX: 0000000000000002 RSI: 0000000000000006 RDI: 0000000000000007 RBP: dffffc0000000000 R08: ffff88802c5e3e87 R09: 1ffff110058bc7d0 R10: dffffc0000000000 R11: ffffed10058bc7d1 R12: ffffffff8c0bf200 R13: 0000000000000006 R14: 0000000000000006 R15: 0000200000001fd8 dir_emit include/linux/fs.h:3608 [inline] kernfs_fop_readdir+0x580/0x960 fs/kernfs/dir.c:1999 iterate_dir+0x2e2/0x4d0 fs/readdir.c:110 __do_sys_getdents fs/readdir.c:319 [inline] __se_sys_getdents+0xf1/0x270 fs/readdir.c:304 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff62959e0d9 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:00007ff62a3b0028 EFLAGS: 00000246 ORIG_RAX: 000000000000004e RAX: ffffffffffffffda RBX: 00007ff629825fa0 RCX: 00007ff62959e0d9 RDX: 00000000000000b8 RSI: 0000200000001fc0 RDI: 0000000000000005 RBP: 00007ff629635024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff629826038 R14: 00007ff629825fa0 R15: 00007ffd878c23d8 ---------------- Code disassembly (best guess): 0: 79 b4 jns 0xffffffb6 2: 76 ff jbe 0x3 4: 0f 01 cb stac 7: 48 8b 44 24 20 mov 0x20(%rsp),%rax c: 49 89 47 08 mov %rax,0x8(%r15) 10: 48 bd 00 00 00 00 00 movabs $0xdffffc0000000000,%rbp 17: fc ff df 1a: 48 8b 44 24 40 mov 0x40(%rsp),%rax 1f: 48 89 03 mov %rax,(%rbx) 22: 8b 4c 24 04 mov 0x4(%rsp),%ecx 26: 48 8d 43 10 lea 0x10(%rbx),%rax * 2a: 66 89 08 mov %cx,(%rax) <-- trapping instruction 2d: 8b 54 24 14 mov 0x14(%rsp),%edx 31: 80 e2 0f and $0xf,%dl 34: 89 c9 mov %ecx,%ecx 36: 48 8d 04 0b lea (%rbx,%rcx,1),%rax 3a: 48 ff c8 dec %rax 3d: 88 10 mov %dl,(%rax) 3f: 48 rex.W