EXT4-fs (loop3): mounted filesystem without journal. Opts: ,errors=continue. Quota mode: none. ====================================================== WARNING: possible circular locking dependency detected 5.15.184-syzkaller #0 Not tainted ------------------------------------------------------ syz.3.764/7816 is trying to acquire lock: ffff88807b02ce28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock+0x1c/0x50 include/linux/mmap_lock.h:117 but task is already holding lock: ffff88807f0083f0 (&type->i_mutex_dir_key#4){++++}-{3:3}, at: iterate_dir+0x10d/0x560 fs/readdir.c:55 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (&type->i_mutex_dir_key#4){++++}-{3:3}: down_read+0x44/0x2e0 kernel/locking/rwsem.c:1498 inode_lock_shared include/linux/fs.h:797 [inline] lookup_slow+0x46/0x70 fs/namei.c:1679 walk_component+0x319/0x460 fs/namei.c:1976 lookup_last fs/namei.c:2431 [inline] path_lookupat+0x169/0x440 fs/namei.c:2455 filename_lookup+0x1e2/0x4f0 fs/namei.c:2484 kern_path+0x37/0x190 fs/namei.c:2582 lookup_bdev+0xbd/0x270 block/bdev.c:982 device_matched fs/btrfs/volumes.c:568 [inline] btrfs_free_stale_devices+0x6db/0xa60 fs/btrfs/volumes.c:608 btrfs_forget_devices+0x52/0x80 fs/btrfs/volumes.c:1431 btrfs_control_ioctl+0x104/0x220 fs/btrfs/super.c:2450 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #4 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock_common+0x1eb/0x2390 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 write_all_supers+0x109d/0x40d0 fs/btrfs/disk-io.c:4159 btrfs_sync_log+0x1e89/0x2790 fs/btrfs/tree-log.c:3327 btrfs_sync_file+0xc3c/0x10d0 fs/btrfs/file.c:2371 generic_write_sync include/linux/fs.h:2989 [inline] btrfs_file_write_iter+0xc8b/0xe00 fs/btrfs/file.c:2099 do_iter_readv_writev+0x497/0x600 fs/read_write.c:-1 do_iter_write+0x205/0x7b0 fs/read_write.c:855 iter_file_splice_write+0x65f/0xc40 fs/splice.c:689 do_splice_from fs/splice.c:767 [inline] direct_splice_actor+0xe1/0x130 fs/splice.c:936 splice_direct_to_actor+0x4dc/0xb50 fs/splice.c:891 do_splice_direct+0x1b9/0x2c0 fs/splice.c:979 do_sendfile+0x5d5/0xec0 fs/read_write.c:1249 __do_sys_sendfile64 fs/read_write.c:1317 [inline] __se_sys_sendfile64+0x13b/0x190 fs/read_write.c:1303 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #3 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock_common+0x1eb/0x2390 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 btrfs_sync_log+0x1da0/0x2790 fs/btrfs/tree-log.c:3308 btrfs_sync_file+0xc3c/0x10d0 fs/btrfs/file.c:2371 generic_write_sync include/linux/fs.h:2989 [inline] btrfs_file_write_iter+0xc8b/0xe00 fs/btrfs/file.c:2099 do_iter_readv_writev+0x497/0x600 fs/read_write.c:-1 do_iter_write+0x205/0x7b0 fs/read_write.c:855 iter_file_splice_write+0x65f/0xc40 fs/splice.c:689 do_splice_from fs/splice.c:767 [inline] direct_splice_actor+0xe1/0x130 fs/splice.c:936 splice_direct_to_actor+0x4dc/0xb50 fs/splice.c:891 do_splice_direct+0x1b9/0x2c0 fs/splice.c:979 do_sendfile+0x5d5/0xec0 fs/read_write.c:1249 __do_sys_sendfile64 fs/read_write.c:1317 [inline] __se_sys_sendfile64+0x13b/0x190 fs/read_write.c:1303 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #2 (sb_internal#2){.+.+}-{0:0}: percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1811 [inline] sb_start_intwrite include/linux/fs.h:1928 [inline] start_transaction+0x5bc/0x1130 fs/btrfs/transaction.c:680 btrfs_dirty_inode+0xc5/0x1c0 fs/btrfs/inode.c:6436 inode_update_time fs/inode.c:1893 [inline] file_update_time+0x373/0x400 fs/inode.c:2083 btrfs_page_mkwrite+0x35e/0xc50 fs/btrfs/inode.c:8938 do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922 do_shared_fault mm/memory.c:4328 [inline] do_fault mm/memory.c:4396 [inline] handle_pte_fault mm/memory.c:4650 [inline] __handle_mm_fault mm/memory.c:4785 [inline] handle_mm_fault+0x1d4b/0x43c0 mm/memory.c:4883 do_user_addr_fault+0x489/0xc80 arch/x86/mm/fault.c:1357 handle_page_fault arch/x86/mm/fault.c:1445 [inline] exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1501 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606 -> #1 (sb_pagefaults#2){.+.+}-{0:0}: percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1811 [inline] sb_start_pagefault include/linux/fs.h:1910 [inline] btrfs_page_mkwrite+0x1ac/0xc50 fs/btrfs/inode.c:8922 do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922 do_shared_fault mm/memory.c:4328 [inline] do_fault mm/memory.c:4396 [inline] handle_pte_fault mm/memory.c:4650 [inline] __handle_mm_fault mm/memory.c:4785 [inline] handle_mm_fault+0x1d4b/0x43c0 mm/memory.c:4883 do_user_addr_fault+0x489/0xc80 arch/x86/mm/fault.c:1357 handle_page_fault arch/x86/mm/fault.c:1445 [inline] exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1501 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606 -> #0 (&mm->mmap_lock){++++}-{3:3}: check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623 down_read+0x44/0x2e0 kernel/locking/rwsem.c:1498 mmap_read_lock+0x1c/0x50 include/linux/mmap_lock.h:117 do_user_addr_fault+0xc35/0xc80 arch/x86/mm/fault.c:1308 handle_page_fault arch/x86/mm/fault.c:1445 [inline] exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1501 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606 user_access_begin arch/x86/include/asm/uaccess.h:574 [inline] filldir+0x300/0x720 fs/readdir.c:249 dir_emit include/linux/fs.h:3713 [inline] ext4_readdir+0x14dc/0x3a60 fs/ext4/dir.c:275 iterate_dir+0x218/0x560 fs/readdir.c:-1 __do_sys_getdents fs/readdir.c:286 [inline] __se_sys_getdents+0xe5/0x250 fs/readdir.c:271 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 other info that might help us debug this: Chain exists of: &mm->mmap_lock --> &fs_devs->device_list_mutex --> &type->i_mutex_dir_key#4 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&type->i_mutex_dir_key#4); lock(&fs_devs->device_list_mutex); lock(&type->i_mutex_dir_key#4); lock(&mm->mmap_lock); *** DEADLOCK *** 2 locks held by syz.3.764/7816: #0: ffff8880781aaff0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1058 #1: ffff88807f0083f0 (&type->i_mutex_dir_key#4){++++}-{3:3}, at: iterate_dir+0x10d/0x560 fs/readdir.c:55 stack backtrace: CPU: 0 PID: 7816 Comm: syz.3.764 Not tainted 5.15.184-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2133 check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623 down_read+0x44/0x2e0 kernel/locking/rwsem.c:1498 mmap_read_lock+0x1c/0x50 include/linux/mmap_lock.h:117 do_user_addr_fault+0xc35/0xc80 arch/x86/mm/fault.c:1308 handle_page_fault arch/x86/mm/fault.c:1445 [inline] exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1501 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606 RIP: 0010:filldir+0x300/0x720 fs/readdir.c:253 Code: 31 ab ff 4c 01 fd 0f 82 66 02 00 00 48 b8 00 f0 ff ff ff 7f 00 00 48 39 c5 0f 87 53 02 00 00 0f 01 cb 0f ae e8 48 8b 44 24 50 <49> 89 47 08 48 8b 04 24 48 8b 4c 24 10 48 8b 54 24 58 48 89 11 66 RSP: 0018:ffffc9000397faa8 EFLAGS: 00050287 RAX: 0000000000000000 RBX: ffffc9000397fe70 RCX: ffff8880246f1dc0 RDX: 0000000000000002 RSI: 0000200000001fd8 RDI: 00007ffffffff000 RBP: 0000200000001fd8 R08: 0000000000000002 R09: 0000000000000004 R10: 000000000000002e R11: 0000000000000002 R12: 0000200000001fd8 R13: ffff888076bc9008 R14: 0000000000000001 R15: 0000200000001fc0 dir_emit include/linux/fs.h:3713 [inline] ext4_readdir+0x14dc/0x3a60 fs/ext4/dir.c:275 iterate_dir+0x218/0x560 fs/readdir.c:-1 __do_sys_getdents fs/readdir.c:286 [inline] __se_sys_getdents+0xe5/0x250 fs/readdir.c:271 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f5c84a8b969 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:00007f5c828d2038 EFLAGS: 00000246 ORIG_RAX: 000000000000004e RAX: ffffffffffffffda RBX: 00007f5c84cb3080 RCX: 00007f5c84a8b969 RDX: 00000000000000b8 RSI: 0000200000001fc0 RDI: 0000000000000007 RBP: 00007f5c84b0dab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f5c84cb3080 R15: 00007fff9402c488 ---------------- Code disassembly (best guess): 0: 31 ab ff 4c 01 fd xor %ebp,-0x2feb301(%rbx) 6: 0f 82 66 02 00 00 jb 0x272 c: 48 b8 00 f0 ff ff ff movabs $0x7ffffffff000,%rax 13: 7f 00 00 16: 48 39 c5 cmp %rax,%rbp 19: 0f 87 53 02 00 00 ja 0x272 1f: 0f 01 cb stac 22: 0f ae e8 lfence 25: 48 8b 44 24 50 mov 0x50(%rsp),%rax * 2a: 49 89 47 08 mov %rax,0x8(%r15) <-- trapping instruction 2e: 48 8b 04 24 mov (%rsp),%rax 32: 48 8b 4c 24 10 mov 0x10(%rsp),%rcx 37: 48 8b 54 24 58 mov 0x58(%rsp),%rdx 3c: 48 89 11 mov %rdx,(%rcx) 3f: 66 data16