====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.4.878/8024 is trying to acquire lock: ffff0000de552090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27 but task is already holding lock: ffff0000f7758558 (sb_pagefaults#3){.+.+}-{0:0}, at: do_page_mkwrite+0x13c/0x358 mm/memory.c:3009 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (sb_pagefaults#3){.+.+}-{0:0}: percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1891 [inline] sb_start_pagefault include/linux/fs.h:1995 [inline] filemap_page_mkwrite+0x15c/0x884 mm/filemap.c:3545 do_page_mkwrite+0x13c/0x358 mm/memory.c:3009 do_shared_fault mm/memory.c:4694 [inline] do_fault mm/memory.c:4762 [inline] handle_pte_fault mm/memory.c:5029 [inline] __handle_mm_fault mm/memory.c:5171 [inline] handle_mm_fault+0x13fc/0x2fb0 mm/memory.c:5292 __do_page_fault arch/arm64/mm/fault.c:499 [inline] do_page_fault+0x4e4/0x98c arch/arm64/mm/fault.c:583 do_translation_fault+0x94/0xc8 arch/arm64/mm/fault.c:667 do_mem_abort+0x70/0x194 arch/arm64/mm/fault.c:804 el0_da+0x70/0x144 arch/arm64/kernel/entry-common.c:515 el0t_64_sync_handler+0x90/0xf0 arch/arm64/kernel/entry-common.c:658 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 -> #1 (&mm->mmap_lock){++++}-{3:3}: __might_fault+0xc4/0x124 mm/memory.c:5850 reiserfs_ioctl+0x140/0x450 fs/reiserfs/ioctl.c:96 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 -> #0 (&sbi->lock){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x2880/0x6800 kernel/locking/lockdep.c:5049 lock_acquire+0x20c/0x63c kernel/locking/lockdep.c:5662 __mutex_lock_common+0x190/0x1f60 kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799 reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27 reiserfs_dirty_inode+0xf0/0x224 fs/reiserfs/super.c:704 __mark_inode_dirty+0x2e8/0x11ac fs/fs-writeback.c:2449 generic_update_time fs/inode.c:1946 [inline] inode_update_time fs/inode.c:1959 [inline] __file_update_time+0x1f4/0x21c fs/inode.c:2147 file_update_time+0x270/0x2ec fs/inode.c:2178 filemap_page_mkwrite+0x31c/0x884 mm/filemap.c:3546 do_page_mkwrite+0x13c/0x358 mm/memory.c:3009 do_shared_fault mm/memory.c:4694 [inline] do_fault mm/memory.c:4762 [inline] handle_pte_fault mm/memory.c:5029 [inline] __handle_mm_fault mm/memory.c:5171 [inline] handle_mm_fault+0x13fc/0x2fb0 mm/memory.c:5292 __do_page_fault arch/arm64/mm/fault.c:499 [inline] do_page_fault+0x4e4/0x98c arch/arm64/mm/fault.c:583 do_translation_fault+0x94/0xc8 arch/arm64/mm/fault.c:667 do_mem_abort+0x70/0x194 arch/arm64/mm/fault.c:804 el0_da+0x70/0x144 arch/arm64/kernel/entry-common.c:515 el0t_64_sync_handler+0x90/0xf0 arch/arm64/kernel/entry-common.c:658 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 other info that might help us debug this: Chain exists of: &sbi->lock --> &mm->mmap_lock --> sb_pagefaults#3 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(sb_pagefaults#3); lock(&mm->mmap_lock); lock(sb_pagefaults#3); lock(&sbi->lock); *** DEADLOCK *** 2 locks held by syz.4.878/8024: #0: ffff0000d2f89948 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline] #0: ffff0000d2f89948 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5320 [inline] #0: ffff0000d2f89948 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x38/0x2e0 mm/memory.c:5382 #1: ffff0000f7758558 (sb_pagefaults#3){.+.+}-{0:0}, at: do_page_mkwrite+0x13c/0x358 mm/memory.c:3009 stack backtrace: CPU: 1 PID: 8024 Comm: syz.4.878 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/26/2026 Call trace: dump_backtrace+0x1c0/0x1ec arch/arm64/kernel/stacktrace.c:158 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165 __dump_stack+0x30/0x40 lib/dump_stack.c:88 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106 dump_stack+0x1c/0x5c lib/dump_stack.c:113 print_circular_bug+0x148/0x1b0 kernel/locking/lockdep.c:2048 check_noncircular+0x264/0x2f8 kernel/locking/lockdep.c:2170 check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x2880/0x6800 kernel/locking/lockdep.c:5049 lock_acquire+0x20c/0x63c kernel/locking/lockdep.c:5662 __mutex_lock_common+0x190/0x1f60 kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799 reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27 reiserfs_dirty_inode+0xf0/0x224 fs/reiserfs/super.c:704 __mark_inode_dirty+0x2e8/0x11ac fs/fs-writeback.c:2449 generic_update_time fs/inode.c:1946 [inline] inode_update_time fs/inode.c:1959 [inline] __file_update_time+0x1f4/0x21c fs/inode.c:2147 file_update_time+0x270/0x2ec fs/inode.c:2178 filemap_page_mkwrite+0x31c/0x884 mm/filemap.c:3546 do_page_mkwrite+0x13c/0x358 mm/memory.c:3009 do_shared_fault mm/memory.c:4694 [inline] do_fault mm/memory.c:4762 [inline] handle_pte_fault mm/memory.c:5029 [inline] __handle_mm_fault mm/memory.c:5171 [inline] handle_mm_fault+0x13fc/0x2fb0 mm/memory.c:5292 __do_page_fault arch/arm64/mm/fault.c:499 [inline] do_page_fault+0x4e4/0x98c arch/arm64/mm/fault.c:583 do_translation_fault+0x94/0xc8 arch/arm64/mm/fault.c:667 do_mem_abort+0x70/0x194 arch/arm64/mm/fault.c:804 el0_da+0x70/0x144 arch/arm64/kernel/entry-common.c:515 el0t_64_sync_handler+0x90/0xf0 arch/arm64/kernel/entry-common.c:658 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585