====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.4.629/12387 is trying to acquire lock: ffff8880675242f8 (mapping.invalidate_lock#4){++++}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:1092 [inline] ffff8880675242f8 (mapping.invalidate_lock#4){++++}-{4:4}, at: filemap_fault+0x66f/0x12f0 mm/filemap.c:3537 but task is already holding lock: ffff8880371e4370 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock include/linux/mmap_lock.h:410 [inline] ffff8880371e4370 (&mm->mmap_lock){++++}-{4:4}, at: get_mmap_lock_carefully mm/mmap_lock.c:390 [inline] ffff8880371e4370 (&mm->mmap_lock){++++}-{4:4}, at: lock_mm_and_find_vma+0x36/0x340 mm/mmap_lock.c:450 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&mm->mmap_lock){++++}-{4:4}: __might_fault+0xcb/0x130 mm/memory.c:7177 _inline_copy_to_user include/linux/uaccess.h:201 [inline] _copy_to_user+0x2c/0xb0 lib/usercopy.c:26 copy_to_user include/linux/uaccess.h:236 [inline] fiemap_fill_next_extent+0x1dd/0x3c0 fs/ioctl.c:144 ni_fiemap+0x9a5/0xca0 fs/ntfs3/frecord.c:2009 ntfs_fiemap+0x11d/0x1a0 fs/ntfs3/file.c:1419 ioctl_fiemap fs/ioctl.c:219 [inline] do_vfs_ioctl+0x126f/0x1540 fs/ioctl.c:531 __do_sys_ioctl fs/ioctl.c:595 [inline] __se_sys_ioctl+0x82/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&ni->ni_lock/5){+.+.}-{4:4}: __mutex_lock_common kernel/locking/rtmutex_api.c:533 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:552 ni_lock fs/ntfs3/ntfs_fs.h:1127 [inline] ntfs_fallocate+0x7f3/0x1140 fs/ntfs3/file.c:689 vfs_fallocate+0x672/0x7f0 fs/open.c:339 ksys_fallocate fs/open.c:363 [inline] __do_sys_fallocate fs/open.c:368 [inline] __se_sys_fallocate fs/open.c:366 [inline] __x64_sys_fallocate+0xc0/0x110 fs/open.c:366 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (mapping.invalidate_lock#4){++++}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868 down_read+0x97/0x200 kernel/locking/rwsem.c:1537 filemap_invalidate_lock_shared include/linux/fs.h:1092 [inline] filemap_fault+0x66f/0x12f0 mm/filemap.c:3537 __do_fault+0x138/0x390 mm/memory.c:5323 do_read_fault mm/memory.c:5758 [inline] do_fault mm/memory.c:5892 [inline] do_pte_missing+0x18d3/0x2e60 mm/memory.c:4404 handle_pte_fault mm/memory.c:6276 [inline] __handle_mm_fault mm/memory.c:6414 [inline] handle_mm_fault+0xd0a/0x13c0 mm/memory.c:6583 do_user_addr_fault+0x75b/0x1360 arch/x86/mm/fault.c:1385 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 do_strnlen_user lib/strnlen_user.c:34 [inline] strnlen_user+0x4b/0x150 lib/strnlen_user.c:103 strndup_user+0x1f/0xd0 mm/util.c:272 copy_mount_string fs/namespace.c:3930 [inline] __do_sys_mount fs/namespace.c:4209 [inline] __se_sys_mount+0x9d/0x420 fs/namespace.c:4201 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 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: mapping.invalidate_lock#4 --> &ni->ni_lock/5 --> &mm->mmap_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(&mm->mmap_lock); lock(&ni->ni_lock/5); lock(&mm->mmap_lock); rlock(mapping.invalidate_lock#4); *** DEADLOCK *** 1 lock held by syz.4.629/12387: #0: ffff8880371e4370 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock include/linux/mmap_lock.h:410 [inline] #0: ffff8880371e4370 (&mm->mmap_lock){++++}-{4:4}, at: get_mmap_lock_carefully mm/mmap_lock.c:390 [inline] #0: ffff8880371e4370 (&mm->mmap_lock){++++}-{4:4}, at: lock_mm_and_find_vma+0x36/0x340 mm/mmap_lock.c:450 stack backtrace: CPU: 0 UID: 0 PID: 12387 Comm: syz.4.629 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043 check_noncircular+0x12e/0x150 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 kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868 down_read+0x97/0x200 kernel/locking/rwsem.c:1537 filemap_invalidate_lock_shared include/linux/fs.h:1092 [inline] filemap_fault+0x66f/0x12f0 mm/filemap.c:3537 __do_fault+0x138/0x390 mm/memory.c:5323 do_read_fault mm/memory.c:5758 [inline] do_fault mm/memory.c:5892 [inline] do_pte_missing+0x18d3/0x2e60 mm/memory.c:4404 handle_pte_fault mm/memory.c:6276 [inline] __handle_mm_fault mm/memory.c:6414 [inline] handle_mm_fault+0xd0a/0x13c0 mm/memory.c:6583 do_user_addr_fault+0x75b/0x1360 arch/x86/mm/fault.c:1385 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0010:do_strnlen_user lib/strnlen_user.c:37 [inline] RIP: 0010:strnlen_user+0x4b/0x150 lib/strnlen_user.c:103 Code: de e8 09 08 f7 fc 48 85 db 0f 8e f6 00 00 00 48 b8 00 f0 ff ff ff 7f 00 00 49 39 c6 4c 0f 47 f0 0f 01 cb 4c 89 f0 48 83 e0 f8 <48> 8b 28 45 89 f5 41 83 e5 07 42 8d 0c ed 00 00 00 00 48 c7 c0 ff RSP: 0018:ffffc900068cfda0 EFLAGS: 00050206 RAX: 0000200000001900 RBX: 0000000000001000 RCX: ffff88802d8e0000 RDX: 0000000000000002 RSI: 0000000000001000 RDI: 0000000000000001 RBP: ffffc900068cfee0 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: fffffbfff1e8fbcf R12: 0000000000000000 R13: 1ffff92000d19fc8 R14: 0000200000001900 R15: 0000000000001000 strndup_user+0x1f/0xd0 mm/util.c:272 copy_mount_string fs/namespace.c:3930 [inline] __do_sys_mount fs/namespace.c:4209 [inline] __se_sys_mount+0x9d/0x420 fs/namespace.c:4201 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5e6fe7aeb9 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:00007f5e6e0d6028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f5e700f5fa0 RCX: 00007f5e6fe7aeb9 RDX: 0000200000001900 RSI: 00002000000018c0 RDI: 0000200000001880 RBP: 00007f5e6fee8c1f R08: 0000200000001940 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5e700f6038 R14: 00007f5e700f5fa0 R15: 00007ffc6ada8708 ---------------- Code disassembly (best guess): 0: de e8 fsubrp %st,%st(0) 2: 09 08 or %ecx,(%rax) 4: f7 fc idiv %esp 6: 48 85 db test %rbx,%rbx 9: 0f 8e f6 00 00 00 jle 0x105 f: 48 b8 00 f0 ff ff ff movabs $0x7ffffffff000,%rax 16: 7f 00 00 19: 49 39 c6 cmp %rax,%r14 1c: 4c 0f 47 f0 cmova %rax,%r14 20: 0f 01 cb stac 23: 4c 89 f0 mov %r14,%rax 26: 48 83 e0 f8 and $0xfffffffffffffff8,%rax * 2a: 48 8b 28 mov (%rax),%rbp <-- trapping instruction 2d: 45 89 f5 mov %r14d,%r13d 30: 41 83 e5 07 and $0x7,%r13d 34: 42 8d 0c ed 00 00 00 lea 0x0(,%r13,8),%ecx 3b: 00 3c: 48 rex.W 3d: c7 .byte 0xc7 3e: c0 .byte 0xc0 3f: ff .byte 0xff