====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.0.17/5959 is trying to acquire lock: ffff888167d5c918 (&hugetlbfs_i_mmap_rwsem_key){+.+.}-{4:4}, at: i_mmap_lock_write include/linux/fs.h:548 [inline] ffff888167d5c918 (&hugetlbfs_i_mmap_rwsem_key){+.+.}-{4:4}, at: move_hugetlb_page_tables+0x5a5/0x1560 mm/hugetlb.c:5114 but task is already holding lock: ffff8881b5f35e78 (&vma_lock->rw_sema){+.+.}-{4:4}, at: hugetlb_vma_lock_write mm/hugetlb.c:-1 [inline] ffff8881b5f35e78 (&vma_lock->rw_sema){+.+.}-{4:4}, at: move_hugetlb_page_tables+0x589/0x1560 mm/hugetlb.c:5113 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&vma_lock->rw_sema){+.+.}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 down_write+0x96/0x1f0 kernel/locking/rwsem.c:1590 hugetlb_zap_begin include/linux/hugetlb.h:257 [inline] unmap_vmas+0x23d/0x580 mm/memory.c:2098 vms_clear_ptes+0x353/0x530 mm/vma.c:1231 vms_complete_munmap_vmas+0x206/0x8a0 mm/vma.c:1280 do_vmi_align_munmap+0x364/0x440 mm/vma.c:1539 do_vmi_munmap+0x253/0x2e0 mm/vma.c:1587 shrink_vma mm/mremap.c:1340 [inline] mremap_to+0x21e/0x790 mm/mremap.c:1394 do_mremap mm/mremap.c:1940 [inline] __do_sys_mremap mm/mremap.c:1996 [inline] __se_sys_mremap+0xd45/0xfb0 mm/mremap.c:1964 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 (&hugetlbfs_i_mmap_rwsem_key){+.+.}-{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 i_mmap_lock_write include/linux/fs.h:548 [inline] move_hugetlb_page_tables+0x5a5/0x1560 mm/hugetlb.c:5114 move_page_tables+0x35c/0x1c80 mm/mremap.c:806 copy_vma_and_data mm/mremap.c:1211 [inline] move_vma+0x942/0x1820 mm/mremap.c:1291 mremap_to+0x6ce/0x790 mm/mremap.c:1415 do_mremap mm/mremap.c:1940 [inline] __do_sys_mremap mm/mremap.c:1996 [inline] __se_sys_mremap+0xd45/0xfb0 mm/mremap.c:1964 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: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&vma_lock->rw_sema); lock(&hugetlbfs_i_mmap_rwsem_key); lock(&vma_lock->rw_sema); lock(&hugetlbfs_i_mmap_rwsem_key); *** DEADLOCK *** 2 locks held by syz.0.17/5959: #0: ffff888172d8d7e0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:327 [inline] #0: ffff888172d8d7e0 (&mm->mmap_lock){++++}-{4:4}, at: do_mremap mm/mremap.c:1927 [inline] #0: ffff888172d8d7e0 (&mm->mmap_lock){++++}-{4:4}, at: __do_sys_mremap mm/mremap.c:1996 [inline] #0: ffff888172d8d7e0 (&mm->mmap_lock){++++}-{4:4}, at: __se_sys_mremap+0x42e/0xfb0 mm/mremap.c:1964 #1: ffff8881b5f35e78 (&vma_lock->rw_sema){+.+.}-{4:4}, at: hugetlb_vma_lock_write mm/hugetlb.c:-1 [inline] #1: ffff8881b5f35e78 (&vma_lock->rw_sema){+.+.}-{4:4}, at: move_hugetlb_page_tables+0x589/0x1560 mm/hugetlb.c:5113 stack backtrace: CPU: 1 UID: 0 PID: 5959 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 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 i_mmap_lock_write include/linux/fs.h:548 [inline] move_hugetlb_page_tables+0x5a5/0x1560 mm/hugetlb.c:5114 move_page_tables+0x35c/0x1c80 mm/mremap.c:806 copy_vma_and_data mm/mremap.c:1211 [inline] move_vma+0x942/0x1820 mm/mremap.c:1291 mremap_to+0x6ce/0x790 mm/mremap.c:1415 do_mremap mm/mremap.c:1940 [inline] __do_sys_mremap mm/mremap.c:1996 [inline] __se_sys_mremap+0xd45/0xfb0 mm/mremap.c:1964 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: 0033:0x7f043598efc9 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:00007ffe808cfc08 EFLAGS: 00000246 ORIG_RAX: 0000000000000019 RAX: ffffffffffffffda RBX: 00007f0435be5fa0 RCX: 00007f043598efc9 RDX: 0000000000400000 RSI: 0000000000c00000 RDI: 0000200000000000 RBP: 00007f0435a11f91 R08: 0000200000c00000 R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f0435be5fa0 R14: 00007f0435be5fa0 R15: 0000000000000005