============================================ WARNING: possible recursive locking detected 5.10.0-syzkaller #0 Not tainted -------------------------------------------- syz-executor.1/11065 is trying to acquire lock: ffff888015879698 (&hugetlbfs_i_mmap_rwsem_key){++++}-{3:3}, at: i_mmap_lock_write include/linux/fs.h:493 [inline] ffff888015879698 (&hugetlbfs_i_mmap_rwsem_key){++++}-{3:3}, at: unmap_ref_private mm/hugetlb.c:4019 [inline] ffff888015879698 (&hugetlbfs_i_mmap_rwsem_key){++++}-{3:3}, at: hugetlb_cow+0xf55/0x16c0 mm/hugetlb.c:4110 but task is already holding lock: ffff888015879698 (&hugetlbfs_i_mmap_rwsem_key){++++}-{3:3}, at: i_mmap_lock_read include/linux/fs.h:508 [inline] ffff888015879698 (&hugetlbfs_i_mmap_rwsem_key){++++}-{3:3}, at: hugetlb_fault+0x2c1/0x24f0 mm/hugetlb.c:4485 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&hugetlbfs_i_mmap_rwsem_key); lock(&hugetlbfs_i_mmap_rwsem_key); *** DEADLOCK *** May be due to missing lock nesting notation 3 locks held by syz-executor.1/11065: #0: ffff888019331d58 (&mm->mmap_lock#2){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline] #0: ffff888019331d58 (&mm->mmap_lock#2){++++}-{3:3}, at: do_user_addr_fault+0x25f/0xc60 arch/x86/mm/fault.c:1334 #1: ffff888015879698 (&hugetlbfs_i_mmap_rwsem_key){++++}-{3:3}, at: i_mmap_lock_read include/linux/fs.h:508 [inline] #1: ffff888015879698 (&hugetlbfs_i_mmap_rwsem_key){++++}-{3:3}, at: hugetlb_fault+0x2c1/0x24f0 mm/hugetlb.c:4485 #2: ffff888141548608 (&hugetlb_fault_mutex_table[i]){+.+.}-{3:3}, at: hugetlb_fault+0x433/0x24f0 mm/hugetlb.c:4499 stack backtrace: CPU: 0 PID: 11065 Comm: syz-executor.1 Not tainted 5.10.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:120 print_deadlock_bug kernel/locking/lockdep.c:2761 [inline] check_deadlock kernel/locking/lockdep.c:2804 [inline] validate_chain kernel/locking/lockdep.c:3595 [inline] __lock_acquire.cold+0x115/0x3e6 kernel/locking/lockdep.c:4832 lock_acquire kernel/locking/lockdep.c:5437 [inline] lock_acquire+0x29d/0x750 kernel/locking/lockdep.c:5402 down_write+0x8d/0x150 kernel/locking/rwsem.c:1406 i_mmap_lock_write include/linux/fs.h:493 [inline] unmap_ref_private mm/hugetlb.c:4019 [inline] hugetlb_cow+0xf55/0x16c0 mm/hugetlb.c:4110 hugetlb_fault+0x1708/0x24f0 mm/hugetlb.c:4562 handle_mm_fault+0x11b8/0x5760 mm/memory.c:4616 do_user_addr_fault+0x458/0xc60 arch/x86/mm/fault.c:1393 handle_page_fault arch/x86/mm/fault.c:1450 [inline] exc_page_fault+0x9e/0x180 arch/x86/mm/fault.c:1506 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:580 RIP: 0010:__put_user_nocheck_8+0x3/0x21 Code: 00 00 48 39 d9 73 34 0f 1f 00 89 01 31 c9 0f 1f 00 c3 66 0f 1f 44 00 00 48 bb f9 ef ff ff ff 7f 00 00 48 39 d9 73 14 0f 1f 00 <48> 89 01 31 c9 0f 1f 00 c3 0f 1f 44 00 00 0f 1f 00 b9 f2 ff ff ff RSP: 0018:ffffc90007d9fe98 EFLAGS: 00010297 RAX: 00007f3430b6e9d0 RBX: 00007fffffffeff9 RCX: 0000000020000080 RDX: 1ffff11003ecd776 RSI: ffffffff8148e71c RDI: ffff88801f66bbb0 RBP: 1ffff92000fb3fd6 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000028 R12: 0000000000000000 R13: 0000000020000080 R14: 0000000000000000 R15: ffffffffffffffda prctl_get_tid_address kernel/sys.c:2244 [inline] __do_sys_prctl+0x8c5/0x1040 kernel/sys.c:2431 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45e229 Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f3430b6dc68 EFLAGS: 00000246 ORIG_RAX: 000000000000009d RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 000000000045e229 RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000028 RBP: 000000000119bfb8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119bf8c R13: 00000000016afb6f R14: 00007f3430b6e9c0 R15: 000000000119bf8c