============================================ WARNING: possible recursive locking detected 5.10.0-syzkaller #0 Not tainted -------------------------------------------- syz-executor.1/10069 is trying to acquire lock: ffff888012e3e398 (&hugetlbfs_i_mmap_rwsem_key){++++}-{3:3}, at: i_mmap_lock_write include/linux/fs.h:493 [inline] ffff888012e3e398 (&hugetlbfs_i_mmap_rwsem_key){++++}-{3:3}, at: unmap_ref_private mm/hugetlb.c:4019 [inline] ffff888012e3e398 (&hugetlbfs_i_mmap_rwsem_key){++++}-{3:3}, at: hugetlb_cow+0xedf/0x15f0 mm/hugetlb.c:4110 but task is already holding lock: ffff888012e3e398 (&hugetlbfs_i_mmap_rwsem_key){++++}-{3:3}, at: i_mmap_lock_read include/linux/fs.h:508 [inline] ffff888012e3e398 (&hugetlbfs_i_mmap_rwsem_key){++++}-{3:3}, at: hugetlb_fault+0x26c/0x2340 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.1/10069: #0: ffff888018e552d8 (&mm->mmap_lock#2){++++}-{3:3}, at: mmap_read_lock include/linux/mmap_lock.h:117 [inline] #0: ffff888018e552d8 (&mm->mmap_lock#2){++++}-{3:3}, at: process_vm_rw_single_vec mm/process_vm_access.c:104 [inline] #0: ffff888018e552d8 (&mm->mmap_lock#2){++++}-{3:3}, at: process_vm_rw_core.constprop.0+0x40f/0x990 mm/process_vm_access.c:215 #1: ffff888012e3e398 (&hugetlbfs_i_mmap_rwsem_key){++++}-{3:3}, at: i_mmap_lock_read include/linux/fs.h:508 [inline] #1: ffff888012e3e398 (&hugetlbfs_i_mmap_rwsem_key){++++}-{3:3}, at: hugetlb_fault+0x26c/0x2340 mm/hugetlb.c:4485 #2: ffff88814154a728 (&hugetlb_fault_mutex_table[i]){+.+.}-{3:3}, at: hugetlb_fault+0x368/0x2340 mm/hugetlb.c:4499 stack backtrace: CPU: 1 PID: 10069 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+0x15e/0x3b0 kernel/locking/lockdep.c:4832 lock_acquire kernel/locking/lockdep.c:5437 [inline] lock_acquire+0x29d/0x740 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+0xedf/0x15f0 mm/hugetlb.c:4110 hugetlb_fault+0x1561/0x2340 mm/hugetlb.c:4562 follow_hugetlb_page+0x3be/0x1030 mm/hugetlb.c:4816 __get_user_pages+0x5d8/0x1490 mm/gup.c:1041 __get_user_pages_locked mm/gup.c:1256 [inline] __get_user_pages_remote+0x18f/0x810 mm/gup.c:1723 pin_user_pages_remote+0x63/0x90 mm/gup.c:2791 process_vm_rw_single_vec mm/process_vm_access.c:105 [inline] process_vm_rw_core.constprop.0+0x445/0x990 mm/process_vm_access.c:215 process_vm_rw+0x29c/0x300 mm/process_vm_access.c:283 __do_sys_process_vm_writev mm/process_vm_access.c:303 [inline] __se_sys_process_vm_writev mm/process_vm_access.c:298 [inline] __x64_sys_process_vm_writev+0xdf/0x1b0 mm/process_vm_access.c:298 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:00007f3e27530c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000137 RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 000000000045e229 RDX: 0000000000000001 RSI: 0000000020000000 RDI: 0000000000000015 RBP: 000000000119bfd8 R08: 000000000000023a R09: 0000000000000000 R10: 0000000020121000 R11: 0000000000000246 R12: 000000000119bf8c R13: 00007ffc8137c72f R14: 00007f3e275319c0 R15: 000000000119bf8c