====================================================== WARNING: possible circular locking dependency detected 5.4.0-next-20191205-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.0/17350 is trying to acquire lock: ffff888063829500 (&rp->fetch_lock){+.+.}, at: mon_bin_vma_fault+0x73/0x2d0 drivers/usb/mon/mon_bin.c:1237 but task is already holding lock: ffff888065d7b718 (&mm->mmap_sem#2){++++}, at: __mm_populate+0x270/0x380 mm/gup.c:1263 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&mm->mmap_sem#2){++++}: __might_fault mm/memory.c:4544 [inline] __might_fault+0x15e/0x1e0 mm/memory.c:4529 _copy_to_user+0x30/0x160 lib/usercopy.c:26 copy_to_user include/linux/uaccess.h:152 [inline] mon_bin_read+0x329/0x640 drivers/usb/mon/mon_bin.c:825 do_loop_readv_writev fs/read_write.c:714 [inline] do_loop_readv_writev fs/read_write.c:701 [inline] do_iter_read+0x4a4/0x660 fs/read_write.c:935 vfs_readv+0xf0/0x160 fs/read_write.c:997 do_preadv+0x1c4/0x280 fs/read_write.c:1089 __do_sys_preadv fs/read_write.c:1139 [inline] __se_sys_preadv fs/read_write.c:1134 [inline] __x64_sys_preadv+0x9a/0xf0 fs/read_write.c:1134 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (&rp->fetch_lock){+.+.}: check_prev_add kernel/locking/lockdep.c:2476 [inline] check_prevs_add kernel/locking/lockdep.c:2581 [inline] validate_chain kernel/locking/lockdep.c:2971 [inline] __lock_acquire+0x2596/0x4a00 kernel/locking/lockdep.c:3955 lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4485 __mutex_lock_common kernel/locking/mutex.c:959 [inline] __mutex_lock+0x156/0x13c0 kernel/locking/mutex.c:1106 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1121 mon_bin_vma_fault+0x73/0x2d0 drivers/usb/mon/mon_bin.c:1237 __do_fault+0x111/0x540 mm/memory.c:3188 do_cow_fault mm/memory.c:3614 [inline] do_fault mm/memory.c:3716 [inline] handle_pte_fault mm/memory.c:3945 [inline] __handle_mm_fault+0x1258/0x3da0 mm/memory.c:4075 handle_mm_fault+0x3b2/0xa50 mm/memory.c:4112 faultin_page mm/gup.c:640 [inline] __get_user_pages+0x7b2/0x1ac0 mm/gup.c:851 populate_vma_page_range+0x20d/0x2a0 mm/gup.c:1235 __mm_populate+0x204/0x380 mm/gup.c:1283 mm_populate include/linux/mm.h:2347 [inline] vm_mmap_pgoff+0x213/0x230 mm/util.c:511 ksys_mmap_pgoff+0x4aa/0x630 mm/mmap.c:1607 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:100 [inline] __se_sys_mmap arch/x86/kernel/sys_x86_64.c:91 [inline] __x64_sys_mmap+0xe9/0x1b0 arch/x86/kernel/sys_x86_64.c:91 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&mm->mmap_sem#2); lock(&rp->fetch_lock); lock(&mm->mmap_sem#2); lock(&rp->fetch_lock); *** DEADLOCK *** 1 lock held by syz-executor.0/17350: #0: ffff888065d7b718 (&mm->mmap_sem#2){++++}, at: __mm_populate+0x270/0x380 mm/gup.c:1263 stack backtrace: CPU: 0 PID: 17350 Comm: syz-executor.0 Not tainted 5.4.0-next-20191205-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 print_circular_bug.isra.0.cold+0x163/0x172 kernel/locking/lockdep.c:1685 check_noncircular+0x32e/0x3e0 kernel/locking/lockdep.c:1809 check_prev_add kernel/locking/lockdep.c:2476 [inline] check_prevs_add kernel/locking/lockdep.c:2581 [inline] validate_chain kernel/locking/lockdep.c:2971 [inline] __lock_acquire+0x2596/0x4a00 kernel/locking/lockdep.c:3955 lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4485 __mutex_lock_common kernel/locking/mutex.c:959 [inline] __mutex_lock+0x156/0x13c0 kernel/locking/mutex.c:1106 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1121 mon_bin_vma_fault+0x73/0x2d0 drivers/usb/mon/mon_bin.c:1237 __do_fault+0x111/0x540 mm/memory.c:3188 do_cow_fault mm/memory.c:3614 [inline] do_fault mm/memory.c:3716 [inline] handle_pte_fault mm/memory.c:3945 [inline] __handle_mm_fault+0x1258/0x3da0 mm/memory.c:4075 handle_mm_fault+0x3b2/0xa50 mm/memory.c:4112 faultin_page mm/gup.c:640 [inline] __get_user_pages+0x7b2/0x1ac0 mm/gup.c:851 populate_vma_page_range+0x20d/0x2a0 mm/gup.c:1235 __mm_populate+0x204/0x380 mm/gup.c:1283 mm_populate include/linux/mm.h:2347 [inline] vm_mmap_pgoff+0x213/0x230 mm/util.c:511 ksys_mmap_pgoff+0x4aa/0x630 mm/mmap.c:1607 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:100 [inline] __se_sys_mmap arch/x86/kernel/sys_x86_64.c:91 [inline] __x64_sys_mmap+0xe9/0x1b0 arch/x86/kernel/sys_x86_64.c:91 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45a679 Code: ad b6 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f2fef50ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 000000000045a679 RDX: 0000000001000002 RSI: 0000000000400300 RDI: 0000000020a05000 RBP: 000000000075bf20 R08: 0000000000000003 R09: 0000000000000000 R10: 0000000000008012 R11: 0000000000000246 R12: 00007f2fef50f6d4 R13: 00000000004c7861 R14: 00000000004de5a8 R15: 00000000ffffffff