====================================================== WARNING: possible circular locking dependency detected 5.0.0-next-20190306 #4 Not tainted ------------------------------------------------------ syz-executor629/7918 is trying to acquire lock: 000000002417d4ab (&rp->fetch_lock){+.+.}, at: mon_bin_vma_fault+0x73/0x2d0 drivers/usb/mon/mon_bin.c:1237 but task is already holding lock: 00000000d5099c6a (&mm->mmap_sem){++++}, at: __mm_populate+0x270/0x380 mm/gup.c:1427 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&mm->mmap_sem){++++}: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4202 __might_fault mm/memory.c:4406 [inline] __might_fault+0x15e/0x1e0 mm/memory.c:4391 _copy_to_user+0x30/0x120 lib/usercopy.c:25 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:700 [inline] do_loop_readv_writev fs/read_write.c:687 [inline] do_iter_read+0x4a9/0x660 fs/read_write.c:921 vfs_readv+0xf0/0x160 fs/read_write.c:983 do_preadv+0x1c4/0x280 fs/read_write.c:1067 __do_sys_preadv fs/read_write.c:1117 [inline] __se_sys_preadv fs/read_write.c:1112 [inline] __x64_sys_preadv+0x9a/0xf0 fs/read_write.c:1112 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (&rp->fetch_lock){+.+.}: check_prevs_add kernel/locking/lockdep.c:2324 [inline] validate_chain kernel/locking/lockdep.c:2705 [inline] __lock_acquire+0x239c/0x3fb0 kernel/locking/lockdep.c:3692 lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4202 __mutex_lock_common kernel/locking/mutex.c:925 [inline] __mutex_lock+0xf7/0x1310 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 mon_bin_vma_fault+0x73/0x2d0 drivers/usb/mon/mon_bin.c:1237 __do_fault+0x116/0x4e0 mm/memory.c:3039 do_cow_fault mm/memory.c:3478 [inline] do_fault mm/memory.c:3580 [inline] handle_pte_fault mm/memory.c:3809 [inline] __handle_mm_fault+0xf6c/0x3ec0 mm/memory.c:3933 handle_mm_fault+0x43f/0xb30 mm/memory.c:3970 faultin_page mm/gup.c:538 [inline] __get_user_pages+0x7b6/0x1a40 mm/gup.c:741 populate_vma_page_range+0x20d/0x2a0 mm/gup.c:1399 __mm_populate+0x204/0x380 mm/gup.c:1447 mm_populate include/linux/mm.h:2383 [inline] vm_mmap_pgoff+0x213/0x230 mm/util.c:367 ksys_mmap_pgoff+0x4aa/0x630 mm/mmap.c:1609 __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+0x103/0x610 arch/x86/entry/common.c:290 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); lock(&rp->fetch_lock); lock(&mm->mmap_sem); lock(&rp->fetch_lock); *** DEADLOCK *** 1 lock held by syz-executor629/7918: #0: 00000000d5099c6a (&mm->mmap_sem){++++}, at: __mm_populate+0x270/0x380 mm/gup.c:1427 stack backtrace: CPU: 1 PID: 7918 Comm: syz-executor629 Not tainted 5.0.0-next-20190306 #4 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+0x172/0x1f0 lib/dump_stack.c:113 print_circular_bug.isra.0.cold+0x1cc/0x28f kernel/locking/lockdep.c:1562 check_prev_add.constprop.0+0xf11/0x23c0 kernel/locking/lockdep.c:2211 check_prevs_add kernel/locking/lockdep.c:2324 [inline] validate_chain kernel/locking/lockdep.c:2705 [inline] __lock_acquire+0x239c/0x3fb0 kernel/locking/lockdep.c:3692 lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4202 __mutex_lock_common kernel/locking/mutex.c:925 [inline] __mutex_lock+0xf7/0x1310 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 mon_bin_vma_fault+0x73/0x2d0 drivers/usb/mon/mon_bin.c:1237 __do_fault+0x116/0x4e0 mm/memory.c:3039 do_cow_fault mm/memory.c:3478 [inline] do_fault mm/memory.c:3580 [inline] handle_pte_fault mm/memory.c:3809 [inline] __handle_mm_fault+0xf6c/0x3ec0 mm/memory.c:3933 handle_mm_fault+0x43f/0xb30 mm/memory.c:3970 faultin_page mm/gup.c:538 [inline] __get_user_pages+0x7b6/0x1a40 mm/gup.c:741 populate_vma_page_range+0x20d/0x2a0 mm/gup.c:1399 __mm_populate+0x204/0x380 mm/gup.c:1447 mm_populate include/linux/mm.h:2383 [inline] vm_mmap_pgoff+0x213/0x230 mm/util.c:367 ksys_mmap_pgoff+0x4aa/0x630 mm/mmap.c:1609 __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+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x449669 Code: e8 9c b8 02 00 48 83 c4 18 c3 0f 1f 80 00 00 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 0f 83 ab d6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f46d5104cd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00000000006dac38 RCX: 0000000000449669 RDX: 0000000000000013 RSI: 0000000000400000 RDI: 0000000020a05000 RBP: 00000000006dac30 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000008012 R11: 0000000000000246 R12: 00000000006dac3c R13: 00007fffbe74f71f R14: 00007f46d51059c0 R15: 20c49ba5e353f7cf