====================================================== WARNING: possible circular locking dependency detected 5.4.0-rc3-next-20191017 #0 Not tainted ------------------------------------------------------ syz-executor.0/8651 is trying to acquire lock: ffff8880a78ce8d8 (&mm->mmap_sem#2){++++}, at: __might_fault+0xfb/0x1e0 mm/memory.c:4471 but task is already holding lock: ffff8880a4e40d00 (&rp->fetch_lock){+.+.}, at: mon_bin_fetch+0x37/0x340 drivers/usb/mon/mon_bin.c:909 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&rp->fetch_lock){+.+.}: __mutex_lock_common kernel/locking/mutex.c:956 [inline] __mutex_lock+0x156/0x13c0 kernel/locking/mutex.c:1103 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118 mon_bin_vma_fault+0x73/0x2d0 drivers/usb/mon/mon_bin.c:1237 __do_fault+0x111/0x540 mm/memory.c:3114 do_read_fault mm/memory.c:3511 [inline] do_fault mm/memory.c:3640 [inline] handle_pte_fault mm/memory.c:3871 [inline] __handle_mm_fault+0x2d49/0x3fd0 mm/memory.c:3995 handle_mm_fault+0x3b2/0xa90 mm/memory.c:4032 faultin_page mm/gup.c:640 [inline] __get_user_pages+0x7cf/0x1b20 mm/gup.c:845 populate_vma_page_range+0x20d/0x2a0 mm/gup.c:1223 __mm_populate+0x204/0x380 mm/gup.c:1271 mm_populate include/linux/mm.h:2370 [inline] vm_mmap_pgoff+0x213/0x230 mm/util.c:511 ksys_mmap_pgoff+0x4aa/0x630 mm/mmap.c:1604 __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/0x760 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (&mm->mmap_sem#2){++++}: 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:4487 __might_fault mm/memory.c:4472 [inline] __might_fault+0x15e/0x1e0 mm/memory.c:4457 mon_bin_fetch+0x26f/0x340 drivers/usb/mon/mon_bin.c:928 mon_bin_ioctl+0x21e/0xc80 drivers/usb/mon/mon_bin.c:1091 vfs_ioctl fs/ioctl.c:47 [inline] file_ioctl fs/ioctl.c:539 [inline] do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:726 ksys_ioctl+0xab/0xd0 fs/ioctl.c:743 __do_sys_ioctl fs/ioctl.c:750 [inline] __se_sys_ioctl fs/ioctl.c:748 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:748 do_syscall_64+0xfa/0x760 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(&rp->fetch_lock); lock(&mm->mmap_sem#2); lock(&rp->fetch_lock); lock(&mm->mmap_sem#2); *** DEADLOCK *** 1 lock held by syz-executor.0/8651: #0: ffff8880a4e40d00 (&rp->fetch_lock){+.+.}, at: mon_bin_fetch+0x37/0x340 drivers/usb/mon/mon_bin.c:909 stack backtrace: CPU: 0 PID: 8651 Comm: syz-executor.0 Not tainted 5.4.0-rc3-next-20191017 #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+0x172/0x1f0 lib/dump_stack.c:113 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:4487 __might_fault mm/memory.c:4472 [inline] __might_fault+0x15e/0x1e0 mm/memory.c:4457 mon_bin_fetch+0x26f/0x340 drivers/usb/mon/mon_bin.c:928 mon_bin_ioctl+0x21e/0xc80 drivers/usb/mon/mon_bin.c:1091 vfs_ioctl fs/ioctl.c:47 [inline] file_ioctl fs/ioctl.c:539 [inline] do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:726 ksys_ioctl+0xab/0xd0 fs/ioctl.c:743 __do_sys_ioctl fs/ioctl.c:750 [inline] __se_sys_ioctl fs/ioctl.c:748 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:748 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459a59 Code: fd b7 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fcac0611c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459a59 RDX: 0000000020000280 RSI: 00000000c0109207 RDI: 0000000000000003 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fcac06126d4 R13: 00000000004c3357 R14: 00000000004d7088 R15: 00000000ffffffff