======================================================
WARNING: possible circular locking dependency detected
5.4.0-rc2+ #0 Not tainted
------------------------------------------------------
syz-executor.2/19455 is trying to acquire lock:
ffff88808250ea58 (&mm->mmap_sem#2){++++}, at: __might_fault+0xd2/0x160 mm/memory.c:4449

but task is already holding lock:
ffff8880a9beed00 (&rp->fetch_lock){+.+.}, at: mon_bin_read+0x5c/0x7b0 drivers/usb/mon/mon_bin.c:813

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&rp->fetch_lock){+.+.}:
       lock_acquire+0x158/0x250 kernel/locking/lockdep.c:4487
       __mutex_lock_common+0x14c/0x2e20 kernel/locking/mutex.c:956
       __mutex_lock kernel/locking/mutex.c:1103 [inline]
       mutex_lock_nested+0x1b/0x30 kernel/locking/mutex.c:1118
       mon_bin_vma_fault+0x6d/0x260 drivers/usb/mon/mon_bin.c:1237
       __do_fault+0x144/0x3d0 mm/memory.c:3092
       do_read_fault mm/memory.c:3489 [inline]
       do_fault mm/memory.c:3618 [inline]
       handle_pte_fault mm/memory.c:3849 [inline]
       __handle_mm_fault mm/memory.c:3973 [inline]
       handle_mm_fault+0x42f1/0x5ff0 mm/memory.c:4010
       faultin_page mm/gup.c:640 [inline]
       __get_user_pages+0x1002/0x1610 mm/gup.c:845
       populate_vma_page_range+0x1fd/0x250 mm/gup.c:1223
       __mm_populate+0x278/0x3d0 mm/gup.c:1271
       mm_populate include/linux/mm.h:2362 [inline]
       vm_mmap_pgoff+0x1a0/0x1d0 mm/util.c:501
       ksys_mmap_pgoff+0x46b/0x560 mm/mmap.c:1629
       __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+0x103/0x120 arch/x86/kernel/sys_x86_64.c:91
       do_syscall_64+0xf7/0x1c0 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+0x161e/0x7bc0 kernel/locking/lockdep.c:2971
       __lock_acquire+0xc75/0x1be0 kernel/locking/lockdep.c:3955
       lock_acquire+0x158/0x250 kernel/locking/lockdep.c:4487
       __might_fault+0xf5/0x160 mm/memory.c:4450
       _copy_to_user+0x2c/0x150 lib/usercopy.c:26
       copy_to_user include/linux/uaccess.h:152 [inline]
       mon_bin_read+0x1ac/0x7b0 drivers/usb/mon/mon_bin.c:825
       __vfs_read+0xb8/0x730 fs/read_write.c:425
       vfs_read+0x1dd/0x420 fs/read_write.c:461
       ksys_read+0x117/0x220 fs/read_write.c:587
       __do_sys_read fs/read_write.c:597 [inline]
       __se_sys_read fs/read_write.c:595 [inline]
       __x64_sys_read+0x7b/0x90 fs/read_write.c:595
       do_syscall_64+0xf7/0x1c0 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.2/19455:
 #0: ffff8880a9beed00 (&rp->fetch_lock){+.+.}, at: mon_bin_read+0x5c/0x7b0 drivers/usb/mon/mon_bin.c:813

stack backtrace:
CPU: 0 PID: 19455 Comm: syz-executor.2 Not tainted 5.4.0-rc2+ #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+0x1d8/0x2f8 lib/dump_stack.c:113
 print_circular_bug+0xc2d/0xe60 kernel/locking/lockdep.c:1685
 check_noncircular+0x206/0x3a0 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+0x161e/0x7bc0 kernel/locking/lockdep.c:2971
 __lock_acquire+0xc75/0x1be0 kernel/locking/lockdep.c:3955
 lock_acquire+0x158/0x250 kernel/locking/lockdep.c:4487
 __might_fault+0xf5/0x160 mm/memory.c:4450
 _copy_to_user+0x2c/0x150 lib/usercopy.c:26
 copy_to_user include/linux/uaccess.h:152 [inline]
 mon_bin_read+0x1ac/0x7b0 drivers/usb/mon/mon_bin.c:825
 __vfs_read+0xb8/0x730 fs/read_write.c:425
 vfs_read+0x1dd/0x420 fs/read_write.c:461
 ksys_read+0x117/0x220 fs/read_write.c:587
 __do_sys_read fs/read_write.c:597 [inline]
 __se_sys_read fs/read_write.c:595 [inline]
 __x64_sys_read+0x7b/0x90 fs/read_write.c:595
 do_syscall_64+0xf7/0x1c0 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:00007fe29e3b9c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459a59
RDX: 0000000000000250 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe29e3ba6d4
R13: 00000000004c712b R14: 00000000004dc9f0 R15: 00000000ffffffff