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------------[ cut here ]------------
downgrading a read lock
WARNING: CPU: 0 PID: 13705 at kernel/locking/lockdep.c:3556 __lock_downgrade kernel/locking/lockdep.c:3556 [inline]
WARNING: CPU: 0 PID: 13705 at kernel/locking/lockdep.c:3556 lock_downgrade+0x4d7/0x900 kernel/locking/lockdep.c:3819
Kernel panic - not syncing: panic_on_warn set ...
kobject: 'loop3' (00000000487d4b74): kobject_uevent_env
CPU: 0 PID: 13705 Comm: modprobe Not tainted 4.20.0-rc4+ #356
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+0x244/0x39d lib/dump_stack.c:113
 panic+0x2ad/0x55c kernel/panic.c:188
 __warn.cold.8+0x20/0x45 kernel/panic.c:540
 report_bug+0x254/0x2d0 lib/bug.c:186
kobject: 'loop3' (00000000487d4b74): fill_kobj_path: path = '/devices/virtual/block/loop3'
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271
 do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:290
kobject: 'loop3' (00000000487d4b74): kobject_uevent_env
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:969
RIP: 0010:__lock_downgrade kernel/locking/lockdep.c:3556 [inline]
RIP: 0010:lock_downgrade+0x4d7/0x900 kernel/locking/lockdep.c:3819
Code: 00 00 fc ff df 41 c6 44 05 00 f8 e9 1b ff ff ff 48 c7 c7 60 68 2b 88 4c 89 9d 58 ff ff ff 48 89 85 60 ff ff ff e8 d9 1f e7 ff <0f> 0b 48 8b 85 60 ff ff ff 4c 8d 4d d8 4c 89 e9 48 ba 00 00 00 00
RSP: 0018:ffff8881d7ef7b70 EFLAGS: 00010086
RAX: 0000000000000000 RBX: 1ffff1103afdef74 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8165eaf5 RDI: 0000000000000006
RBP: ffff8881d7ef7c28 R08: ffff88818779c280 R09: fffffbfff12b2254
R10: fffffbfff12b2254 R11: ffffffff895912a3 R12: ffffffff8b0f77a0
R13: ffff8881d7ef7bc0 R14: 0000000000000001 R15: ffff88818779c280
WARNING: syz-executor2/13706 still has locks held!
 downgrade_write+0x76/0x270 kernel/locking/rwsem.c:147
kobject: 'loop3' (00000000487d4b74): fill_kobj_path: path = '/devices/virtual/block/loop3'
 __do_munmap+0xcd8/0xf80 mm/mmap.c:2812
 __vm_munmap+0x138/0x1f0 mm/mmap.c:2837
 __do_sys_munmap mm/mmap.c:2862 [inline]
 __se_sys_munmap mm/mmap.c:2859 [inline]
 __x64_sys_munmap+0x65/0x80 mm/mmap.c:2859
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
4.20.0-rc4+ #356 Not tainted
------------------------------------
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
kobject: 'loop1' (00000000690fce5f): kobject_uevent_env
RIP: 0033:0x7f14c816b417
Code: f0 ff ff 73 01 c3 48 8d 0d 8a ad 20 00 31 d2 48 29 c2 89 11 48 83 c8 ff eb eb 90 90 90 90 90 90 90 90 90 b8 0b 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8d 0d 5d ad 20 00 31 d2 48 29 c2 89
RSP: 002b:00007ffd0835d0d8 EFLAGS: 00000203 ORIG_RAX: 000000000000000b
RAX: ffffffffffffffda RBX: 00007f14c83761c8 RCX: 00007f14c816b417
1 lock held by syz-executor2/13706:
RDX: 00000000011b1e00 RSI: 00000000000033ef RDI: 00007f14c836e000
kobject: 'loop1' (00000000690fce5f): fill_kobj_path: path = '/devices/virtual/block/loop1'
RBP: 00007ffd0835d240 R08: 0000000000000001 R09: 0000000000000007
R10: 00007f14c8165a0b R11: 0000000000000203 R12: 00000000017357a4
R13: 000005f3017357a4 R14: 000005f3005926b2 R15: 00007f14c836c700
Kernel Offset: disabled
Rebooting in 86400 seconds..