BUG: unable to handle kernel NULL pointer dereference at 0000000000000118
PGD 80157067 P4D 80157067 PUD 89bc0067 PMD 0 
kobject: 'kvm' (00000000a37b5d97): kobject_uevent_env
Oops: 0002 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 9948 Comm: syz-executor.2 Not tainted 4.19.60 #33
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:set_bit /./arch/x86/include/asm/bitops.h:76 [inline]
RIP: 0010:cpumask_set_cpu /./include/linux/cpumask.h:311 [inline]
RIP: 0010:blk_mq_map_swqueue+0x29e/0xa60 /block/blk-mq.c:2345
kobject: 'kvm' (00000000a37b5d97): fill_kobj_path: path = '/devices/virtual/misc/kvm'
Code: 80 3c 18 00 0f 85 ef 06 00 00 44 89 e6 bf 3f 00 00 00 4d 8b 6d 00 e8 71 4b 57 fe 41 83 fc 3f 0f 87 11 05 00 00 e8 e2 49 57 fe <f0> 4d 0f ab b5 18 01 00 00 49 8d bd 74 01 00 00 48 89 fa 48 c1 ea
RSP: 0018:ffff8880972a78c0 EFLAGS: 00010246
RAX: 0000000000040000 RBX: dffffc0000000000 RCX: ffffc9000a291000
RDX: 0000000000040000 RSI: ffffffff8313cf7e RDI: 0000000000000005
RBP: ffff8880972a7930 R08: ffff888095904440 R09: 0000000000000000
R10: ffffed10099b9ff0 R11: ffff88804cdcff83 R12: 0000000000000001
R13: 0000000000000000 R14: 0000000000000001 R15: ffff8880a417e0c0
FS:  00007f6a78a16700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000118 CR3: 000000008b9b4000 CR4: 00000000001426e0
Call Trace:
 blk_mq_queue_reinit /block/blk-mq.c:2686 [inline]
 __blk_mq_update_nr_hw_queues /block/blk-mq.c:3007 [inline]
 blk_mq_update_nr_hw_queues+0x5ab/0xb70 /block/blk-mq.c:3021
 nbd_start_device+0x15e/0xbb0 /drivers/block/nbd.c:1155
 nbd_start_device_ioctl /drivers/block/nbd.c:1196 [inline]
 __nbd_ioctl /drivers/block/nbd.c:1267 [inline]
 nbd_ioctl+0x40d/0xc60 /drivers/block/nbd.c:1307
 __blkdev_driver_ioctl /block/ioctl.c:303 [inline]
 blkdev_ioctl+0xc38/0x1ac0 /block/ioctl.c:601
 block_ioctl+0xee/0x130 /fs/block_dev.c:1891
 vfs_ioctl /fs/ioctl.c:46 [inline]
 file_ioctl /fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0xd5f/0x1380 /fs/ioctl.c:688
 ksys_ioctl+0xab/0xd0 /fs/ioctl.c:705
 __do_sys_ioctl /fs/ioctl.c:712 [inline]
 __se_sys_ioctl /fs/ioctl.c:710 [inline]
 __x64_sys_ioctl+0x73/0xb0 /fs/ioctl.c:710
 do_syscall_64+0xfd/0x620 /arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459819
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:00007f6a78a15c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f6a78a15c90 RCX: 0000000000459819
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000005
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f6a78a166d4
R13: 00000000004c303d R14: 00000000004d64f0 R15: 0000000000000006
Modules linked in:
CR2: 0000000000000118
---[ end trace 840603339a2355d0 ]---
kobject: 'loop0' (000000005e6aee84): kobject_uevent_env
RIP: 0010:set_bit /./arch/x86/include/asm/bitops.h:76 [inline]
RIP: 0010:cpumask_set_cpu /./include/linux/cpumask.h:311 [inline]
RIP: 0010:blk_mq_map_swqueue+0x29e/0xa60 /block/blk-mq.c:2345
Code: 80 3c 18 00 0f 85 ef 06 00 00 44 89 e6 bf 3f 00 00 00 4d 8b 6d 00 e8 71 4b 57 fe 41 83 fc 3f 0f 87 11 05 00 00 e8 e2 49 57 fe <f0> 4d 0f ab b5 18 01 00 00 49 8d bd 74 01 00 00 48 89 fa 48 c1 ea
kobject: 'batman_adv' (000000003edb377c): kobject_uevent_env
RSP: 0018:ffff8880972a78c0 EFLAGS: 00010246
kobject: 'loop0' (000000005e6aee84): fill_kobj_path: path = '/devices/virtual/block/loop0'
RAX: 0000000000040000 RBX: dffffc0000000000 RCX: ffffc9000a291000
kobject: 'loop4' (000000005225a887): kobject_uevent_env
RDX: 0000000000040000 RSI: ffffffff8313cf7e RDI: 0000000000000005
kobject: 'batman_adv' (000000003edb377c): kobject_uevent_env: filter function caused the event to drop!
RBP: ffff8880972a7930 R08: ffff888095904440 R09: 0000000000000000
kobject: 'loop4' (000000005225a887): fill_kobj_path: path = '/devices/virtual/block/loop4'
R10: ffffed10099b9ff0 R11: ffff88804cdcff83 R12: 0000000000000001
kobject: 'batman_adv' (000000003edb377c): kobject_cleanup, parent           (null)
R13: 0000000000000000 R14: 0000000000000001 R15: ffff8880a417e0c0
FS:  00007f6a78a16700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
kobject: 'batman_adv' (000000003edb377c): calling ktype release
kobject: 'loop3' (000000002e4cebf8): kobject_uevent_env
CR2: 0000000000000118 CR3: 000000008b9b4000 CR4: 00000000001426e0
kobject: (000000003edb377c): dynamic_kobj_release