BUG: unable to handle kernel NULL pointer dereference at 0000000000000118
PGD a328c067 P4D a328c067 PUD 9daee067 PMD 0 
Oops: 0002 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 31734 Comm: syz-executor.5 Not tainted 4.19.169-syzkaller #0
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+0x297/0xa30 block/blk-mq.c:2360
Code: c1 ea 03 80 3c 1a 00 0f 85 d7 06 00 00 89 ee bf 07 00 00 00 4d 8b 36 e8 b7 6a fe fd 83 fd 07 0f 87 0d 05 00 00 e8 39 69 fe fd <f0> 4d 0f ab ae 18 01 00 00 49 8d be 74 01 00 00 48 89 fa 48 c1 ea
RSP: 0018:ffff888034fc7918 EFLAGS: 00010246
RAX: 0000000000040000 RBX: dffffc0000000000 RCX: ffffc90010913000
RDX: 0000000000040000 RSI: ffffffff8363f117 RDI: 0000000000000005
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000007
R10: 0000000000000005 R11: 0000000000000000 R12: ffffe8ffffd3a640
R13: 0000000000000001 R14: 0000000000000000 R15: ffff8880aebe7040
FS:  00007fb8483cb700(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000118 CR3: 00000000aa2a4000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 blk_mq_queue_reinit block/blk-mq.c:2702 [inline]
 __blk_mq_update_nr_hw_queues block/blk-mq.c:3023 [inline]
 blk_mq_update_nr_hw_queues+0x5bb/0xb50 block/blk-mq.c:3037
 nbd_start_device+0x1f2/0xd60 drivers/block/nbd.c:1206
 nbd_start_device_ioctl drivers/block/nbd.c:1257 [inline]
 __nbd_ioctl drivers/block/nbd.c:1339 [inline]
 nbd_ioctl+0x62c/0xbe0 drivers/block/nbd.c:1379
 __blkdev_driver_ioctl block/ioctl.c:303 [inline]
 blkdev_ioctl+0x5cb/0x1a80 block/ioctl.c:601
 block_ioctl+0xe9/0x130 fs/block_dev.c:1906
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688
 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
 __do_sys_ioctl fs/ioctl.c:712 [inline]
 __se_sys_ioctl fs/ioctl.c:710 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45e219
Code: 0d b4 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 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fb8483cac68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000000000a RCX: 000000000045e219
RDX: ffffffffffffffff RSI: 000000000000ab03 RDI: 0000000000000005
RBP: 00007fb8483caca0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000009
R13: 00007fff663b80bf R14: 00007fb8483cb9c0 R15: 000000000119bf8c
Modules linked in:
CR2: 0000000000000118
---[ end trace bc6c6221b76c1a16 ]---
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+0x297/0xa30 block/blk-mq.c:2360
Code: c1 ea 03 80 3c 1a 00 0f 85 d7 06 00 00 89 ee bf 07 00 00 00 4d 8b 36 e8 b7 6a fe fd 83 fd 07 0f 87 0d 05 00 00 e8 39 69 fe fd <f0> 4d 0f ab ae 18 01 00 00 49 8d be 74 01 00 00 48 89 fa 48 c1 ea
RSP: 0018:ffff888034fc7918 EFLAGS: 00010246
RAX: 0000000000040000 RBX: dffffc0000000000 RCX: ffffc90010913000
RDX: 0000000000040000 RSI: ffffffff8363f117 RDI: 0000000000000005
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000007
R10: 0000000000000005 R11: 0000000000000000 R12: ffffe8ffffd3a640
R13: 0000000000000001 R14: 0000000000000000 R15: ffff8880aebe7040
FS:  00007fb8483cb700(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056165ae87160 CR3: 00000000aa2a4000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400