RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007eff30d38dd9 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000007 RBP: 00007ffe8409d460 R08: 0000000000000002 R09: 00007eff30003431 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000008 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 BUG: unable to handle kernel NULL pointer dereference at 0000000000000120 IP: set_bit arch/x86/include/asm/bitops.h:81 [inline] IP: cpumask_set_cpu include/linux/cpumask.h:283 [inline] IP: blk_mq_map_swqueue+0x253/0x990 block/blk-mq.c:2171 PGD a9c95067 P4D a9c95067 PUD a9f35067 PMD 0 Oops: 0002 [#1] PREEMPT SMP KASAN Modules linked in: CPU: 1 PID: 7968 Comm: syz-executor246 Not tainted 4.14.285-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff88809a1f0340 task.stack: ffff8880915a0000 RIP: 0010:set_bit arch/x86/include/asm/bitops.h:81 [inline] RIP: 0010:cpumask_set_cpu include/linux/cpumask.h:283 [inline] RIP: 0010:blk_mq_map_swqueue+0x253/0x990 block/blk-mq.c:2171 RSP: 0018:ffff8880915a7a80 EFLAGS: 00010297 RAX: ffff88809a1f0340 RBX: ffff8880ae99b0b0 RCX: 1ffff11015d1bfd1 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff88cc7d68 RBP: 0000000000000001 R08: ffff8880ae8dfe80 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: ffff8882386b0280 R14: 0000000000000000 R15: dffffc0000000000 FS: 0000555556b04300(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000120 CR3: 00000000a56b1000 CR4: 00000000003406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: blk_mq_queue_reinit block/blk-mq.c:2514 [inline] __blk_mq_update_nr_hw_queues block/blk-mq.c:2752 [inline] blk_mq_update_nr_hw_queues+0x246/0x3e0 block/blk-mq.c:2762 nbd_start_device+0x1d7/0xca0 drivers/block/nbd.c:1201 nbd_start_device_ioctl drivers/block/nbd.c:1252 [inline] __nbd_ioctl drivers/block/nbd.c:1334 [inline] nbd_ioctl+0x3c4/0xac0 drivers/block/nbd.c:1374 __blkdev_driver_ioctl block/ioctl.c:297 [inline] blkdev_ioctl+0x540/0x1830 block/ioctl.c:594 block_ioctl+0xd9/0x120 fs/block_dev.c:1893 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7eff30d38dd9 RSP: 002b:00007ffe8409d458 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007eff30d38dd9 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000007 RBP: 00007ffe8409d460 R08: 0000000000000002 R09: 00007eff30003431 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000008 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Code: 4d 8d 34 c8 4c 89 f1 48 c1 e9 03 42 80 3c 39 00 0f 85 37 05 00 00 83 fd 07 4d 8b 36 0f 87 42 04 00 00 48 89 04 24 e8 6d 3d 4a fe 4d 0f ab a6 20 01 00 00 49 8d be 78 01 00 00 48 8b 04 24 48 RIP: set_bit arch/x86/include/asm/bitops.h:81 [inline] RSP: ffff8880915a7a80 RIP: cpumask_set_cpu include/linux/cpumask.h:283 [inline] RSP: ffff8880915a7a80 RIP: blk_mq_map_swqueue+0x253/0x990 block/blk-mq.c:2171 RSP: ffff8880915a7a80 CR2: 0000000000000120 ---[ end trace 076375593567f551 ]--- ---------------- Code disassembly (best guess): 0: 4d 8d 34 c8 lea (%r8,%rcx,8),%r14 4: 4c 89 f1 mov %r14,%rcx 7: 48 c1 e9 03 shr $0x3,%rcx b: 42 80 3c 39 00 cmpb $0x0,(%rcx,%r15,1) 10: 0f 85 37 05 00 00 jne 0x54d 16: 83 fd 07 cmp $0x7,%ebp 19: 4d 8b 36 mov (%r14),%r14 1c: 0f 87 42 04 00 00 ja 0x464 22: 48 89 04 24 mov %rax,(%rsp) 26: e8 6d 3d 4a fe callq 0xfe4a3d98 * 2b: f0 4d 0f ab a6 20 01 lock bts %r12,0x120(%r14) <-- trapping instruction 32: 00 00 34: 49 8d be 78 01 00 00 lea 0x178(%r14),%rdi 3b: 48 8b 04 24 mov (%rsp),%rax 3f: 48 rex.W