RAX: ffffffffffffffda RBX: 00007fa5d4642c90 RCX: 0000000000457579
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000005
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fa5d46436d4
R13: 00000000004c04c1 R14: 00000000004d0660 R15: 0000000000000006
BUG: unable to handle kernel NULL pointer dereference at 0000000000000118
kobject: 'loop5' (000000008170adf5): kobject_uevent_env
PGD 1d871e067 P4D 1d871e067 PUD 1cd122067 PMD 0 
Oops: 0002 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 23964 Comm: syz-executor2 Not tainted 4.19.0-rc6+ #41
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:cpumask_set_cpu include/linux/cpumask.h:311 [inline]
RIP: 0010:blk_mq_map_swqueue+0x29c/0xa70 block/blk-mq.c:2336
Code: 80 3c 1a 00 0f 85 fa 06 00 00 44 89 ee bf 3f 00 00 00 4d 8b 24 24 e8 93 2a 06 fe 41 83 fd 3f 0f 87 1c 05 00 00 e8 74 29 06 fe <f0> 4d 0f ab b4 24 18 01 00 00 49 8d bc 24 74 01 00 00 48 89 fa 48
RSP: 0018:ffff8801896974e0 EFLAGS: 00010246
kobject: 'loop5' (000000008170adf5): fill_kobj_path: path = '/devices/virtual/block/loop5'
RAX: 0000000000040000 RBX: dffffc0000000000 RCX: ffffc90005e92000
RDX: 0000000000040000 RSI: ffffffff83788c0c RDI: 0000000000000005
RBP: ffff880189697550 R08: ffff8801ba044440 R09: 0000000000000000
R10: ffffed00308b1ff0 R11: ffff88018458ff83 R12: 0000000000000000
R13: 0000000000000001 R14: 0000000000000001 R15: ffff8801d1a95000
FS:  00007fa5d4643700(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000118 CR3: 00000001b8dc3000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 blk_mq_queue_reinit block/blk-mq.c:2675 [inline]
 __blk_mq_update_nr_hw_queues block/blk-mq.c:2994 [inline]
 blk_mq_update_nr_hw_queues+0xb2a/0xe50 block/blk-mq.c:3008
 nbd_start_device+0x1d2/0xcd0 drivers/block/nbd.c:1154
 nbd_start_device_ioctl drivers/block/nbd.c:1195 [inline]
 __nbd_ioctl drivers/block/nbd.c:1266 [inline]
 nbd_ioctl+0x6af/0xd40 drivers/block/nbd.c:1306
 __blkdev_driver_ioctl block/ioctl.c:303 [inline]
 blkdev_ioctl+0x9ac/0x2010 block/ioctl.c:601
 block_ioctl+0xee/0x130 fs/block_dev.c:1883
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
 __do_sys_ioctl fs/ioctl.c:709 [inline]
 __se_sys_ioctl fs/ioctl.c:707 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457579
Code: 1d 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 eb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fa5d4642c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fa5d4642c90 RCX: 0000000000457579
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000005
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fa5d46436d4
R13: 00000000004c04c1 R14: 00000000004d0660 R15: 0000000000000006
Modules linked in:
CR2: 0000000000000118
---[ end trace c15e43ae2d3cb5f9 ]---
RIP: 0010:cpumask_set_cpu include/linux/cpumask.h:311 [inline]
RIP: 0010:blk_mq_map_swqueue+0x29c/0xa70 block/blk-mq.c:2336
Code: 80 3c 1a 00 0f 85 fa 06 00 00 44 89 ee bf 3f 00 00 00 4d 8b 24 24 e8 93 2a 06 fe 41 83 fd 3f 0f 87 1c 05 00 00 e8 74 29 06 fe <f0> 4d 0f ab b4 24 18 01 00 00 49 8d bc 24 74 01 00 00 48 89 fa 48
RSP: 0018:ffff8801896974e0 EFLAGS: 00010246
RAX: 0000000000040000 RBX: dffffc0000000000 RCX: ffffc90005e92000
RDX: 0000000000040000 RSI: ffffffff83788c0c RDI: 0000000000000005
RBP: ffff880189697550 R08: ffff8801ba044440 R09: 0000000000000000
R10: ffffed00308b1ff0 R11: ffff88018458ff83 R12: 0000000000000000
R13: 0000000000000001 R14: 0000000000000001 R15: ffff8801d1a95000
FS:  00007fa5d4643700(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000118 CR3: 00000001b8dc3000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400