==================================================================
BUG: KASAN: slab-out-of-bounds in blk_mq_free_rqs+0xde/0x680 block/blk-mq.c:-1
Read of size 8 at addr ffff8880566681c8 by task syz.4.4063/21993

CPU: 0 UID: 0 PID: 21993 Comm: syz.4.4063 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 blk_mq_free_rqs+0xde/0x680 block/blk-mq.c:-1
 blk_mq_free_map_and_rqs+0x40/0xf0 block/blk-mq.c:4148
 blk_mq_free_sched_tags block/blk-mq-sched.c:425 [inline]
 blk_mq_free_sched_res+0xeb/0x280 block/blk-mq-sched.c:436
 elevator_change_done+0x1d2/0x5c0 block/elevator.c:639
 elevator_change+0x34f/0x480 block/elevator.c:685
 elevator_set_none+0xb5/0x140 block/elevator.c:769
 blk_mq_elv_switch_none block/blk-mq.c:5101 [inline]
 __blk_mq_update_nr_hw_queues block/blk-mq.c:5146 [inline]
 blk_mq_update_nr_hw_queues+0x5ef/0x19f0 block/blk-mq.c:5211
 nbd_start_device+0x189/0xb30 drivers/block/nbd.c:1526
 nbd_genl_connect+0x1597/0x1c10 drivers/block/nbd.c:2276
 genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114
 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
 genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209
 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800
 __sock_sendmsg net/socket.c:815 [inline]
 ____sys_sendmsg+0x54e/0x850 net/socket.c:2713
 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2767
 __sys_sendmsg net/socket.c:2799 [inline]
 __do_sys_sendmsg net/socket.c:2804 [inline]
 __se_sys_sendmsg net/socket.c:2802 [inline]
 __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2802
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff0f6b9e0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff0f7acd028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ff0f6e26090 RCX: 00007ff0f6b9e0d9
RDX: 0000000000000004 RSI: 0000200000001ac0 RDI: 0000000000000006
RBP: 00007ff0f6c35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff0f6e26128 R14: 00007ff0f6e26090 R15: 00007fffbb5228e8
 </TASK>

Allocated by task 16786:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5334 [inline]
 __kmalloc_node_noprof+0x4cc/0x740 mm/slub.c:5346
 _kmalloc_array_node_noprof include/linux/slab.h:1294 [inline]
 blk_mq_alloc_tag_set+0x533/0x1000 block/blk-mq.c:4894
 nbd_dev_add+0x30e/0xb60 drivers/block/nbd.c:1970
 nbd_genl_connect+0x992/0x1c10 drivers/block/nbd.c:2162
 genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114
 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
 genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209
 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800
 __sock_sendmsg net/socket.c:815 [inline]
 ____sys_sendmsg+0x54e/0x850 net/socket.c:2713
 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2767
 __sys_sendmsg net/socket.c:2799 [inline]
 __do_sys_sendmsg net/socket.c:2804 [inline]
 __se_sys_sendmsg net/socket.c:2802 [inline]
 __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2802
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff8880566681c0
 which belongs to the cache kmalloc-8 of size 8
The buggy address is located 0 bytes to the right of
 allocated 8-byte region [ffff8880566681c0, ffff8880566681c8)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x56668
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88801b002500 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800800080 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5628, tgid 5628 (syz-executor), ts 333740482700, free_ts 333740457629
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0x21fe/0x2270 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5304
 alloc_slab_page mm/slub.c:3266 [inline]
 allocate_slab+0x79/0x5e0 mm/slub.c:3380
 new_slab mm/slub.c:3426 [inline]
 refill_objects+0x2d5/0x350 mm/slub.c:7310
 refill_sheaf mm/slub.c:2804 [inline]
 __pcs_replace_empty_main+0x2c3/0x6b0 mm/slub.c:4675
 alloc_from_pcs mm/slub.c:4773 [inline]
 slab_alloc_node mm/slub.c:4905 [inline]
 __do_kmalloc_node mm/slub.c:5333 [inline]
 __kmalloc_node_noprof+0x560/0x740 mm/slub.c:5346
 _kmalloc_node_noprof include/linux/slab.h:1197 [inline]
 __vmalloc_area_node mm/vmalloc.c:3893 [inline]
 __vmalloc_node_range_noprof+0x5d9/0x1730 mm/vmalloc.c:4104
 __vmalloc_node_noprof mm/vmalloc.c:4165 [inline]
 vzalloc_noprof+0xb2/0xe0 mm/vmalloc.c:4243
 alloc_counters+0x63/0x5c0 net/ipv4/netfilter/ip_tables.c:799
 copy_entries_to_user net/ipv4/netfilter/ip_tables.c:821 [inline]
 get_entries net/ipv4/netfilter/ip_tables.c:1020 [inline]
 do_ipt_get_ctl+0xb3c/0x1300 net/ipv4/netfilter/ip_tables.c:1669
 nf_getsockopt+0x26e/0x290 net/netfilter/nf_sockopt.c:116
 ip_getsockopt+0x19e/0x230 net/ipv4/ip_sockglue.c:1777
 do_sock_getsockopt+0x51d/0x7e0 net/socket.c:2503
 __sys_getsockopt net/socket.c:2534 [inline]
 __do_sys_getsockopt net/socket.c:2541 [inline]
 __se_sys_getsockopt net/socket.c:2538 [inline]
 __x64_sys_getsockopt+0x1a4/0x240 net/socket.c:2538
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
page last free pid 5628 tgid 5628 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0xc22/0xd20 mm/page_alloc.c:2950
 __kasan_populate_vmalloc_do mm/kasan/shadow.c:393 [inline]
 __kasan_populate_vmalloc+0x1a8/0x1c0 mm/kasan/shadow.c:424
 kasan_populate_vmalloc include/linux/kasan.h:580 [inline]
 alloc_vmap_area+0xd1a/0x1420 mm/vmalloc.c:2145
 __get_vm_area_node+0x200/0x2f0 mm/vmalloc.c:3248
 __vmalloc_node_range_noprof+0x358/0x1730 mm/vmalloc.c:4064
 __vmalloc_node_noprof mm/vmalloc.c:4165 [inline]
 vzalloc_noprof+0xb2/0xe0 mm/vmalloc.c:4243
 alloc_counters+0x63/0x5c0 net/ipv4/netfilter/ip_tables.c:799
 copy_entries_to_user net/ipv4/netfilter/ip_tables.c:821 [inline]
 get_entries net/ipv4/netfilter/ip_tables.c:1020 [inline]
 do_ipt_get_ctl+0xb3c/0x1300 net/ipv4/netfilter/ip_tables.c:1669
 nf_getsockopt+0x26e/0x290 net/netfilter/nf_sockopt.c:116
 ip_getsockopt+0x19e/0x230 net/ipv4/ip_sockglue.c:1777
 do_sock_getsockopt+0x51d/0x7e0 net/socket.c:2503
 __sys_getsockopt net/socket.c:2534 [inline]
 __do_sys_getsockopt net/socket.c:2541 [inline]
 __se_sys_getsockopt net/socket.c:2538 [inline]
 __x64_sys_getsockopt+0x1a4/0x240 net/socket.c:2538
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888056668080: 05 fc fc fc 06 fc fc fc 04 fc fc fc 05 fc fc fc
 ffff888056668100: 05 fc fc fc 05 fc fc fc 04 fc fc fc 04 fc fc fc
>ffff888056668180: 06 fc fc fc 04 fc fc fc 00 fc fc fc 05 fc fc fc
                                              ^
 ffff888056668200: 05 fc fc fc 03 fc fc fc 05 fc fc fc 04 fc fc fc
 ffff888056668280: 05 fc fc fc 05 fc fc fc 05 fc fc fc 03 fc fc fc
==================================================================