BUG: KASAN: slab-use-after-free in pwq_release_workfn+0x339/0x380 kernel/workqueue.c:4124
Read of size 4 at addr ffff88802b0b05c0 by task pool_workqueue_/3

CPU: 1 PID: 3 Comm: pool_workqueue_ Not tainted 6.6.0-rc4-syzkaller-00037-g3006adf3be79 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xc4/0x620 mm/kasan/report.c:475
 kasan_report+0xda/0x110 mm/kasan/report.c:588
 pwq_release_workfn+0x339/0x380 kernel/workqueue.c:4124
 kthread_worker_fn+0x2ff/0xac0 kernel/kthread.c:823
 kthread+0x33c/0x440 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
 </TASK>

Allocated by task 14053:
 kasan_save_stack+0x33/0x50 mm/kasan/common.c:45
 kasan_set_track+0x25/0x30 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:374 [inline]
 __kasan_kmalloc+0xa2/0xb0 mm/kasan/common.c:383
 kmalloc include/linux/slab.h:599 [inline]
 kzalloc include/linux/slab.h:720 [inline]
 alloc_workqueue+0x16f/0x1490 kernel/workqueue.c:4684
 nbd_dev_add+0x452/0xcb0 drivers/block/nbd.c:1794
 nbd_genl_connect+0x74f/0x1ca0 drivers/block/nbd.c:1969
 genl_family_rcv_msg_doit+0x1fc/0x2e0 net/netlink/genetlink.c:971
 genl_family_rcv_msg net/netlink/genetlink.c:1051 [inline]
 genl_rcv_msg+0x55c/0x800 net/netlink/genetlink.c:1066
 netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2545
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1075
 netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline]
 netlink_unicast+0x536/0x810 net/netlink/af_netlink.c:1368
 netlink_sendmsg+0x93c/0xe40 net/netlink/af_netlink.c:1910
 sock_sendmsg_nosec net/socket.c:730 [inline]
 sock_sendmsg+0xd9/0x180 net/socket.c:753
 ____sys_sendmsg+0x6ac/0x940 net/socket.c:2541
 ___sys_sendmsg+0x135/0x1d0 net/socket.c:2595
 __sys_sendmsg+0x117/0x1e0 net/socket.c:2624
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0x61/0xe0 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
 entry_SYSENTER_compat_after_hwframe+0x70/0x82

Freed by task 14053:
 kasan_save_stack+0x33/0x50 mm/kasan/common.c:45
 kasan_set_track+0x25/0x30 mm/kasan/common.c:52
 kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:522
 ____kasan_slab_free mm/kasan/common.c:236 [inline]
 ____kasan_slab_free+0x15b/0x1b0 mm/kasan/common.c:200
 kasan_slab_free include/linux/kasan.h:164 [inline]
 slab_free_hook mm/slub.c:1800 [inline]
 slab_free_freelist_hook+0x114/0x1e0 mm/slub.c:1826
 slab_free mm/slub.c:3809 [inline]
 __kmem_cache_free+0xb8/0x2f0 mm/slub.c:3822
 alloc_workqueue+0xe76/0x1490 kernel/workqueue.c:4746
 nbd_dev_add+0x452/0xcb0 drivers/block/nbd.c:1794
 nbd_genl_connect+0x74f/0x1ca0 drivers/block/nbd.c:1969
 genl_family_rcv_msg_doit+0x1fc/0x2e0 net/netlink/genetlink.c:971
 genl_family_rcv_msg net/netlink/genetlink.c:1051 [inline]
 genl_rcv_msg+0x55c/0x800 net/netlink/genetlink.c:1066
 netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2545
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1075
 netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline]
 netlink_unicast+0x536/0x810 net/netlink/af_netlink.c:1368
 netlink_sendmsg+0x93c/0xe40 net/netlink/af_netlink.c:1910
 sock_sendmsg_nosec net/socket.c:730 [inline]
 sock_sendmsg+0xd9/0x180 net/socket.c:753
 ____sys_sendmsg+0x6ac/0x940 net/socket.c:2541
 ___sys_sendmsg+0x135/0x1d0 net/socket.c:2595
 __sys_sendmsg+0x117/0x1e0 net/socket.c:2624
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0x61/0xe0 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
 entry_SYSENTER_compat_after_hwframe+0x70/0x82

Last potentially related work creation:
 kasan_save_stack+0x33/0x50 mm/kasan/common.c:45
 __kasan_record_aux_stack+0xbc/0xd0 mm/kasan/generic.c:492
 __call_rcu_common.constprop.0+0x9a/0x790 kernel/rcu/tree.c:2653
 pwq_release_workfn+0x244/0x380 kernel/workqueue.c:4138
 kthread_worker_fn+0x2ff/0xac0 kernel/kthread.c:823
 kthread+0x33c/0x440 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304

Second to last potentially related work creation:
 kasan_save_stack+0x33/0x50 mm/kasan/common.c:45
 __kasan_record_aux_stack+0xbc/0xd0 mm/kasan/generic.c:492
 __call_rcu_common.constprop.0+0x9a/0x790 kernel/rcu/tree.c:2653
 pwq_release_workfn+0x244/0x380 kernel/workqueue.c:4138
 kthread_worker_fn+0x2ff/0xac0 kernel/kthread.c:823
 kthread+0x33c/0x440 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304

The buggy address belongs to the object at ffff88802b0b0400
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 448 bytes inside of
 freed 512-byte region [ffff88802b0b0400, ffff88802b0b0600)

The buggy address belongs to the physical page:
page:ffffea0000ac2c00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2b0b0
head:ffffea0000ac2c00 order:2 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888012c42c80 ffffea0000852c00 dead000000000002
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x1d2000(__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 7015, tgid 7014 (syz-executor.2), ts 3485230226645, free_ts 3484604870800
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x2cf/0x340 mm/page_alloc.c:1536
 prep_new_page mm/page_alloc.c:1543 [inline]
 get_page_from_freelist+0xee0/0x2f20 mm/page_alloc.c:3170
 __alloc_pages+0x1d0/0x4a0 mm/page_alloc.c:4426
 __alloc_pages_node include/linux/gfp.h:237 [inline]
 alloc_slab_page mm/slub.c:1872 [inline]
 allocate_slab+0xa1/0x380 mm/slub.c:2017
 new_slab mm/slub.c:2070 [inline]
 ___slab_alloc+0x8c7/0x1580 mm/slub.c:3223
 __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3322
 __slab_alloc_node mm/slub.c:3375 [inline]
 slab_alloc_node mm/slub.c:3468 [inline]
 __kmem_cache_alloc_node+0x131/0x340 mm/slub.c:3517
 __do_kmalloc_node mm/slab_common.c:1022 [inline]
 __kmalloc_node+0x52/0x110 mm/slab_common.c:1030
 kmalloc_node include/linux/slab.h:619 [inline]
 kzalloc_node include/linux/slab.h:731 [inline]
 blk_alloc_flush_queue+0x111/0x2b0 block/blk-flush.c:498
 blk_mq_alloc_hctx block/blk-mq.c:3730 [inline]
 blk_mq_alloc_and_init_hctx+0xc1e/0x1190 block/blk-mq.c:4169
 blk_mq_realloc_hw_ctxs+0x4ba/0x630 block/blk-mq.c:4202
 blk_mq_init_allocated_queue+0x39d/0x1360 block/blk-mq.c:4255
 blk_mq_init_queue_data block/blk-mq.c:4074 [inline]
 __blk_mq_alloc_disk+0x95/0x1a0 block/blk-mq.c:4121
 nbd_dev_add+0x3ca/0xcb0 drivers/block/nbd.c:1787
 nbd_genl_connect+0x74f/0x1ca0 drivers/block/nbd.c:1969
 genl_family_rcv_msg_doit+0x1fc/0x2e0 net/netlink/genetlink.c:971
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1136 [inline]
 free_unref_page_prepare+0x476/0xa40 mm/page_alloc.c:2312
 free_unref_page+0x33/0x3b0 mm/page_alloc.c:2405
 __unfreeze_partials+0x21d/0x240 mm/slub.c:2655
 qlink_free mm/kasan/quarantine.c:166 [inline]
 qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:185
 kasan_quarantine_reduce+0x18e/0x1d0 mm/kasan/quarantine.c:292
 __kasan_slab_alloc+0x65/0x90 mm/kasan/common.c:305
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook mm/slab.h:762 [inline]
 slab_alloc_node mm/slub.c:3478 [inline]
 slab_alloc mm/slub.c:3486 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3493 [inline]
 kmem_cache_alloc+0x16c/0x3b0 mm/slub.c:3502
 getname_flags.part.0+0x50/0x4d0 fs/namei.c:140
 getname_flags+0x9c/0xf0 include/linux/audit.h:321
 user_path_at_empty+0x2c/0x60 fs/namei.c:2909
 user_path_at include/linux/namei.h:57 [inline]
 user_statfs+0xa3/0x180 fs/statfs.c:103
 __do_sys_statfs+0x8a/0x100 fs/statfs.c:195
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
 ffff88802b0b0480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88802b0b0500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88802b0b0580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff88802b0b0600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88802b0b0680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================