==================================================================
BUG: KASAN: slab-use-after-free in list_empty include/linux/list.h:373 [inline]
BUG: KASAN: slab-use-after-free in waitqueue_active include/linux/wait.h:129 [inline]
BUG: KASAN: slab-use-after-free in wq_has_sleeper include/linux/wait.h:163 [inline]
BUG: KASAN: slab-use-after-free in io_cqring_wake io_uring/io_uring.h:260 [inline]
BUG: KASAN: slab-use-after-free in io_cq_unlock_post io_uring/io_uring.c:647 [inline]
BUG: KASAN: slab-use-after-free in __io_req_complete_post+0x7a2/0x10b0 io_uring/io_uring.c:1012
Read of size 8 at addr ffff88804a6942d8 by task kworker/0:7/17667

CPU: 0 PID: 17667 Comm: kworker/0:7 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Workqueue: events ublk_stop_work_fn
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:468
 kasan_report+0x117/0x150 mm/kasan/report.c:581
 list_empty include/linux/list.h:373 [inline]
 waitqueue_active include/linux/wait.h:129 [inline]
 wq_has_sleeper include/linux/wait.h:163 [inline]
 io_cqring_wake io_uring/io_uring.h:260 [inline]
 io_cq_unlock_post io_uring/io_uring.c:647 [inline]
 __io_req_complete_post+0x7a2/0x10b0 io_uring/io_uring.c:1012
 io_uring_cmd_done+0x266/0x390 io_uring/uring_cmd.c:72
 ublk_cancel_queue drivers/block/ublk_drv.c:1564 [inline]
 ublk_cancel_dev+0x1f7/0x3a0 drivers/block/ublk_drv.c:1577
 ublk_stop_dev+0x367/0x410 drivers/block/ublk_drv.c:1678
 process_one_work kernel/workqueue.c:2653 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2730
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2811
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>

Allocated by task 20946:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 ____kasan_kmalloc mm/kasan/common.c:375 [inline]
 __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:384
 kmalloc include/linux/slab.h:600 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 io_ring_ctx_alloc+0x54/0xc10 io_uring/io_uring.c:289
 io_uring_create+0x2df/0x1330 io_uring/io_uring.c:3993
 io_uring_setup io_uring/io_uring.c:4178 [inline]
 __do_sys_io_uring_setup io_uring/io_uring.c:4205 [inline]
 __se_sys_io_uring_setup+0x29f/0x2b0 io_uring/io_uring.c:4199
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Freed by task 19012:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x28/0x40 mm/kasan/generic.c:522
 ____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237
 kasan_slab_free include/linux/kasan.h:164 [inline]
 slab_free_hook mm/slub.c:1811 [inline]
 slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837
 slab_free mm/slub.c:3830 [inline]
 __kmem_cache_free+0xba/0x1f0 mm/slub.c:3843
 io_ring_exit_work+0x7a6/0x830 io_uring/io_uring.c:3264
 process_one_work kernel/workqueue.c:2653 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2730
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2811
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293

Last potentially related work creation:
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:46
 __kasan_record_aux_stack+0xaf/0xc0 mm/kasan/generic.c:492
 insert_work+0x3d/0x310 kernel/workqueue.c:1670
 __queue_work+0xbfd/0xfd0 kernel/workqueue.c:1819
 queue_work_on+0x128/0x1f0 kernel/workqueue.c:1854
 queue_work include/linux/workqueue.h:562 [inline]
 io_ring_ctx_wait_and_kill+0x256/0x2b0 io_uring/io_uring.c:3296
 io_uring_release+0x42/0x50 io_uring/io_uring.c:3304
 __fput+0x221/0x940 fs/file_table.c:418
 task_work_run+0x1d4/0x260 kernel/task_work.c:245
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0x986/0x2530 kernel/exit.c:884
 do_group_exit+0x22d/0x2f0 kernel/exit.c:1026
 get_signal+0x12a6/0x1390 kernel/signal.c:2903
 arch_do_signal_or_restart+0xc2/0x7b0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

The buggy address belongs to the object at ffff88804a694000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 728 bytes inside of
 freed 4096-byte region [ffff88804a694000, ffff88804a695000)

The buggy address belongs to the physical page:
page:ffffea000129a400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x4a690
head:ffffea000129a400 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888017c42140 0000000000000000 0000000000000001
raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 49, tgid 49 (kworker/u4:3), ts 1951801974752, free_ts 1870263131162
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1c1/0x200 mm/page_alloc.c:1582
 prep_new_page mm/page_alloc.c:1589 [inline]
 get_page_from_freelist+0x2181/0x22a0 mm/page_alloc.c:3221
 __alloc_pages+0x1f0/0x460 mm/page_alloc.c:4501
 alloc_slab_page+0x5d/0x180 mm/slub.c:1881
 allocate_slab mm/slub.c:2028 [inline]
 new_slab+0x87/0x2d0 mm/slub.c:2081
 ___slab_alloc+0xc5c/0x12f0 mm/slub.c:3253
 __slab_alloc mm/slub.c:3339 [inline]
 __slab_alloc_node mm/slub.c:3392 [inline]
 slab_alloc_node mm/slub.c:3485 [inline]
 __kmem_cache_alloc_node+0x11f/0x250 mm/slub.c:3534
 __do_kmalloc_node mm/slab_common.c:1006 [inline]
 __kmalloc_node_track_caller+0xa4/0x230 mm/slab_common.c:1027
 kmalloc_reserve+0x116/0x240 net/core/skbuff.c:584
 __alloc_skb+0x138/0x2c0 net/core/skbuff.c:653
 alloc_skb include/linux/skbuff.h:1316 [inline]
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:748 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:805 [inline]
 nsim_dev_trap_report_work+0x253/0xa90 drivers/net/netdevsim/dev.c:851
 process_one_work kernel/workqueue.c:2653 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2730
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2811
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1182 [inline]
 free_unref_page_prepare+0x7d7/0x8f0 mm/page_alloc.c:2366
 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2459
 discard_slab mm/slub.c:2127 [inline]
 __unfreeze_partials+0x1cf/0x210 mm/slub.c:2667
 put_cpu_partial+0x17c/0x250 mm/slub.c:2743
 __slab_free+0x319/0x400 mm/slub.c:3700
 qlink_free mm/kasan/quarantine.c:166 [inline]
 qlist_free_all+0x75/0xd0 mm/kasan/quarantine.c:185
 kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:306
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook+0x6a/0x4d0 mm/slab.h:770
 slab_alloc_node mm/slub.c:3495 [inline]
 slab_alloc mm/slub.c:3503 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3510 [inline]
 kmem_cache_alloc+0x17e/0x2c0 mm/slub.c:3519
 getname_flags+0xbb/0x500 fs/namei.c:140
 getname fs/namei.c:219 [inline]
 __do_sys_symlinkat fs/namei.c:4527 [inline]
 __se_sys_symlinkat fs/namei.c:4524 [inline]
 __x64_sys_symlinkat+0x7c/0xb0 fs/namei.c:4524
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffff88804a694180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88804a694200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88804a694280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                    ^
 ffff88804a694300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88804a694380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================