syzbot

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BUG: KASAN: use-after-free in __lock_acquire+0xf7/0x7c60 kernel/locking/lockdep.c:4882
Read of size 8 at addr ffff88802a2766b8 by task kworker/0:2/1324

CPU: 0 PID: 1324 Comm: kworker/0:2 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: events io_fallback_req_func
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 __lock_acquire+0xf7/0x7c60 kernel/locking/lockdep.c:4882
 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline]
 _raw_spin_lock_irq+0x9f/0xe0 kernel/locking/spinlock.c:170
 spin_lock_irq include/linux/spinlock.h:388 [inline]
 io_poll_remove_entry io_uring/io_uring.c:5578 [inline]
 io_poll_remove_entries+0x187/0x4a0 io_uring/io_uring.c:5606
 io_poll_task_func+0xfe/0x280 io_uring/io_uring.c:5708
 io_fallback_req_func+0xfa/0x200 io_uring/io_uring.c:1280
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Allocated by task 1:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc mm/kasan/common.c:513 [inline]
 __kasan_kmalloc+0xb5/0xf0 mm/kasan/common.c:522
 kmalloc include/linux/slab.h:604 [inline]
 kzalloc include/linux/slab.h:735 [inline]
 __comedi_device_postconfig_async drivers/comedi/drivers.c:664 [inline]
 __comedi_device_postconfig drivers/comedi/drivers.c:721 [inline]
 comedi_device_postconfig+0x496/0xc50 drivers/comedi/drivers.c:756
 comedi_auto_config+0x265/0x3a0 drivers/comedi/drivers.c:1069
 comedi_test_init+0x8f/0x130 drivers/comedi/drivers/comedi_test.c:834
 do_one_initcall+0x1ee/0x680 init/main.c:1302
 do_initcall_level+0x137/0x1f0 init/main.c:1375
 do_initcalls+0x4b/0x90 init/main.c:1391
 kernel_init_freeable+0x3ce/0x560 init/main.c:1615
 kernel_init+0x19/0x1b0 init/main.c:1506
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Freed by task 5357:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1705 [inline]
 slab_free_freelist_hook+0xea/0x170 mm/slub.c:1731
 slab_free mm/slub.c:3499 [inline]
 kfree+0xef/0x2a0 mm/slub.c:4559
 comedi_device_detach_cleanup drivers/comedi/drivers.c:172 [inline]
 comedi_device_detach+0x35f/0x6e0 drivers/comedi/drivers.c:208
 do_devconfig_ioctl drivers/comedi/comedi_fops.c:829 [inline]
 comedi_unlocked_ioctl+0xbd0/0xe90 drivers/comedi/comedi_fops.c:2131
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

The buggy address belongs to the object at ffff88802a276600
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 184 bytes inside of
 256-byte region [ffff88802a276600, ffff88802a276700)
The buggy address belongs to the page:
page:ffffea0000a89d80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2a276
head:ffffea0000a89d80 order:1 compound_mapcount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000122 ffff888016841b40
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, ts 13198751248, free_ts 0
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x1b77/0x1c60 mm/page_alloc.c:4192
 __alloc_pages+0x1e1/0x470 mm/page_alloc.c:5474
 alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2031
 alloc_slab_page mm/slub.c:1775 [inline]
 allocate_slab mm/slub.c:1912 [inline]
 new_slab+0xc0/0x4b0 mm/slub.c:1975
 ___slab_alloc+0x81e/0xdf0 mm/slub.c:3008
 __slab_alloc mm/slub.c:3095 [inline]
 slab_alloc_node mm/slub.c:3186 [inline]
 slab_alloc mm/slub.c:3228 [inline]
 kmem_cache_alloc_trace+0x1a5/0x2a0 mm/slub.c:3245
 kmalloc include/linux/slab.h:604 [inline]
 kzalloc include/linux/slab.h:735 [inline]
 bus_add_driver+0xda/0x5a0 drivers/base/bus.c:604
 driver_register+0x32d/0x430 drivers/base/driver.c:240
 vhost_vdpa_init+0x47/0x80 drivers/vhost/vdpa.c:1228
 do_one_initcall+0x1ee/0x680 init/main.c:1302
 do_initcall_level+0x137/0x1f0 init/main.c:1375
 do_initcalls+0x4b/0x90 init/main.c:1391
 kernel_init_freeable+0x3ce/0x560 init/main.c:1615
 kernel_init+0x19/0x1b0 init/main.c:1506
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88802a276580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88802a276600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88802a276680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                        ^
 ffff88802a276700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88802a276780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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