syzbot

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BUG: KASAN: use-after-free in __lock_acquire+0xf0/0x651c kernel/locking/lockdep.c:4882
Read of size 8 at addr ffff0000d1bd7ab8 by task syz.0.16/4170

CPU: 1 PID: 4170 Comm: syz.0.16 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call trace:
 dump_backtrace+0x0/0x43c arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf8/0x160 lib/dump_stack.c:106
 print_address_description+0x78/0x30c mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xec/0x15c mm/kasan/report.c:451
 __asan_report_load8_noabort+0x44/0x50 mm/kasan/report_generic.c:309
 __lock_acquire+0xf0/0x651c kernel/locking/lockdep.c:4882
 lock_acquire+0x1f4/0x620 kernel/locking/lockdep.c:5623
 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline]
 _raw_spin_lock_irq+0xcc/0x13c 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+0x168/0x430 io_uring/io_uring.c:5606
 io_poll_task_func+0xe8/0x250 io_uring/io_uring.c:5708
 tctx_task_work+0x284/0x514 io_uring/io_uring.c:2209
 task_work_run+0x12c/0x1e0 kernel/task_work.c:188
 exit_task_work include/linux/task_work.h:33 [inline]
 do_exit+0x684/0x1f58 kernel/exit.c:883
 do_group_exit+0x100/0x268 kernel/exit.c:997
 __do_sys_exit_group kernel/exit.c:1008 [inline]
 __se_sys_exit_group kernel/exit.c:1006 [inline]
 __wake_up_parent+0x0/0x60 kernel/exit.c:1006
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

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+0xb0/0xf0 mm/kasan/common.c:522
 kasan_kmalloc include/linux/kasan.h:264 [inline]
 kmem_cache_alloc_trace+0x274/0x3fc mm/slub.c:3247
 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+0x428/0xb48 drivers/comedi/drivers.c:756
 comedi_auto_config+0x228/0x328 drivers/comedi/drivers.c:1069
 comedi_test_init+0xb0/0x14c drivers/comedi/drivers/comedi_test.c:834
 do_one_initcall+0x228/0x8b0 init/main.c:1302
 do_initcall_level+0x154/0x214 init/main.c:1375
 do_initcalls+0x58/0xac init/main.c:1391
 do_basic_setup+0x8c/0xa0 init/main.c:1410
 kernel_init_freeable+0x404/0x5fc init/main.c:1615
 kernel_init+0x24/0x1d0 init/main.c:1506
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:855

Freed by task 4170:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4c/0x84 mm/kasan/common.c:46
 kasan_set_free_info+0x28/0x4c mm/kasan/generic.c:360
 ____kasan_slab_free+0x118/0x164 mm/kasan/common.c:366
 __kasan_slab_free+0x18/0x28 mm/kasan/common.c:374
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1705 [inline]
 slab_free_freelist_hook+0x128/0x1e8 mm/slub.c:1731
 slab_free mm/slub.c:3499 [inline]
 kfree+0x170/0x40c mm/slub.c:4559
 comedi_device_detach_cleanup drivers/comedi/drivers.c:172 [inline]
 comedi_device_detach+0x2c4/0x5d8 drivers/comedi/drivers.c:208
 do_devconfig_ioctl drivers/comedi/comedi_fops.c:829 [inline]
 comedi_unlocked_ioctl+0xb28/0xdcc drivers/comedi/comedi_fops.c:2131
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl fs/ioctl.c:860 [inline]
 __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

The buggy address belongs to the object at ffff0000d1bd7a00
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 184 bytes inside of
 256-byte region [ffff0000d1bd7a00, ffff0000d1bd7b00)
The buggy address belongs to the page:
page:00000000bf801dee refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x111bd6
head:00000000bf801dee order:1 compound_mapcount:0
flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000010200 dead000000000100 dead000000000122 ffff0000c0002480
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000d1bd7980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff0000d1bd7a00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff0000d1bd7a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                        ^
 ffff0000d1bd7b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff0000d1bd7b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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