================================================================== BUG: KASAN: use-after-free in __lock_acquire+0xf0/0x651c kernel/locking/lockdep.c:4882 Read of size 8 at addr ffff0000d186acb8 by task syz.0.16/4970 CPU: 1 PID: 4970 Comm: syz.0.16 Not tainted 5.15.189-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025 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 get_signal+0x73c/0x1340 kernel/signal.c:2900 do_signal arch/arm64/kernel/signal.c:893 [inline] do_notify_resume+0x35c/0x3128 arch/arm64/kernel/signal.c:946 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:133 [inline] exit_to_user_mode arch/arm64/kernel/entry-common.c:138 [inline] el0_svc+0xf0/0x1e0 arch/arm64/kernel/entry-common.c:609 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 4970: 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 ffff0000d186ac00 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 184 bytes inside of 256-byte region [ffff0000d186ac00, ffff0000d186ad00) The buggy address belongs to the page: page:0000000090cbf337 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11186a head:0000000090cbf337 order:1 compound_mapcount:0 flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff) raw: 05ffc00000010200 fffffc0003461a00 0000000800000008 ffff0000c0002480 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000d186ab80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff0000d186ac00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff0000d186ac80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff0000d186ad00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff0000d186ad80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================