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BUG: KASAN: use-after-free in __lock_acquire.constprop.0+0xab4/0xb20 kernel/locking/lockdep.c:4774
Read of size 8 at addr ffff88810e1854c0 by task syz.2.16/3540

CPU: 0 PID: 3540 Comm: syz.2.16 Not tainted 5.12.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x8f/0xc7 lib/dump_stack.c:120
 print_address_description.constprop.0+0x18/0x170 mm/kasan/report.c:232
 __kasan_report mm/kasan/report.c:399 [inline]
 kasan_report.cold+0x7f/0x111 mm/kasan/report.c:416
 __lock_acquire.constprop.0+0xab4/0xb20 kernel/locking/lockdep.c:4774
 lock_acquire kernel/locking/lockdep.c:5510 [inline]
 lock_acquire+0x11a/0x230 kernel/locking/lockdep.c:5475
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x26/0x40 kernel/locking/spinlock.c:159
 remove_wait_queue+0x21/0x180 kernel/sched/wait.c:55
 ep_remove_wait_queue fs/eventpoll.c:545 [inline]
 ep_unregister_pollwait.constprop.0+0xbf/0x150 fs/eventpoll.c:561
 ep_free+0x11e/0x280 fs/eventpoll.c:750
 ep_eventpoll_release+0x33/0x50 fs/eventpoll.c:782
 __fput+0x1a9/0x770 fs/file_table.c:280
 task_work_run+0xc5/0x150 kernel/task_work.c:140
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:174 [inline]
 exit_to_user_mode_prepare+0x139/0x140 kernel/entry/common.c:208
 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline]
 syscall_exit_to_user_mode+0x13/0x40 kernel/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f21f0a2e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc09cd6688 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 000000000000f01a RCX: 00007f21f0a2e929
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f21f0c57ba0 R08: 0000000000000001 R09: 0000000409cd697f
R10: 00007f21f08a0000 R11: 0000000000000246 R12: 00007f21f0c55fac
R13: 00007f21f0c55fa0 R14: ffffffffffffffff R15: 00007ffc09cd67a0

Allocated by task 1:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:427 [inline]
 ____kasan_kmalloc mm/kasan/common.c:506 [inline]
 ____kasan_kmalloc mm/kasan/common.c:465 [inline]
 __kasan_kmalloc+0x99/0xc0 mm/kasan/common.c:515
 kmalloc include/linux/slab.h:554 [inline]
 kzalloc include/linux/slab.h:684 [inline]
 __comedi_device_postconfig_async drivers/comedi/drivers.c:664 [inline]
 __comedi_device_postconfig+0x255/0x860 drivers/comedi/drivers.c:721
 comedi_device_postconfig drivers/comedi/drivers.c:756 [inline]
 comedi_auto_config+0x182/0x250 drivers/comedi/drivers.c:1069
 comedi_test_init+0xa8/0xee drivers/comedi/drivers/comedi_test.c:812
 do_one_initcall+0xb9/0x2d0 init/main.c:1226
 do_initcall_level init/main.c:1299 [inline]
 do_initcalls init/main.c:1315 [inline]
 do_basic_setup init/main.c:1335 [inline]
 kernel_init_freeable+0x53d/0x5a0 init/main.c:1537
 kernel_init+0x8/0x115 init/main.c:1424
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Freed by task 3541:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46
 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:357
 ____kasan_slab_free mm/kasan/common.c:360 [inline]
 ____kasan_slab_free mm/kasan/common.c:325 [inline]
 __kasan_slab_free+0xe3/0x120 mm/kasan/common.c:367
 kasan_slab_free include/linux/kasan.h:199 [inline]
 slab_free_hook mm/slub.c:1562 [inline]
 slab_free_freelist_hook+0x6a/0x1b0 mm/slub.c:1600
 slab_free mm/slub.c:3161 [inline]
 kfree+0xd8/0x520 mm/slub.c:4213
 comedi_device_detach_cleanup drivers/comedi/drivers.c:172 [inline]
 comedi_device_detach+0x260/0x8d0 drivers/comedi/drivers.c:208
 do_devconfig_ioctl+0x33f/0x3f0 drivers/comedi/comedi_fops.c:829
 comedi_unlocked_ioctl+0x1319/0x29b0 drivers/comedi/comedi_fops.c:2131
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl fs/ioctl.c:739 [inline]
 __x64_sys_ioctl+0x122/0x190 fs/ioctl.c:739
 do_syscall_64+0x34/0x50 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

The buggy address belongs to the object at ffff88810e185400
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 192 bytes inside of
 256-byte region [ffff88810e185400, ffff88810e185500)
The buggy address belongs to the page:
page:ffffea0004386100 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10e184
head:ffffea0004386100 order:1 compound_mapcount:0
flags: 0x200000000010200(slab|head)
raw: 0200000000010200 dead000000000100 dead000000000122 ffff888100041b40
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 5829918329
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook mm/page_alloc.c:2302 [inline]
 prep_new_page mm/page_alloc.c:2311 [inline]
 get_page_from_freelist+0x3eb6/0x5100 mm/page_alloc.c:3951
 __alloc_pages_nodemask+0x2d1/0x620 mm/page_alloc.c:5001
 __alloc_pages include/linux/gfp.h:525 [inline]
 alloc_page_interleave+0xf/0x140 mm/mempolicy.c:2143
 alloc_pages include/linux/gfp.h:561 [inline]
 alloc_slab_page mm/slub.c:1638 [inline]
 allocate_slab+0x2a5/0x470 mm/slub.c:1778
 new_slab mm/slub.c:1841 [inline]
 new_slab_objects mm/slub.c:2587 [inline]
 ___slab_alloc+0x415/0x6c0 mm/slub.c:2750
 __slab_alloc+0xd/0x30 mm/slub.c:2790
 slab_alloc_node mm/slub.c:2871 [inline]
 slab_alloc mm/slub.c:2915 [inline]
 kmem_cache_alloc_trace+0x2d6/0x310 mm/slub.c:2932
 kmalloc include/linux/slab.h:554 [inline]
 kzalloc include/linux/slab.h:684 [inline]
 bus_add_driver+0xb6/0x570 drivers/base/bus.c:606
 driver_register+0x20a/0x380 drivers/base/driver.c:171
 __hid_register_driver+0x137/0x210 drivers/hid/hid-core.c:2556
 do_one_initcall+0xb9/0x2d0 init/main.c:1226
 do_initcall_level init/main.c:1299 [inline]
 do_initcalls init/main.c:1315 [inline]
 do_basic_setup init/main.c:1335 [inline]
 kernel_init_freeable+0x53d/0x5a0 init/main.c:1537
 kernel_init+0x8/0x115 init/main.c:1424
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88810e185380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88810e185400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88810e185480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff88810e185500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88810e185580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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