================================================================== BUG: KASAN: use-after-free in __lock_acquire+0xf7/0x7c50 kernel/locking/lockdep.c:4919 Read of size 8 at addr ffff88802e8c46b8 by task syz.1.713/7613 CPU: 1 PID: 7613 Comm: syz.1.713 Not tainted 6.1.148-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106 print_address_description mm/kasan/report.c:316 [inline] print_report+0xa8/0x210 mm/kasan/report.c:420 kasan_report+0x10b/0x140 mm/kasan/report.c:524 __lock_acquire+0xf7/0x7c50 kernel/locking/lockdep.c:4919 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162 remove_wait_queue+0x20/0x120 kernel/sched/wait.c:54 free_poll_entry fs/select.c:132 [inline] poll_freewait+0x99/0x210 fs/select.c:141 do_sys_poll+0xe8a/0x11f0 fs/select.c:1013 __do_sys_ppoll fs/select.c:1118 [inline] __se_sys_ppoll+0x1fc/0x260 fs/select.c:1098 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f852998ebe9 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:00007f8527bf6038 EFLAGS: 00000246 ORIG_RAX: 000000000000010f RAX: ffffffffffffffda RBX: 00007f8529bb5fa0 RCX: 00007f852998ebe9 RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000200000000100 RBP: 00007f8529a11e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8529bb6038 R14: 00007f8529bb5fa0 R15: 00007ffdfeff2d08 Allocated by task 1: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:52 ____kasan_kmalloc mm/kasan/common.c:374 [inline] __kasan_kmalloc+0x8e/0xa0 mm/kasan/common.c:383 kmalloc include/linux/slab.h:563 [inline] kzalloc include/linux/slab.h:699 [inline] __comedi_device_postconfig_async drivers/comedi/drivers.c:666 [inline] __comedi_device_postconfig drivers/comedi/drivers.c:723 [inline] comedi_device_postconfig+0x496/0xc50 drivers/comedi/drivers.c:758 comedi_auto_config+0x265/0x3a0 drivers/comedi/drivers.c:1071 comedi_test_init+0x8f/0x127 drivers/comedi/drivers/comedi_test.c:832 do_one_initcall+0x214/0x7a0 init/main.c:1298 do_initcall_level+0x137/0x1e4 init/main.c:1371 do_initcalls+0x4b/0x8a init/main.c:1387 kernel_init_freeable+0x3fa/0x5ac init/main.c:1626 kernel_init+0x19/0x1b0 init/main.c:1514 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Freed by task 7615: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:52 kasan_save_free_info+0x2d/0x50 mm/kasan/generic.c:516 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1724 [inline] slab_free_freelist_hook+0x131/0x1a0 mm/slub.c:1750 slab_free mm/slub.c:3661 [inline] __kmem_cache_free+0xb6/0x1f0 mm/slub.c:3674 comedi_device_detach_cleanup drivers/comedi/drivers.c:171 [inline] comedi_device_detach+0x35f/0x6e0 drivers/comedi/drivers.c:207 do_devconfig_ioctl drivers/comedi/comedi_fops.c:829 [inline] comedi_unlocked_ioctl+0xb6b/0xf20 drivers/comedi/comedi_fops.c:2151 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 The buggy address belongs to the object at ffff88802e8c4600 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 184 bytes inside of 256-byte region [ffff88802e8c4600, ffff88802e8c4700) The buggy address belongs to the physical page: page:ffffea0000ba3100 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2e8c4 head:ffffea0000ba3100 order:1 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 dead000000000122 ffff888017441b40 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, tgid 1 (swapper/0), ts 20880604675, free_ts 0 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2532 prep_new_page mm/page_alloc.c:2539 [inline] get_page_from_freelist+0x1a26/0x1ac0 mm/page_alloc.c:4328 __alloc_pages+0x1df/0x4e0 mm/page_alloc.c:5614 alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2115 alloc_slab_page+0x5d/0x160 mm/slub.c:1794 allocate_slab mm/slub.c:1939 [inline] new_slab+0x87/0x2c0 mm/slub.c:1992 ___slab_alloc+0xbc6/0x1220 mm/slub.c:3180 __slab_alloc mm/slub.c:3279 [inline] slab_alloc_node mm/slub.c:3364 [inline] __kmem_cache_alloc_node+0x1a0/0x260 mm/slub.c:3437 kmalloc_trace+0x26/0xe0 mm/slab_common.c:1026 kmalloc include/linux/slab.h:563 [inline] kzalloc include/linux/slab.h:699 [inline] bus_add_driver+0xda/0x5a0 drivers/base/bus.c:604 driver_register+0x32d/0x430 drivers/base/driver.c:246 vhost_vdpa_init+0x47/0x79 drivers/vhost/vdpa.c:1473 do_one_initcall+0x214/0x7a0 init/main.c:1298 do_initcall_level+0x137/0x1e4 init/main.c:1371 do_initcalls+0x4b/0x8a init/main.c:1387 kernel_init_freeable+0x3fa/0x5ac init/main.c:1626 page_owner free stack trace missing Memory state around the buggy address: ffff88802e8c4580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88802e8c4600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88802e8c4680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802e8c4700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88802e8c4780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================