================================================================== BUG: KASAN: slab-use-after-free in __lock_acquire+0xff/0x7c80 kernel/locking/lockdep.c:5005 Read of size 8 at addr ffff88807b225cb8 by task syz.0.17/5950 CPU: 1 PID: 5950 Comm: syz.0.17 Not tainted 6.6.102-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:364 [inline] print_report+0xac/0x220 mm/kasan/report.c:468 kasan_report+0x117/0x150 mm/kasan/report.c:581 __lock_acquire+0xff/0x7c80 kernel/locking/lockdep.c:5005 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa8/0xf0 kernel/locking/spinlock.c:162 remove_wait_queue+0x24/0x120 kernel/sched/wait.c:54 free_poll_entry fs/select.c:132 [inline] poll_freewait+0xb1/0x240 fs/select.c:141 do_select+0x175b/0x1840 fs/select.c:609 core_sys_select+0x71c/0x950 fs/select.c:678 do_pselect fs/select.c:760 [inline] __do_sys_pselect6 fs/select.c:801 [inline] __se_sys_pselect6+0x285/0x310 fs/select.c:792 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f17c1f8ebe9 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:00007f17c2e85038 EFLAGS: 00000246 ORIG_RAX: 000000000000010e RAX: ffffffffffffffda RBX: 00007f17c21b5fa0 RCX: 00007f17c1f8ebe9 RDX: 0000000000000000 RSI: 0000200000000100 RDI: 0000000000000040 RBP: 00007f17c2011e19 R08: 0000000000000000 R09: 0000000000000000 R10: 00002000000002c0 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f17c21b6038 R14: 00007f17c21b5fa0 R15: 00007ffe2dd59ce8 Allocated by task 5950: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:52 ____kasan_kmalloc mm/kasan/common.c:374 [inline] __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:383 kmalloc include/linux/slab.h:600 [inline] kzalloc include/linux/slab.h:721 [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_device_attach+0x533/0x660 drivers/comedi/drivers.c:1000 do_devconfig_ioctl drivers/comedi/comedi_fops.c:855 [inline] comedi_unlocked_ioctl+0x68d/0xf90 drivers/comedi/comedi_fops.c:2156 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Freed by task 5951: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:52 kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236 kasan_slab_free include/linux/kasan.h:164 [inline] slab_free_hook mm/slub.c:1806 [inline] slab_free_freelist_hook+0x130/0x1b0 mm/slub.c:1832 slab_free mm/slub.c:3816 [inline] __kmem_cache_free+0xba/0x1f0 mm/slub.c:3829 comedi_device_detach_cleanup drivers/comedi/drivers.c:171 [inline] comedi_device_detach+0x363/0x6f0 drivers/comedi/drivers.c:207 do_devconfig_ioctl drivers/comedi/comedi_fops.c:833 [inline] comedi_unlocked_ioctl+0xbd0/0xf90 drivers/comedi/comedi_fops.c:2156 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 The buggy address belongs to the object at ffff88807b225c00 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 184 bytes inside of freed 256-byte region [ffff88807b225c00, ffff88807b225d00) The buggy address belongs to the physical page: page:ffffea0001ec8900 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7b224 head:ffffea0001ec8900 order:1 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff) page_type: 0xffffffff() raw: 00fff00000000840 ffff888017841b40 dead000000000122 0000000000000000 raw: 0000000000000000 0000000080100010 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 0x152820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_HARDWALL), pid 1094, tgid 1094 (kworker/u4:7), ts 78313279443, free_ts 78228037751 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x1cd/0x210 mm/page_alloc.c:1554 prep_new_page mm/page_alloc.c:1561 [inline] get_page_from_freelist+0x195c/0x19f0 mm/page_alloc.c:3191 __alloc_pages+0x1e3/0x460 mm/page_alloc.c:4457 __alloc_pages_node include/linux/gfp.h:237 [inline] alloc_slab_page+0x4f/0x170 mm/slub.c:1878 allocate_slab mm/slub.c:2023 [inline] new_slab+0x87/0x2e0 mm/slub.c:2076 ___slab_alloc+0xc6d/0x12f0 mm/slub.c:3230 __slab_alloc mm/slub.c:3329 [inline] __slab_alloc_node mm/slub.c:3382 [inline] slab_alloc_node mm/slub.c:3475 [inline] __kmem_cache_alloc_node+0x1a2/0x260 mm/slub.c:3524 __do_kmalloc_node mm/slab_common.c:1006 [inline] __kmalloc_node+0xa4/0x230 mm/slab_common.c:1014 kmalloc_array_node include/linux/slab.h:698 [inline] kcalloc_node include/linux/slab.h:703 [inline] memcg_alloc_slab_cgroups+0x87/0x130 mm/memcontrol.c:2899 account_slab mm/slab.h:641 [inline] allocate_slab mm/slub.c:2041 [inline] new_slab+0xc3/0x2e0 mm/slub.c:2076 ___slab_alloc+0xc6d/0x12f0 mm/slub.c:3230 __slab_alloc mm/slub.c:3329 [inline] __slab_alloc_node mm/slub.c:3382 [inline] slab_alloc_node mm/slub.c:3475 [inline] slab_alloc mm/slub.c:3493 [inline] __kmem_cache_alloc_lru mm/slub.c:3500 [inline] kmem_cache_alloc+0x1b7/0x2e0 mm/slub.c:3509 kmem_cache_zalloc include/linux/slab.h:711 [inline] node_alloc net/ipv6/ip6_fib.c:186 [inline] fib6_add_1+0xa28/0x1430 net/ipv6/ip6_fib.c:882 fib6_add+0x1da/0x3d20 net/ipv6/ip6_fib.c:1404 __ip6_ins_rt net/ipv6/route.c:1343 [inline] ip6_ins_rt+0xc9/0x120 net/ipv6/route.c:1353 __ipv6_ifa_notify+0x62f/0xaa0 net/ipv6/addrconf.c:6247 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1154 [inline] free_unref_page_prepare+0x7ce/0x8e0 mm/page_alloc.c:2336 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2429 __slab_free+0x35e/0x410 mm/slub.c:3722 qlink_free mm/kasan/quarantine.c:166 [inline] qlist_free_all+0x75/0xe0 mm/kasan/quarantine.c:185 kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:305 kasan_slab_alloc include/linux/kasan.h:188 [inline] slab_post_alloc_hook+0x6e/0x4d0 mm/slab.h:767 slab_alloc_node mm/slub.c:3485 [inline] kmem_cache_alloc_node+0x150/0x330 mm/slub.c:3530 __alloc_skb+0x108/0x2c0 net/core/skbuff.c:640 alloc_skb include/linux/skbuff.h:1284 [inline] nlmsg_new include/net/netlink.h:999 [inline] inet_netconf_notify_devconf+0x173/0x230 net/ipv4/devinet.c:2150 __devinet_sysctl_unregister net/ipv4/devinet.c:2661 [inline] devinet_exit_net+0x111/0x220 net/ipv4/devinet.c:2801 ops_exit_list net/core/net_namespace.c:173 [inline] cleanup_net+0x6f4/0xb90 net/core/net_namespace.c:652 process_one_work kernel/workqueue.c:2634 [inline] process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 Memory state around the buggy address: ffff88807b225b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88807b225c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88807b225c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807b225d00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88807b225d80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================