================================================================== BUG: KASAN: use-after-free in string_nocheck lib/vsprintf.c:641 [inline] BUG: KASAN: use-after-free in string+0x21f/0x2b0 lib/vsprintf.c:723 Read of size 1 at addr ffff88810b35ccb9 by task syz.4.1199/4372 CPU: 0 PID: 4372 Comm: syz.4.1199 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2025 Call Trace: __dump_stack+0x21/0x24 lib/dump_stack.c:77 dump_stack_lvl+0x169/0x1d8 lib/dump_stack.c:118 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:435 [inline] kasan_report+0xe2/0x130 mm/kasan/report.c:452 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report_generic.c:306 string_nocheck lib/vsprintf.c:641 [inline] string+0x21f/0x2b0 lib/vsprintf.c:723 vsnprintf+0xf20/0x1960 lib/vsprintf.c:2689 seq_vprintf fs/seq_file.c:398 [inline] seq_printf+0x175/0x260 fs/seq_file.c:413 input_devices_seq_show+0x1a6/0x650 drivers/input/input.c:1186 seq_read_iter+0x93f/0xd30 fs/seq_file.c:272 seq_read+0x3cc/0x4d0 fs/seq_file.c:162 pde_read fs/proc/inode.c:321 [inline] proc_reg_read+0x1c4/0x2b0 fs/proc/inode.c:333 vfs_read+0x1fe/0xa10 fs/read_write.c:494 ksys_read+0x140/0x240 fs/read_write.c:634 __do_sys_read fs/read_write.c:644 [inline] __se_sys_read fs/read_write.c:642 [inline] __x64_sys_read+0x7b/0x90 fs/read_write.c:642 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f82e3d80ba9 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:00007f82e27e9038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007f82e3fc7fa0 RCX: 00007f82e3d80ba9 RDX: 0000000000002020 RSI: 0000200000004480 RDI: 000000000000000d RBP: 00007f82e3e03e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f82e3fc8038 R14: 00007f82e3fc7fa0 R15: 00007fff712fdbe8 Allocated by task 2304: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:430 [inline] ____kasan_kmalloc mm/kasan/common.c:509 [inline] __kasan_kmalloc+0xda/0x110 mm/kasan/common.c:518 kasan_kmalloc include/linux/kasan.h:254 [inline] __kmalloc+0x1a7/0x330 mm/slub.c:4038 __kmalloc_node include/linux/slab.h:418 [inline] kmalloc_node include/linux/slab.h:575 [inline] kvmalloc_node+0x88/0x130 mm/util.c:612 kvmalloc include/linux/mm.h:833 [inline] kvzalloc include/linux/mm.h:841 [inline] netif_alloc_netdev_queues net/core/dev.c:9911 [inline] alloc_netdev_mqs+0x61e/0xc80 net/core/dev.c:10577 __ip_tunnel_create+0x206/0x380 net/ipv4/ip_tunnel.c:254 ip_tunnel_init_net+0x290/0x740 net/ipv4/ip_tunnel.c:1083 erspan_init_net+0x29/0x30 net/ipv4/ip_gre.c:1718 ops_init+0x1ba/0x4a0 net/core/net_namespace.c:144 setup_net+0x36d/0xb50 net/core/net_namespace.c:345 copy_net_ns+0x314/0x520 net/core/net_namespace.c:486 create_new_namespaces+0x3a2/0x650 kernel/nsproxy.c:110 copy_namespaces+0x1d1/0x220 kernel/nsproxy.c:179 copy_process+0x11b8/0x32c0 kernel/fork.c:2271 kernel_clone+0x23f/0x940 kernel/fork.c:2650 __do_sys_clone kernel/fork.c:2776 [inline] __se_sys_clone kernel/fork.c:2760 [inline] __x64_sys_clone+0x176/0x1d0 kernel/fork.c:2760 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb Last potentially related work creation: kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38 __kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358 kvfree_call_rcu+0x10c/0x620 kernel/rcu/tree.c:3539 neigh_destroy+0x445/0x570 net/core/neighbour.c:865 neigh_release include/net/neighbour.h:427 [inline] neigh_cleanup_and_release+0x76/0x1a0 net/core/neighbour.c:104 neigh_del net/core/neighbour.c:198 [inline] neigh_remove_one+0x341/0x3b0 net/core/neighbour.c:219 neigh_forced_gc net/core/neighbour.c:252 [inline] neigh_alloc net/core/neighbour.c:430 [inline] ___neigh_create+0x48b/0x1a20 net/core/neighbour.c:592 __neigh_create+0x31/0x40 net/core/neighbour.c:680 ip6_finish_output2+0x8d1/0x1500 net/ipv6/ip6_output.c:127 __ip6_finish_output+0x5ff/0x790 net/ipv6/ip6_output.c:201 ip6_finish_output+0x33/0x1f0 net/ipv6/ip6_output.c:211 NF_HOOK_COND include/linux/netfilter.h:288 [inline] ip6_output+0x1d1/0x3b0 net/ipv6/ip6_output.c:234 dst_output include/net/dst.h:451 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ndisc_send_skb+0x6f5/0xb40 net/ipv6/ndisc.c:513 ndisc_send_rs+0x6e5/0x960 net/ipv6/ndisc.c:707 addrconf_dad_completed+0x97f/0xe80 net/ipv6/addrconf.c:4287 addrconf_dad_work+0xc18/0x1410 net/ipv6/addrconf.c:-1 process_one_work+0x6e1/0xba0 kernel/workqueue.c:2301 worker_thread+0xa6a/0x13b0 kernel/workqueue.c:2447 kthread+0x346/0x3d0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 The buggy address belongs to the object at ffff88810b35cc00 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 185 bytes inside of 512-byte region [ffff88810b35cc00, ffff88810b35ce00) The buggy address belongs to the page: page:ffffea00042cd700 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88810b35cc00 pfn:0x10b35c head:ffffea00042cd700 order:2 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head) raw: 4000000000010200 ffffea0004982708 ffffea0004127a08 ffff888100043080 raw: ffff88810b35cc00 000000000010000f 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0x52a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 7, ts 27823573819, free_ts 27725594179 set_page_owner include/linux/page_owner.h:35 [inline] post_alloc_hook mm/page_alloc.c:2456 [inline] prep_new_page+0x179/0x180 mm/page_alloc.c:2462 get_page_from_freelist+0x2235/0x23d0 mm/page_alloc.c:4254 __alloc_pages_nodemask+0x268/0x5f0 mm/page_alloc.c:5370 alloc_slab_page mm/slub.c:-1 [inline] allocate_slab mm/slub.c:1813 [inline] new_slab+0x84/0x3f0 mm/slub.c:1874 new_slab_objects mm/slub.c:2632 [inline] ___slab_alloc+0x2a6/0x450 mm/slub.c:2796 __slab_alloc+0x63/0xa0 mm/slub.c:2836 slab_alloc_node mm/slub.c:2918 [inline] slab_alloc mm/slub.c:2960 [inline] __kmalloc+0x201/0x330 mm/slub.c:4034 kmalloc include/linux/slab.h:557 [inline] kzalloc include/linux/slab.h:664 [inline] fib6_info_alloc+0x34/0xe0 net/ipv6/ip6_fib.c:154 ip6_route_info_create+0x4d2/0x1490 net/ipv6/route.c:3673 ip6_route_add+0x27/0x130 net/ipv6/route.c:3769 addrconf_prefix_route net/ipv6/addrconf.c:2463 [inline] addrconf_add_linklocal+0x3cf/0x620 net/ipv6/addrconf.c:3259 addrconf_addr_gen+0x48b/0x5b0 net/ipv6/addrconf.c:3388 addrconf_dev_config+0x293/0x510 net/ipv6/addrconf.c:3440 addrconf_notify+0x9d8/0xe90 net/ipv6/addrconf.c:3673 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0x90/0x100 kernel/notifier.c:410 call_netdevice_notifiers_info net/core/dev.c:2054 [inline] netdev_state_change+0x16a/0x210 net/core/dev.c:1484 page last free stack trace: reset_page_owner include/linux/page_owner.h:28 [inline] free_pages_prepare mm/page_alloc.c:1349 [inline] __free_pages_ok+0x7fc/0x820 mm/page_alloc.c:1629 free_the_page mm/page_alloc.c:5431 [inline] __free_pages+0xdd/0x380 mm/page_alloc.c:5440 __free_slab+0xcf/0x190 mm/slub.c:1899 free_slab mm/slub.c:1914 [inline] discard_slab mm/slub.c:1920 [inline] unfreeze_partials+0x15f/0x190 mm/slub.c:2415 put_cpu_partial+0xc1/0x180 mm/slub.c:2451 __slab_free+0x2c9/0x3a0 mm/slub.c:3100 do_slab_free mm/slub.c:3196 [inline] ___cache_free+0x111/0x130 mm/slub.c:3215 qlink_free+0x50/0x90 mm/kasan/quarantine.c:157 qlist_free_all+0x5f/0xb0 mm/kasan/quarantine.c:176 kasan_quarantine_reduce+0x14a/0x160 mm/kasan/quarantine.c:283 __kasan_slab_alloc+0x2f/0xf0 mm/kasan/common.c:440 kasan_slab_alloc include/linux/kasan.h:244 [inline] slab_post_alloc_hook+0x5d/0x2f0 mm/slab.h:580 slab_alloc_node mm/slub.c:2952 [inline] slab_alloc mm/slub.c:2960 [inline] kmem_cache_alloc_trace+0x160/0x2e0 mm/slub.c:2977 kmalloc include/linux/slab.h:552 [inline] kzalloc include/linux/slab.h:664 [inline] ____ip_mc_inc_group+0x190/0x820 net/ipv4/igmp.c:1452 __ip_mc_inc_group net/ipv4/igmp.c:1487 [inline] ip_mc_inc_group net/ipv4/igmp.c:1493 [inline] ip_mc_up+0x112/0x1f0 net/ipv4/igmp.c:1792 inetdev_event+0xc13/0x1030 net/ipv4/devinet.c:1587 Memory state around the buggy address: ffff88810b35cb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88810b35cc00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88810b35cc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88810b35cd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88810b35cd80: fb fb fb fb fb 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