================================================================== BUG: KASAN: slab-out-of-bounds in fib6_add_rt2node+0x369c/0x3bc0 net/ipv6/ip6_fib.c:1142 Read of size 1 at addr ffff888029d918de by task syz.0.4133/21606 CPU: 0 UID: 0 PID: 21606 Comm: syz.0.4133 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x156/0x4c9 mm/kasan/report.c:482 kasan_report+0xdf/0x1a0 mm/kasan/report.c:595 fib6_add_rt2node+0x369c/0x3bc0 net/ipv6/ip6_fib.c:1142 fib6_add_rt2node_nh net/ipv6/ip6_fib.c:1363 [inline] fib6_add+0x3fe/0x1d20 net/ipv6/ip6_fib.c:1531 __ip6_ins_rt net/ipv6/route.c:1351 [inline] ip6_route_add+0xf9/0x1d0 net/ipv6/route.c:3957 inet6_rtm_newroute+0x157/0x160 net/ipv6/route.c:5660 rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:6958 netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xa54/0xc30 net/socket.c:2592 ___sys_sendmsg+0x190/0x1e0 net/socket.c:2646 __sys_sendmsg+0x170/0x220 net/socket.c:2678 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fcd0af9aeb9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fcd0be77028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fcd0b215fa0 RCX: 00007fcd0af9aeb9 RDX: 0000000000000000 RSI: 0000200000004380 RDI: 0000000000000003 RBP: 00007fcd0b008c1f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fcd0b216038 R14: 00007fcd0b215fa0 R15: 00007ffd056a5338 Allocated by task 19972: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5657 [inline] __kmalloc_noprof+0x347/0x9c0 mm/slub.c:5669 kmalloc_noprof include/linux/slab.h:961 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] fib6_info_alloc+0x40/0x160 net/ipv6/ip6_fib.c:155 ip6_route_info_create+0x14c/0xad0 net/ipv6/route.c:3820 ip6_route_add+0x4b/0x1d0 net/ipv6/route.c:3949 inet6_rtm_newroute+0x157/0x160 net/ipv6/route.c:5660 rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:6958 netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xa54/0xc30 net/socket.c:2592 ___sys_sendmsg+0x190/0x1e0 net/socket.c:2646 __sys_sendmsg+0x170/0x220 net/socket.c:2678 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888029d91800 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 22 bytes to the right of allocated 200-byte region [ffff888029d91800, ffff888029d918c8) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888029d90c00 pfn:0x29d90 head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000240 ffff88813fe26b40 ffffea000186ed10 ffffea0001e34e90 raw: ffff888029d90c00 0000000000100005 00000000f5000000 0000000000000000 head: 00fff00000000240 ffff88813fe26b40 ffffea000186ed10 ffffea0001e34e90 head: ffff888029d90c00 0000000000100005 00000000f5000000 0000000000000000 head: 00fff00000000001 ffffea0000a76401 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002 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 5807, tgid 5807 (syz-executor), ts 69891399286, free_ts 69884851960 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1e1/0x250 mm/page_alloc.c:1884 prep_new_page mm/page_alloc.c:1892 [inline] get_page_from_freelist+0xe3d/0x2e10 mm/page_alloc.c:3945 __alloc_frozen_pages_noprof+0x26c/0x2410 mm/page_alloc.c:5240 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2486 alloc_slab_page mm/slub.c:3075 [inline] allocate_slab mm/slub.c:3248 [inline] new_slab+0x2c4/0x440 mm/slub.c:3302 ___slab_alloc+0xda3/0x1ca0 mm/slub.c:4656 __slab_alloc.isra.0+0x63/0x110 mm/slub.c:4779 __slab_alloc_node mm/slub.c:4855 [inline] slab_alloc_node mm/slub.c:5251 [inline] __do_kmalloc_node mm/slub.c:5656 [inline] __kmalloc_noprof+0x618/0x9c0 mm/slub.c:5669 kmalloc_noprof include/linux/slab.h:961 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] fib_create_info+0x5bf/0x4640 net/ipv4/fib_semantics.c:1402 fib_table_insert+0x169/0x1c70 net/ipv4/fib_trie.c:1212 fib_magic+0x4d4/0x5c0 net/ipv4/fib_frontend.c:1134 fib_add_ifaddr+0x4ba/0x560 net/ipv4/fib_frontend.c:1178 fib_netdev_event+0x3d6/0x710 net/ipv4/fib_frontend.c:1516 notifier_call_chain+0x99/0x3b0 kernel/notifier.c:85 call_netdevice_notifiers_info+0xbe/0x110 net/core/dev.c:2243 call_netdevice_notifiers_extack net/core/dev.c:2281 [inline] call_netdevice_notifiers net/core/dev.c:2295 [inline] __dev_notify_flags+0x12c/0x2e0 net/core/dev.c:9788 page last free pid 13 tgid 13 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1433 [inline] __free_frozen_pages+0x822/0x1130 mm/page_alloc.c:2973 discard_slab mm/slub.c:3346 [inline] __put_partials+0x127/0x160 mm/slub.c:3886 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x47/0xe0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5263 [inline] __kmalloc_cache_noprof+0x2e1/0x810 mm/slub.c:5775 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] ipv6_add_addr+0x536/0x1fb0 net/ipv6/addrconf.c:1120 addrconf_add_linklocal+0x2a5/0x500 net/ipv6/addrconf.c:3311 addrconf_addr_gen+0x364/0x3b0 net/ipv6/addrconf.c:3442 addrconf_dev_config net/ipv6/addrconf.c:3489 [inline] addrconf_init_auto_addrs+0x1cb/0x780 net/ipv6/addrconf.c:3567 addrconf_notify+0x9aa/0x19c0 net/ipv6/addrconf.c:3740 notifier_call_chain+0x99/0x3b0 kernel/notifier.c:85 call_netdevice_notifiers_info+0xbe/0x110 net/core/dev.c:2243 netif_state_change+0x165/0x380 net/core/dev.c:1597 linkwatch_do_dev net/core/link_watch.c:186 [inline] linkwatch_do_dev+0xdb/0x110 net/core/link_watch.c:166 __linkwatch_run_queue+0x3a9/0x900 net/core/link_watch.c:240 Memory state around the buggy address: ffff888029d91780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888029d91800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff888029d91880: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc ^ ffff888029d91900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888029d91980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================