==================================================================
BUG: KASAN: slab-out-of-bounds in decode_session6 net/xfrm/xfrm_policy.c:3494 [inline]
BUG: KASAN: slab-out-of-bounds in __xfrm_decode_session+0x18d7/0x20a0 net/xfrm/xfrm_policy.c:3600
Read of size 1 at addr ffff88802eda38bc by task syz.2.461/7353

CPU: 1 PID: 7353 Comm: syz.2.461 Not tainted 6.6.98-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xac/0x230 mm/kasan/report.c:475
 kasan_report+0x117/0x150 mm/kasan/report.c:588
 decode_session6 net/xfrm/xfrm_policy.c:3494 [inline]
 __xfrm_decode_session+0x18d7/0x20a0 net/xfrm/xfrm_policy.c:3600
 xfrm_decode_session_reverse include/net/xfrm.h:1243 [inline]
 icmpv6_route_lookup+0x358/0x590 net/ipv6/icmp.c:392
 icmp6_send+0x106a/0x1990 net/ipv6/icmp.c:604
 __icmpv6_send include/linux/icmpv6.h:28 [inline]
 icmpv6_send include/linux/icmpv6.h:49 [inline]
 ip6_link_failure+0x3b/0x4c0 net/ipv6/route.c:2825
 dst_link_failure include/net/dst.h:437 [inline]
 ip6_tnl_xmit+0xdf7/0x2a30 net/ipv6/ip6_tunnel.c:1283
 ipxip6_tnl_xmit net/ipv6/ip6_tunnel.c:1399 [inline]
 ip6_tnl_start_xmit+0xc10/0x1140 net/ipv6/ip6_tunnel.c:1447
 __netdev_start_xmit include/linux/netdevice.h:4943 [inline]
 netdev_start_xmit include/linux/netdevice.h:4957 [inline]
 xmit_one net/core/dev.c:3607 [inline]
 dev_hard_start_xmit+0x246/0x740 net/core/dev.c:3623
 sch_direct_xmit+0x252/0x4a0 net/sched/sch_generic.c:342
 qdisc_restart net/sched/sch_generic.c:407 [inline]
 __qdisc_run+0xab2/0x1570 net/sched/sch_generic.c:415
 __dev_xmit_skb net/core/dev.c:3907 [inline]
 __dev_queue_xmit+0xf02/0x35a0 net/core/dev.c:4379
 neigh_output include/net/neighbour.h:542 [inline]
 ip6_finish_output2+0xe2e/0x1650 net/ipv6/ip6_output.c:141
 ip6_fragment+0x13c5/0x1f90 net/ipv6/ip6_output.c:1023
 __ip6_finish_output net/ipv6/ip6_output.c:206 [inline]
 ip6_finish_output+0x5b4/0xaf0 net/ipv6/ip6_output.c:219
 dst_output include/net/dst.h:467 [inline]
 NF_HOOK include/linux/netfilter.h:304 [inline]
 ip6_xmit+0x10a7/0x1830 net/ipv6/ip6_output.c:360
 sctp_v6_xmit+0x9e3/0x1230 net/sctp/ipv6.c:250
 sctp_packet_transmit+0x2488/0x2a30 net/sctp/output.c:653
 sctp_packet_singleton+0x234/0x330 net/sctp/outqueue.c:783
 sctp_outq_flush_ctrl net/sctp/outqueue.c:914 [inline]
 sctp_outq_flush+0x4f1/0x3100 net/sctp/outqueue.c:1212
 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:-1 [inline]
 sctp_side_effects net/sctp/sm_sideeffect.c:1198 [inline]
 sctp_do_sm+0x52d6/0x59a0 net/sctp/sm_sideeffect.c:1169
 sctp_primitive_ASSOCIATE+0x95/0xc0 net/sctp/primitive.c:73
 __sctp_connect+0x92f/0xd20 net/sctp/socket.c:1234
 sctp_setsockopt+0x458/0x11e0 net/sctp/socket.c:4617
 do_sock_setsockopt+0x254/0x3e0 net/socket.c:2322
 __sys_setsockopt net/socket.c:2345 [inline]
 __do_sys_setsockopt net/socket.c:2354 [inline]
 __se_sys_setsockopt net/socket.c:2351 [inline]
 __x64_sys_setsockopt+0x1be/0x250 net/socket.c:2351
 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: 0033:0x7fcc3e18e929
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:00007fcc3ef93038 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007fcc3e3b5fa0 RCX: 00007fcc3e18e929
RDX: 000000000000006b RSI: 0000000000000084 RDI: 0000000000000003
RBP: 00007fcc3e210ca1 R08: 000000000000001c R09: 0000000000000000
R10: 0000200000000380 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fcc3e3b5fa0 R15: 00007ffe6d523dc8
 </TASK>

Allocated by task 7353:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:328
 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
 kmalloc_reserve+0x95/0x260 net/core/skbuff.c:559
 __alloc_skb+0x138/0x2c0 net/core/skbuff.c:650
 alloc_skb include/linux/skbuff.h:1284 [inline]
 ip6_frag_next+0x12f/0xb40 net/ipv6/ip6_output.c:801
 ip6_fragment+0x132a/0x1f90 net/ipv6/ip6_output.c:1013
 __ip6_finish_output net/ipv6/ip6_output.c:206 [inline]
 ip6_finish_output+0x5b4/0xaf0 net/ipv6/ip6_output.c:219
 dst_output include/net/dst.h:467 [inline]
 NF_HOOK include/linux/netfilter.h:304 [inline]
 ip6_xmit+0x10a7/0x1830 net/ipv6/ip6_output.c:360
 sctp_v6_xmit+0x9e3/0x1230 net/sctp/ipv6.c:250
 sctp_packet_transmit+0x2488/0x2a30 net/sctp/output.c:653
 sctp_packet_singleton+0x234/0x330 net/sctp/outqueue.c:783
 sctp_outq_flush_ctrl net/sctp/outqueue.c:914 [inline]
 sctp_outq_flush+0x4f1/0x3100 net/sctp/outqueue.c:1212
 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:-1 [inline]
 sctp_side_effects net/sctp/sm_sideeffect.c:1198 [inline]
 sctp_do_sm+0x52d6/0x59a0 net/sctp/sm_sideeffect.c:1169
 sctp_primitive_ASSOCIATE+0x95/0xc0 net/sctp/primitive.c:73
 __sctp_connect+0x92f/0xd20 net/sctp/socket.c:1234
 sctp_setsockopt+0x458/0x11e0 net/sctp/socket.c:4617
 do_sock_setsockopt+0x254/0x3e0 net/socket.c:2322
 __sys_setsockopt net/socket.c:2345 [inline]
 __do_sys_setsockopt net/socket.c:2354 [inline]
 __se_sys_setsockopt net/socket.c:2351 [inline]
 __x64_sys_setsockopt+0x1be/0x250 net/socket.c:2351
 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 ffff88802eda3600
 which belongs to the cache skbuff_small_head of size 640
The buggy address is located 60 bytes to the right of
 allocated 640-byte region [ffff88802eda3600, ffff88802eda3880)

The buggy address belongs to the physical page:
page:ffffea0000bb6800 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2eda0
head:ffffea0000bb6800 order:2 entire_mapcount:0 nr_pages_mapped:0 pincount:0
ksm flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888140051780 ffffea0000b72400 dead000000000003
raw: 0000000000000000 0000000080150015 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5161, tgid 5161 (udevadm), ts 21507079004, free_ts 21505736648
 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_slab_page+0x5d/0x170 mm/slub.c:1876
 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+0x1ea/0x330 mm/slub.c:3530
 kmalloc_reserve+0x95/0x260 net/core/skbuff.c:559
 __alloc_skb+0x138/0x2c0 net/core/skbuff.c:650
 alloc_skb include/linux/skbuff.h:1284 [inline]
 alloc_uevent_skb+0x7d/0x230 lib/kobject_uevent.c:290
 uevent_net_broadcast_untagged lib/kobject_uevent.c:326 [inline]
 kobject_uevent_net_broadcast+0x2e6/0x530 lib/kobject_uevent.c:409
 kobject_uevent_env+0x550/0x8c0 lib/kobject_uevent.c:608
 kobject_synth_uevent+0x524/0xaf0 lib/kobject_uevent.c:208
 store_uevent+0x16/0x20 kernel/module/main.c:916
 module_attr_store+0x5f/0x80 kernel/params.c:920
 kernfs_fop_write_iter+0x37d/0x4d0 fs/kernfs/file.c:334
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
 discard_slab mm/slub.c:2122 [inline]
 __unfreeze_partials+0x1cf/0x210 mm/slub.c:2662
 put_cpu_partial+0x17c/0x250 mm/slub.c:2738
 __slab_free+0x31d/0x410 mm/slub.c:3686
 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]
 netlink_alloc_large_skb net/netlink/af_netlink.c:1195 [inline]
 netlink_sendmsg+0x65b/0xbe0 net/netlink/af_netlink.c:1866
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0x5bf/0x950 net/socket.c:2595
 ___sys_sendmsg+0x220/0x290 net/socket.c:2649
 __sys_sendmsg net/socket.c:2678 [inline]
 __do_sys_sendmsg net/socket.c:2687 [inline]
 __se_sys_sendmsg+0x1a5/0x270 net/socket.c:2685
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81

Memory state around the buggy address:
 ffff88802eda3780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88802eda3800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88802eda3880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                        ^
 ffff88802eda3900: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88802eda3980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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