================================================================== BUG: KASAN: slab-use-after-free in decode_session6 net/xfrm/xfrm_policy.c:3494 [inline] BUG: KASAN: slab-use-after-free in __xfrm_decode_session+0x18d7/0x20a0 net/xfrm/xfrm_policy.c:3600 Read of size 1 at addr ffff88801e7d2178 by task syz.5.2891/18451 CPU: 0 PID: 18451 Comm: syz.5.2891 Not tainted 6.6.95-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:364 [inline] print_report+0xac/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_sendmsg_to_asoc+0x101c/0x17f0 net/sctp/socket.c:1841 sctp_sendmsg+0x1941/0x27e0 net/sctp/socket.c:2031 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] __sys_sendto+0x46a/0x620 net/socket.c:2201 __do_sys_sendto net/socket.c:2213 [inline] __se_sys_sendto net/socket.c:2209 [inline] __x64_sys_sendto+0xde/0xf0 net/socket.c:2209 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: 0033:0x7fe476b8e929 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:00007fe477a6a038 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007fe476db5fa0 RCX: 00007fe476b8e929 RDX: 0000000000000001 RSI: 0000200000000000 RDI: 0000000000000003 RBP: 00007fe476c10b39 R08: 00002000000000c0 R09: 000000000000001c R10: 0000000000000051 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fe476db5fa0 R15: 00007ffcd1191658 Allocated by task 5976: 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 __alloc_skb+0x108/0x2c0 net/core/skbuff.c:640 alloc_skb include/linux/skbuff.h:1284 [inline] nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:748 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:805 [inline] nsim_dev_trap_report_work+0x293/0xb00 drivers/net/netdevsim/dev.c:851 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 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 The buggy address belongs to the object at ffff88801e7d2140 which belongs to the cache skbuff_head_cache of size 240 The buggy address is located 56 bytes inside of freed 240-byte region [ffff88801e7d2140, ffff88801e7d2230) The buggy address belongs to the physical page: page:ffffea000079f480 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88801e7d2140 pfn:0x1e7d2 memcg:ffff88802bcbe481 flags: 0xfff00000000800(slab|node=0|zone=1|lastcpupid=0x7ff) page_type: 0xffffffff() raw: 00fff00000000800 ffff88814007f500 ffffea0001de08d0 ffffea000168a150 raw: ffff88801e7d2140 00000000000c0007 00000001ffffffff ffff88802bcbe481 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL), pid 13153, tgid 13133 (syz.1.1316), ts 1005280437825, free_ts 1005085074661 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] 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 skb_clone+0x1eb/0x370 net/core/skbuff.c:1911 __skb_tstamp_tx+0x185/0x9d0 net/core/skbuff.c:5318 skb_tx_timestamp include/linux/skbuff.h:4414 [inline] tun_net_xmit+0xada/0x15e0 drivers/net/tun.c:1124 __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 __dev_xmit_skb net/core/dev.c:3844 [inline] __dev_queue_xmit+0x173e/0x35a0 net/core/dev.c:4379 dev_queue_xmit include/linux/netdevice.h:3113 [inline] neigh_hh_output include/net/neighbour.h:526 [inline] neigh_output include/net/neighbour.h:540 [inline] ip_finish_output2+0xcd3/0x11d0 net/ipv4/ip_output.c:235 dst_output include/net/dst.h:467 [inline] ip_local_out net/ipv4/ip_output.c:129 [inline] ip_send_skb+0x12d/0x1d0 net/ipv4/ip_output.c:1491 udp_send_skb+0xa37/0x13a0 net/ipv4/udp.c:984 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] nlmsg_new include/net/netlink.h:999 [inline] genlmsg_new include/net/genetlink.h:554 [inline] reset_per_cpu_data+0x31/0x1e0 net/core/drop_monitor.c:145 send_dm_alert+0x1f/0xe0 net/core/drop_monitor.c:196 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 Memory state around the buggy address: ffff88801e7d2000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88801e7d2080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc >ffff88801e7d2100: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ^ ffff88801e7d2180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88801e7d2200: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc ==================================================================