================================================================== 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 ffff88807a32bc06 by task syz.3.1692/10353 CPU: 1 PID: 10353 Comm: syz.3.1692 Not tainted 6.6.99-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/0x200 mm/kasan/report.c:466 kasan_report+0x117/0x150 mm/kasan/report.c:579 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 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_connectx net/sctp/socket.c:1336 [inline] sctp_getsockopt_connectx3+0x2c7/0x440 net/sctp/socket.c:1421 sctp_getsockopt+0x986/0xb60 net/sctp/socket.c:8128 do_sock_getsockopt+0x368/0x440 net/socket.c:2384 __sys_getsockopt net/socket.c:2413 [inline] __do_sys_getsockopt net/socket.c:2423 [inline] __se_sys_getsockopt net/socket.c:2420 [inline] __x64_sys_getsockopt+0x1d6/0x280 net/socket.c:2420 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: 0033:0x7fd97ef8e9a9 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:00007fd97fda6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000037 RAX: ffffffffffffffda RBX: 00007fd97f1b5fa0 RCX: 00007fd97ef8e9a9 RDX: 000000000000006f RSI: 0000000000000084 RDI: 0000000000000003 RBP: 00007fd97f010d69 R08: 0000200000000180 R09: 0000000000000000 R10: 00002000000006c0 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fd97f1b5fa0 R15: 00007ffe4a2b79f8 Allocated by task 10237: 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] slab_alloc mm/slub.c:3493 [inline] __kmem_cache_alloc_lru mm/slub.c:3500 [inline] kmem_cache_alloc+0x11e/0x2e0 mm/slub.c:3509 getname_flags+0xbb/0x500 fs/namei.c:140 user_path_at_empty+0x2c/0x60 fs/namei.c:2908 do_readlinkat+0xd8/0x480 fs/stat.c:494 __do_sys_readlink fs/stat.c:527 [inline] __se_sys_readlink fs/stat.c:524 [inline] __x64_sys_readlink+0x7f/0x90 fs/stat.c:524 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 10237: 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+0xf8/0x280 mm/slub.c:3838 user_path_at_empty+0x4c/0x60 fs/namei.c:2911 do_readlinkat+0xd8/0x480 fs/stat.c:494 __do_sys_readlink fs/stat.c:527 [inline] __se_sys_readlink fs/stat.c:524 [inline] __x64_sys_readlink+0x7f/0x90 fs/stat.c:524 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 ffff88807a32b300 which belongs to the cache names_cache of size 4096 The buggy address is located 2310 bytes inside of freed 4096-byte region [ffff88807a32b300, ffff88807a32c300) The buggy address belongs to the physical page: page:ffffea0001e8ca00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7a328 head:ffffea0001e8ca00 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff) page_type: 0xffffffff() raw: 00fff00000000840 ffff888019a4d780 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000070007 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 5794, tgid 5794 (udevd), ts 125461324726, free_ts 125408602972 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 getname_flags+0xbb/0x500 fs/namei.c:140 user_path_at_empty+0x2c/0x60 fs/namei.c:2908 do_readlinkat+0xd8/0x480 fs/stat.c:494 __do_sys_readlink fs/stat.c:527 [inline] __se_sys_readlink fs/stat.c:524 [inline] __x64_sys_readlink+0x7f/0x90 fs/stat.c:524 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 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] slab_alloc mm/slub.c:3493 [inline] __kmem_cache_alloc_lru mm/slub.c:3500 [inline] kmem_cache_alloc+0x11e/0x2e0 mm/slub.c:3509 getname_flags+0xbb/0x500 fs/namei.c:140 getname fs/namei.c:219 [inline] __do_sys_unlink fs/namei.c:4439 [inline] __se_sys_unlink fs/namei.c:4437 [inline] __x64_sys_unlink+0x3c/0x50 fs/namei.c:4437 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 Memory state around the buggy address: ffff88807a32bb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807a32bb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88807a32bc00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807a32bc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807a32bd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================