syzbot

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BUG: KASAN: use-after-free in __xfrm_state_insert+0x8af/0x1450 net/xfrm/xfrm_state.c:1743
Read of size 1 at addr ffff888056ba8bb0 by task syz.2.2485/14095

CPU: 0 UID: 0 PID: 14095 Comm: syz.2.2485 Not tainted 6.16.0-rc7-syzkaller-01904-g9312ee76490d #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x230 mm/kasan/report.c:480
 kasan_report+0x118/0x150 mm/kasan/report.c:593
 __xfrm_state_insert+0x8af/0x1450 net/xfrm/xfrm_state.c:1743
 xfrm_state_insert+0x54/0x60 net/xfrm/xfrm_state.c:1795
 ipcomp6_tunnel_attach net/ipv6/ipcomp6.c:131 [inline]
 ipcomp6_init_state+0x655/0x900 net/ipv6/ipcomp6.c:163
 __xfrm_init_state+0xa73/0x13f0 net/xfrm/xfrm_state.c:3188
 xfrm_init_state+0x18/0xa0 net/xfrm/xfrm_state.c:3231
 pfkey_msg2xfrm_state net/key/af_key.c:1286 [inline]
 pfkey_add+0x1d38/0x2e00 net/key/af_key.c:1504
 pfkey_process net/key/af_key.c:2848 [inline]
 pfkey_sendmsg+0xbfe/0x1090 net/key/af_key.c:3699
 sock_sendmsg_nosec net/socket.c:714 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:729
 ____sys_sendmsg+0x505/0x830 net/socket.c:2614
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2668
 __sys_sendmsg net/socket.c:2700 [inline]
 __do_sys_sendmsg net/socket.c:2705 [inline]
 __se_sys_sendmsg net/socket.c:2703 [inline]
 __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2703
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f91e0d8e9a9
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:00007f91e1bc9038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f91e0fb5fa0 RCX: 00007f91e0d8e9a9
RDX: 0000000000000000 RSI: 00002000000001c0 RDI: 0000000000000004
RBP: 00007f91e0e10d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f91e0fb5fa0 R15: 00007ffd4df147d8
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888056babc00 pfn:0x56ba8
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0000c65608 ffffea0001b7c408 0000000000000000
raw: ffff888056babc00 0000000000100000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 13250, tgid 13248 (syz.1.2213), ts 301636788674, free_ts 323874401753
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1704
 prep_new_page mm/page_alloc.c:1712 [inline]
 get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3669
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4959
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2419
 alloc_slab_page mm/slub.c:2451 [inline]
 allocate_slab+0x8a/0x3b0 mm/slub.c:2619
 new_slab mm/slub.c:2673 [inline]
 ___slab_alloc+0xbfc/0x1480 mm/slub.c:3859
 __slab_alloc mm/slub.c:3949 [inline]
 __slab_alloc_node mm/slub.c:4024 [inline]
 slab_alloc_node mm/slub.c:4185 [inline]
 __do_kmalloc_node mm/slub.c:4327 [inline]
 __kmalloc_noprof+0x305/0x4f0 mm/slub.c:4340
 kmalloc_noprof include/linux/slab.h:909 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 copy_splice_read+0x143/0x9b0 fs/splice.c:337
 do_splice_read fs/splice.c:978 [inline]
 splice_direct_to_actor+0x4d0/0xcc0 fs/splice.c:1083
 do_splice_direct_actor fs/splice.c:1201 [inline]
 do_splice_direct+0x181/0x270 fs/splice.c:1227
 do_sendfile+0x4da/0x7e0 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64+0x13e/0x190 fs/read_write.c:1417
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5853 tgid 5853 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1248 [inline]
 __free_frozen_pages+0xc71/0xe70 mm/page_alloc.c:2706
 discard_slab mm/slub.c:2717 [inline]
 __put_partials+0x161/0x1c0 mm/slub.c:3186
 put_cpu_partial+0x17c/0x250 mm/slub.c:3261
 __slab_free+0x2f7/0x400 mm/slub.c:4513
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4148 [inline]
 slab_alloc_node mm/slub.c:4197 [inline]
 __do_kmalloc_node mm/slub.c:4327 [inline]
 __kmalloc_node_noprof+0x21b/0x4e0 mm/slub.c:4334
 kmalloc_node_noprof include/linux/slab.h:932 [inline]
 __vmalloc_area_node mm/vmalloc.c:3698 [inline]
 __vmalloc_node_range_noprof+0x5a9/0x12f0 mm/vmalloc.c:3893
 __vmalloc_node_noprof mm/vmalloc.c:3956 [inline]
 vzalloc_noprof+0xb2/0xf0 mm/vmalloc.c:4030
 alloc_counters+0xd3/0x6d0 net/ipv4/netfilter/ip_tables.c:799
 copy_entries_to_user net/ipv6/netfilter/ip6_tables.c:837 [inline]
 get_entries net/ipv6/netfilter/ip6_tables.c:1039 [inline]
 do_ip6t_get_ctl+0xa94/0x1180 net/ipv6/netfilter/ip6_tables.c:1677
 nf_getsockopt+0x26b/0x290 net/netfilter/nf_sockopt.c:116
 ipv6_getsockopt+0x1ed/0x290 net/ipv6/ipv6_sockglue.c:1469
 do_sock_getsockopt+0x36f/0x450 net/socket.c:2405
 __sys_getsockopt net/socket.c:2434 [inline]
 __do_sys_getsockopt net/socket.c:2441 [inline]
 __se_sys_getsockopt net/socket.c:2438 [inline]
 __x64_sys_getsockopt+0x1a5/0x250 net/socket.c:2438

Memory state around the buggy address:
 ffff888056ba8a80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888056ba8b00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888056ba8b80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                     ^
 ffff888056ba8c00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888056ba8c80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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