el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 dccp_parse_options: DCCP(000000005314dd59): Option 32 (len=7) error=9 ================================================================== BUG: KASAN: use-after-free in dccp_ackvec_runlen net/dccp/ackvec.h:43 [inline] BUG: KASAN: use-after-free in ccid2_hc_tx_packet_recv+0x14b8/0x1b04 net/dccp/ccids/ccid2.c:592 Read of size 1 at addr ffff0000d51664a2 by task syz.3.99/4801 CPU: 1 PID: 4801 Comm: syz.3.99 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025 Call trace: dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165 __dump_stack+0x30/0x40 lib/dump_stack.c:88 dump_stack_lvl+0xf8/0x160 lib/dump_stack.c:106 print_address_description+0x88/0x218 mm/kasan/report.c:316 print_report+0x50/0x68 mm/kasan/report.c:420 kasan_report+0xa8/0x100 mm/kasan/report.c:524 __asan_report_load1_noabort+0x2c/0x38 mm/kasan/report_generic.c:348 dccp_ackvec_runlen net/dccp/ackvec.h:43 [inline] ccid2_hc_tx_packet_recv+0x14b8/0x1b04 net/dccp/ccids/ccid2.c:592 ccid_hc_tx_packet_recv net/dccp/ccid.h:189 [inline] dccp_deliver_input_to_ccids net/dccp/input.c:182 [inline] dccp_rcv_established+0x26c/0x2d8 net/dccp/input.c:374 dccp_v6_do_rcv+0x270/0x96c net/dccp/ipv6.c:622 sk_backlog_rcv include/net/sock.h:1125 [inline] __release_sock+0x19c/0x3a0 net/core/sock.c:2944 release_sock+0x60/0x1bc net/core/sock.c:3508 dccp_sendmsg+0x4b8/0x938 net/dccp/proto.c:800 inet_sendmsg+0x154/0x284 net/ipv4/af_inet.c:841 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:730 [inline] ____sys_sendmsg+0x5b8/0x918 net/socket.c:2519 ___sys_sendmsg net/socket.c:2573 [inline] __sys_sendmmsg+0x2f8/0x754 net/socket.c:2659 __do_sys_sendmmsg net/socket.c:2688 [inline] __se_sys_sendmmsg net/socket.c:2685 [inline] __arm64_sys_sendmmsg+0xa0/0xbc net/socket.c:2685 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 Allocated by task 4801: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4c/0x80 mm/kasan/common.c:52 kasan_save_alloc_info+0x28/0x34 mm/kasan/generic.c:505 ____kasan_kmalloc mm/kasan/common.c:374 [inline] __kasan_kmalloc+0xa0/0xb8 mm/kasan/common.c:383 kasan_kmalloc include/linux/kasan.h:211 [inline] __do_kmalloc_node mm/slab_common.c:936 [inline] __kmalloc_node_track_caller+0xe0/0x16c mm/slab_common.c:956 kmalloc_reserve net/core/skbuff.c:446 [inline] __alloc_skb+0x264/0x718 net/core/skbuff.c:515 alloc_skb include/linux/skbuff.h:1271 [inline] dccp_send_ack+0xa4/0x28c net/dccp/output.c:585 ccid2_hc_rx_packet_recv+0x114/0x1b0 net/dccp/ccids/ccid2.c:771 ccid_hc_rx_packet_recv net/dccp/ccid.h:182 [inline] dccp_deliver_input_to_ccids net/dccp/input.c:176 [inline] dccp_rcv_established+0x1ac/0x2d8 net/dccp/input.c:374 dccp_v6_do_rcv+0x270/0x96c net/dccp/ipv6.c:622 sk_backlog_rcv include/net/sock.h:1125 [inline] __sk_receive_skb+0x3d0/0x864 net/core/sock.c:569 dccp_v6_rcv+0xb6c/0x1074 net/dccp/ipv6.c:791 ip6_protocol_deliver_rcu+0x928/0x11d0 net/ipv6/ip6_input.c:438 ip6_input_finish+0x164/0x298 net/ipv6/ip6_input.c:483 NF_HOOK+0x2c4/0x358 include/linux/netfilter.h:302 ip6_input+0x90/0xa8 net/ipv6/ip6_input.c:492 dst_input include/net/dst.h:463 [inline] ip6_rcv_finish+0x1f4/0x220 net/ipv6/ip6_input.c:79 NF_HOOK+0x2c4/0x358 include/linux/netfilter.h:302 ipv6_rcv+0x9c/0xbc net/ipv6/ip6_input.c:310 __netif_receive_skb_one_core net/core/dev.c:5581 [inline] __netif_receive_skb+0xcc/0x2ac net/core/dev.c:5695 process_backlog+0x408/0x714 net/core/dev.c:6023 __napi_poll+0xb4/0x3f0 net/core/dev.c:6590 napi_poll net/core/dev.c:6657 [inline] net_rx_action+0x50c/0xb10 net/core/dev.c:6771 handle_softirqs+0x318/0xc6c kernel/softirq.c:596 __do_softirq+0x14/0x20 kernel/softirq.c:630 Freed by task 4801: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4c/0x80 mm/kasan/common.c:52 kasan_save_free_info+0x3c/0x60 mm/kasan/generic.c:516 ____kasan_slab_free+0x148/0x1b0 mm/kasan/common.c:236 __kasan_slab_free+0x18/0x28 mm/kasan/common.c:244 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1729 [inline] slab_free_freelist_hook+0x16c/0x1ec mm/slub.c:1755 slab_free mm/slub.c:3687 [inline] __kmem_cache_free+0xc0/0x224 mm/slub.c:3700 kfree+0xd0/0x1ac mm/slab_common.c:988 skb_free_head net/core/skbuff.c:762 [inline] skb_release_data+0x43c/0x648 net/core/skbuff.c:791 skb_release_all net/core/skbuff.c:856 [inline] __kfree_skb net/core/skbuff.c:870 [inline] kfree_skb_reason+0x198/0x41c net/core/skbuff.c:893 kfree_skb include/linux/skbuff.h:1220 [inline] dccp_v6_do_rcv+0x12c/0x96c net/dccp/ipv6.c:-1 sk_backlog_rcv include/net/sock.h:1125 [inline] __release_sock+0x19c/0x3a0 net/core/sock.c:2944 release_sock+0x60/0x1bc net/core/sock.c:3508 dccp_sendmsg+0x4b8/0x938 net/dccp/proto.c:800 inet_sendmsg+0x154/0x284 net/ipv4/af_inet.c:841 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:730 [inline] ____sys_sendmsg+0x5b8/0x918 net/socket.c:2519 ___sys_sendmsg net/socket.c:2573 [inline] __sys_sendmmsg+0x2f8/0x754 net/socket.c:2659 __do_sys_sendmmsg net/socket.c:2688 [inline] __se_sys_sendmmsg net/socket.c:2685 [inline] __arm64_sys_sendmmsg+0xa0/0xbc net/socket.c:2685 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 Last potentially related work creation: kasan_save_stack+0x40/0x70 mm/kasan/common.c:45 __kasan_record_aux_stack+0xc0/0xdc mm/kasan/generic.c:486 kasan_record_aux_stack_noalloc+0x14/0x20 mm/kasan/generic.c:496 call_rcu+0x100/0x954 kernel/rcu/tree.c:2849 netlink_release+0x1260/0x1710 net/netlink/af_netlink.c:799 __sock_release net/socket.c:654 [inline] sock_close+0xb4/0x1f8 net/socket.c:1400 __fput+0x1bc/0x7c0 fs/file_table.c:320 ____fput+0x20/0x30 fs/file_table.c:348 task_work_run+0x1ec/0x270 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] do_notify_resume+0x2038/0x2b28 arch/arm64/kernel/signal.c:1137 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline] exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline] el0_svc+0x98/0x138 arch/arm64/kernel/entry-common.c:638 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 The buggy address belongs to the object at ffff0000d5166000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1186 bytes inside of 2048-byte region [ffff0000d5166000, ffff0000d5166800) The buggy address belongs to the physical page: page:000000004e1cf746 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x115160 head:000000004e1cf746 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff) raw: 05ffc00000010200 fffffc0003270600 dead000000000002 ffff0000c0002900 raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000d5166380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000d5166400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff0000d5166480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff0000d5166500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000d5166580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================