RDX: 0000000000000500 RSI: 00000000200001c0 RDI: 0000000000000005 RBP: 00007f5c095cf0a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002 R13: 000000000000000b R14: 00007f5c08903f60 R15: 00007ffc5cfa8758 dccp_parse_options: DCCP(ffff888064773700): Option 32 (len=7) error=9 ================================================================== BUG: KASAN: slab-use-after-free in dccp_ackvec_runlen net/dccp/ackvec.h:43 [inline] BUG: KASAN: slab-use-after-free in ccid2_hc_tx_packet_recv+0x1902/0x2070 net/dccp/ccids/ccid2.c:593 Read of size 1 at addr ffff888065be34a2 by task syz.0.16/6691 CPU: 0 UID: 0 PID: 6691 Comm: syz.0.16 Not tainted 6.14.0-rc5-syzkaller-g2e51e0ac575c #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0x16e/0x5b0 mm/kasan/report.c:521 kasan_report+0x143/0x180 mm/kasan/report.c:634 dccp_ackvec_runlen net/dccp/ackvec.h:43 [inline] ccid2_hc_tx_packet_recv+0x1902/0x2070 net/dccp/ccids/ccid2.c:593 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+0x295/0x320 net/dccp/input.c:374 dccp_v6_do_rcv+0x2c9/0xb80 net/dccp/ipv6.c:625 sk_backlog_rcv include/net/sock.h:1122 [inline] __release_sock+0x243/0x350 net/core/sock.c:3123 release_sock+0x61/0x1f0 net/core/sock.c:3677 dccp_sendmsg+0x4f0/0xb90 net/dccp/proto.c:803 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg+0x1a6/0x270 net/socket.c:733 ____sys_sendmsg+0x53a/0x860 net/socket.c:2573 ___sys_sendmsg net/socket.c:2627 [inline] __sys_sendmmsg+0x36a/0x720 net/socket.c:2716 __do_sys_sendmmsg net/socket.c:2743 [inline] __se_sys_sendmmsg net/socket.c:2740 [inline] __x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2740 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5c08775bd9 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:00007f5c095cf048 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007f5c08903f60 RCX: 00007f5c08775bd9 RDX: 0000000000000500 RSI: 00000000200001c0 RDI: 0000000000000005 RBP: 00007f5c095cf0a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002 R13: 000000000000000b R14: 00007f5c08903f60 R15: 00007ffc5cfa8758 Allocated by task 6691: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4294 [inline] __kmalloc_node_track_caller_noprof+0x28b/0x4c0 mm/slub.c:4313 kmalloc_reserve+0x111/0x2a0 net/core/skbuff.c:537 __alloc_skb+0x1f3/0x440 net/core/skbuff.c:606 alloc_skb include/linux/skbuff.h:1331 [inline] dccp_send_ack+0xaa/0x310 net/dccp/output.c:585 ccid2_hc_rx_packet_recv+0x10c/0x1c0 net/dccp/ccids/ccid2.c:772 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+0x1bb/0x320 net/dccp/input.c:374 dccp_v6_do_rcv+0x2c9/0xb80 net/dccp/ipv6.c:625 sk_backlog_rcv include/net/sock.h:1122 [inline] __sk_receive_skb+0x82b/0x8b0 net/core/sock.c:575 dccp_v6_rcv+0x1189/0x1640 net/dccp/ipv6.c:794 ip6_protocol_deliver_rcu+0x105b/0x1580 net/ipv6/ip6_input.c:436 ip6_input_finish+0xdd/0x190 net/ipv6/ip6_input.c:480 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314 ip6_input+0x169/0x270 net/ipv6/ip6_input.c:491 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314 __netif_receive_skb_one_core net/core/dev.c:5893 [inline] __netif_receive_skb+0x1ea/0x650 net/core/dev.c:6006 process_backlog+0x662/0x15b0 net/core/dev.c:6354 __napi_poll+0xcb/0x490 net/core/dev.c:7188 napi_poll net/core/dev.c:7257 [inline] net_rx_action+0x89b/0x1240 net/core/dev.c:7379 handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561 do_softirq+0x11b/0x1e0 kernel/softirq.c:462 __local_bh_enable_ip+0x1bb/0x200 kernel/softirq.c:389 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:919 [inline] __dev_queue_xmit+0x1775/0x3f50 net/core/dev.c:4676 dev_queue_xmit include/linux/netdevice.h:3313 [inline] neigh_hh_output include/net/neighbour.h:523 [inline] neigh_output include/net/neighbour.h:537 [inline] ip6_finish_output2+0x127d/0x17c0 net/ipv6/ip6_output.c:141 ip6_finish_output+0x41e/0x840 net/ipv6/ip6_output.c:226 NF_HOOK include/linux/netfilter.h:314 [inline] ip6_xmit+0x1108/0x1a20 net/ipv6/ip6_output.c:366 inet6_csk_xmit+0x468/0x710 net/ipv6/inet6_connection_sock.c:135 dccp_transmit_skb+0xf37/0x16d0 net/dccp/output.c:138 dccp_xmit_packet+0x376/0x610 net/dccp/output.c:281 dccp_write_xmit+0x138/0x220 net/dccp/output.c:366 dccp_sendmsg+0x76f/0xb90 net/dccp/proto.c:801 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg+0x1a6/0x270 net/socket.c:733 ____sys_sendmsg+0x53a/0x860 net/socket.c:2573 ___sys_sendmsg net/socket.c:2627 [inline] __sys_sendmmsg+0x36a/0x720 net/socket.c:2716 __do_sys_sendmmsg net/socket.c:2743 [inline] __se_sys_sendmmsg net/socket.c:2740 [inline] __x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2740 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6691: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2353 [inline] slab_free mm/slub.c:4609 [inline] kfree+0x196/0x430 mm/slub.c:4757 skb_kfree_head net/core/skbuff.c:996 [inline] skb_free_head net/core/skbuff.c:1008 [inline] skb_release_data+0x6a0/0x8a0 net/core/skbuff.c:1035 skb_release_all net/core/skbuff.c:1100 [inline] __kfree_skb net/core/skbuff.c:1114 [inline] sk_skb_reason_drop+0x1c9/0x380 net/core/skbuff.c:1152 dccp_v6_do_rcv+0x149/0xb80 sk_backlog_rcv include/net/sock.h:1122 [inline] __release_sock+0x243/0x350 net/core/sock.c:3123 release_sock+0x61/0x1f0 net/core/sock.c:3677 dccp_sendmsg+0x4f0/0xb90 net/dccp/proto.c:803 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg+0x1a6/0x270 net/socket.c:733 ____sys_sendmsg+0x53a/0x860 net/socket.c:2573 ___sys_sendmsg net/socket.c:2627 [inline] __sys_sendmmsg+0x36a/0x720 net/socket.c:2716 __do_sys_sendmmsg net/socket.c:2743 [inline] __se_sys_sendmmsg net/socket.c:2740 [inline] __x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2740 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888065be3000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1186 bytes inside of freed 2048-byte region [ffff888065be3000, ffff888065be3800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x65be0 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801b042000 ffffea0001ee8c00 dead000000000002 raw: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801b042000 ffffea0001ee8c00 dead000000000002 head: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea000196f801 ffffffffffffffff 0000000000000000 head: 0000000700000008 0000000000000000 00000000ffffffff 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 0xd28c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5862, tgid 5862 (syz-executor), ts 65630285730, free_ts 63776353462 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1551 prep_new_page mm/page_alloc.c:1559 [inline] get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3477 __alloc_frozen_pages_noprof+0x292/0x710 mm/page_alloc.c:4739 alloc_pages_mpol+0x311/0x660 mm/mempolicy.c:2270 alloc_slab_page mm/slub.c:2423 [inline] allocate_slab+0x8f/0x3a0 mm/slub.c:2587 new_slab mm/slub.c:2640 [inline] ___slab_alloc+0xc27/0x14a0 mm/slub.c:3826 __slab_alloc+0x58/0xa0 mm/slub.c:3916 __slab_alloc_node mm/slub.c:3991 [inline] slab_alloc_node mm/slub.c:4152 [inline] __do_kmalloc_node mm/slub.c:4293 [inline] __kmalloc_node_track_caller_noprof+0x2e9/0x4c0 mm/slub.c:4313 kmalloc_reserve+0x111/0x2a0 net/core/skbuff.c:537 pskb_expand_head+0x1ee/0x1440 net/core/skbuff.c:2185 netlink_trim+0x1d6/0x2e0 net/netlink/af_netlink.c:1294 netlink_broadcast_filtered+0x76/0x12a0 net/netlink/af_netlink.c:1500 nlmsg_multicast_filtered include/net/netlink.h:1128 [inline] nlmsg_multicast include/net/netlink.h:1147 [inline] nlmsg_notify+0xfb/0x1c0 net/netlink/af_netlink.c:2576 register_netdevice+0x17aa/0x1b60 net/core/dev.c:10992 register_netdev+0x40/0x50 net/core/dev.c:11056 loopback_net_init+0x73/0x150 drivers/net/loopback.c:217 page last free pid 5831 tgid 5831 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1127 [inline] free_unref_folios+0xe40/0x18b0 mm/page_alloc.c:2707 folios_put_refs+0x76c/0x860 mm/swap.c:994 free_pages_and_swap_cache+0x2e5/0x690 mm/swap_state.c:331 __tlb_batch_free_encoded_pages mm/mmu_gather.c:136 [inline] tlb_batch_pages_flush mm/mmu_gather.c:149 [inline] tlb_flush_mmu_free mm/mmu_gather.c:389 [inline] tlb_flush_mmu+0x3a3/0x680 mm/mmu_gather.c:396 tlb_finish_mmu+0xd4/0x200 mm/mmu_gather.c:488 vms_clear_ptes+0x432/0x530 mm/vma.c:1144 vms_complete_munmap_vmas+0x210/0x8f0 mm/vma.c:1186 do_vmi_align_munmap+0x5ef/0x6f0 mm/vma.c:1445 do_vmi_munmap+0x24e/0x2d0 mm/vma.c:1493 __vm_munmap+0x372/0x510 mm/vma.c:2951 __do_sys_munmap mm/mmap.c:1084 [inline] __se_sys_munmap mm/mmap.c:1081 [inline] __x64_sys_munmap+0x60/0x70 mm/mmap.c:1081 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888065be3380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888065be3400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888065be3480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888065be3500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888065be3580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================