syzbot

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BUG: KASAN: use-after-free in __hlist_del include/linux/list.h:884 [inline]
BUG: KASAN: use-after-free in hlist_del_init_rcu include/linux/rculist.h:184 [inline]
BUG: KASAN: use-after-free in br_multicast_rport_del net/bridge/br_multicast.c:1476 [inline]
BUG: KASAN: use-after-free in br_ip4_multicast_rport_del net/bridge/br_multicast.c:1482 [inline]
BUG: KASAN: use-after-free in br_multicast_set_port_router+0x278/0x9e0 net/bridge/br_multicast.c:4380
Write of size 8 at addr ffff0000f599ba68 by task syz.0.1134/8238

CPU: 1 PID: 8238 Comm: syz.0.1134 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025
Call trace:
 dump_backtrace+0x1c0/0x1ec 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+0xf4/0x15c 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+0xa8/0xfc mm/kasan/report.c:524
 __asan_report_store8_noabort+0x2c/0x38 mm/kasan/report_generic.c:356
 __hlist_del include/linux/list.h:884 [inline]
 hlist_del_init_rcu include/linux/rculist.h:184 [inline]
 br_multicast_rport_del net/bridge/br_multicast.c:1476 [inline]
 br_ip4_multicast_rport_del net/bridge/br_multicast.c:1482 [inline]
 br_multicast_set_port_router+0x278/0x9e0 net/bridge/br_multicast.c:4380
 br_setport+0xa20/0xf54 net/bridge/br_netlink.c:986
 br_port_slave_changelink+0x138/0x160 net/bridge/br_netlink.c:1159
 __rtnl_newlink net/core/rtnetlink.c:3601 [inline]
 rtnl_newlink+0x10b8/0x1a50 net/core/rtnetlink.c:3655
 rtnetlink_rcv_msg+0x698/0xcdc net/core/rtnetlink.c:6150
 netlink_rcv_skb+0x218/0x3e8 net/netlink/af_netlink.c:2511
 rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:6168
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x60c/0x814 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x6f4/0x9c0 net/netlink/af_netlink.c:1872
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x5c8/0x938 net/socket.c:2518
 ___sys_sendmsg net/socket.c:2572 [inline]
 __sys_sendmsg+0x288/0x374 net/socket.c:2601
 __do_sys_sendmsg net/socket.c:2610 [inline]
 __se_sys_sendmsg net/socket.c:2608 [inline]
 __arm64_sys_sendmsg+0x80/0x94 net/socket.c:2608
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 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 8209:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4c/0x80 mm/kasan/common.c:53
 kasan_save_alloc_info+0x24/0x30 mm/kasan/generic.c:505
 ____kasan_kmalloc mm/kasan/common.c:375 [inline]
 __kasan_kmalloc+0xa0/0xb8 mm/kasan/common.c:384
 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+0x264/0x714 net/core/skbuff.c:515
 alloc_skb_fclone include/linux/skbuff.h:1321 [inline]
 tipc_buf_acquire net/tipc/msg.c:72 [inline]
 tipc_msg_build+0xc0/0xb9c net/tipc/msg.c:390
 tipc_send_group_bcast+0x814/0xacc net/tipc/socket.c:1128
 __tipc_sendmsg+0x2ac/0x28b8 net/tipc/socket.c:1436
 tipc_sendmsg+0x60/0x1bc net/tipc/socket.c:1403
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x5c8/0x938 net/socket.c:2518
 ___sys_sendmsg net/socket.c:2572 [inline]
 __sys_sendmmsg+0x344/0x834 net/socket.c:2658
 __do_sys_sendmmsg net/socket.c:2687 [inline]
 __se_sys_sendmmsg net/socket.c:2684 [inline]
 __arm64_sys_sendmmsg+0xa0/0xbc net/socket.c:2684
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 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

Freed by task 8209:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4c/0x80 mm/kasan/common.c:53
 kasan_save_free_info+0x38/0x5c mm/kasan/generic.c:516
 ____kasan_slab_free+0x148/0x1b0 mm/kasan/common.c:237
 __kasan_slab_free+0x18/0x28 mm/kasan/common.c:245
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1729 [inline]
 slab_free_freelist_hook+0x16c/0x1e8 mm/slub.c:1755
 slab_free mm/slub.c:3687 [inline]
 __kmem_cache_free+0xbc/0x218 mm/slub.c:3700
 kfree+0xd0/0x1a8 mm/slab_common.c:988
 skb_free_head net/core/skbuff.c:762 [inline]
 skb_release_data+0x434/0x63c 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+0x198/0x418 net/core/skbuff.c:893
 kfree_skb include/linux/skbuff.h:1220 [inline]
 __skb_queue_purge include/linux/skbuff.h:3183 [inline]
 tipc_mcast_xmit+0xe84/0x1324 net/tipc/bcast.c:428
 tipc_send_group_bcast+0x840/0xacc net/tipc/socket.c:1133
 __tipc_sendmsg+0x2ac/0x28b8 net/tipc/socket.c:1436
 tipc_sendmsg+0x60/0x1bc net/tipc/socket.c:1403
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x5c8/0x938 net/socket.c:2518
 ___sys_sendmsg net/socket.c:2572 [inline]
 __sys_sendmmsg+0x344/0x834 net/socket.c:2658
 __do_sys_sendmmsg net/socket.c:2687 [inline]
 __se_sys_sendmmsg net/socket.c:2684 [inline]
 __arm64_sys_sendmmsg+0xa0/0xbc net/socket.c:2684
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 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:46
 __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+0x100/0x94c kernel/rcu/tree.c:2849
 del_nbp+0x814/0x904 net/bridge/br_if.c:376
 br_del_if+0x154/0x320 net/bridge/br_if.c:740
 br_del_slave+0x28/0x38 net/bridge/br_device.c:395
 do_set_master net/core/rtnetlink.c:2616 [inline]
 do_setlink+0xc28/0x3434 net/core/rtnetlink.c:2840
 __rtnl_newlink net/core/rtnetlink.c:3608 [inline]
 rtnl_newlink+0x13cc/0x1a50 net/core/rtnetlink.c:3655
 rtnetlink_rcv_msg+0x698/0xcdc net/core/rtnetlink.c:6150
 netlink_rcv_skb+0x218/0x3e8 net/netlink/af_netlink.c:2511
 rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:6168
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x60c/0x814 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x6f4/0x9c0 net/netlink/af_netlink.c:1872
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x5c8/0x938 net/socket.c:2518
 ___sys_sendmsg net/socket.c:2572 [inline]
 __sys_sendmsg+0x288/0x374 net/socket.c:2601
 __do_sys_sendmsg net/socket.c:2610 [inline]
 __se_sys_sendmsg net/socket.c:2608 [inline]
 __arm64_sys_sendmsg+0x80/0x94 net/socket.c:2608
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 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

Second to last potentially related work creation:
 kasan_save_stack+0x40/0x70 mm/kasan/common.c:46
 __kasan_record_aux_stack+0xc0/0xdc mm/kasan/generic.c:486
 kasan_record_aux_stack_noalloc+0x14/0x20 mm/kasan/generic.c:496
 kvfree_call_rcu+0xb4/0x6e8 kernel/rcu/tree.c:3405
 neigh_destroy+0x458/0x650 net/core/neighbour.c:923
 neigh_release include/net/neighbour.h:448 [inline]
 neigh_cleanup_and_release+0x154/0x3b4 net/core/neighbour.c:104
 neigh_del net/core/neighbour.c:226 [inline]
 neigh_remove_one+0x318/0x420 net/core/neighbour.c:247
 neigh_forced_gc net/core/neighbour.c:280 [inline]
 neigh_alloc net/core/neighbour.c:486 [inline]
 ___neigh_create+0x450/0x2400 net/core/neighbour.c:649
 __neigh_create+0x44/0x58 net/core/neighbour.c:738
 ip6_finish_output2+0x1678/0x1840 net/ipv6/ip6_output.c:129
 __ip6_finish_output net/ipv6/ip6_output.c:205 [inline]
 ip6_finish_output+0x594/0x92c net/ipv6/ip6_output.c:216
 NF_HOOK_COND include/linux/netfilter.h:291 [inline]
 ip6_output+0x274/0x500 net/ipv6/ip6_output.c:237
 dst_output include/net/dst.h:453 [inline]
 NF_HOOK include/linux/netfilter.h:302 [inline]
 ndisc_send_skb+0xc30/0x164c net/ipv6/ndisc.c:513
 ndisc_send_ns net/ipv6/ndisc.c:671 [inline]
 ndisc_solicit+0x29c/0x52c net/ipv6/ndisc.c:763
 neigh_probe+0xc4/0x124 net/core/neighbour.c:1080
 __neigh_event_send+0xd00/0x1490 net/core/neighbour.c:1247
 neigh_event_send_probe include/net/neighbour.h:469 [inline]
 neigh_event_send include/net/neighbour.h:475 [inline]
 neigh_resolve_output+0x180/0x650 net/core/neighbour.c:1552
 neigh_output include/net/neighbour.h:545 [inline]
 ip6_finish_output2+0xd5c/0x1840 net/ipv6/ip6_output.c:138
 __ip6_finish_output net/ipv6/ip6_output.c:205 [inline]
 ip6_finish_output+0x594/0x92c net/ipv6/ip6_output.c:216
 NF_HOOK_COND include/linux/netfilter.h:291 [inline]
 ip6_output+0x274/0x500 net/ipv6/ip6_output.c:237
 dst_output include/net/dst.h:453 [inline]
 NF_HOOK include/linux/netfilter.h:302 [inline]
 ip6_xmit+0x1164/0x1a24 net/ipv6/ip6_output.c:357
 tcp_v6_send_synack+0x624/0xb54 net/ipv6/tcp_ipv6.c:567
 tcp_conn_request+0x18b8/0x25d4 net/ipv4/tcp_input.c:7147
 tcp_v6_conn_request+0x264/0x37c net/ipv6/tcp_ipv6.c:1177
 tcp_rcv_state_process+0x121c/0x3854 net/ipv4/tcp_input.c:6583
 tcp_v6_do_rcv+0x868/0x1128 net/ipv6/tcp_ipv6.c:1510
 tcp_v6_rcv+0x19cc/0x2000 net/ipv6/tcp_ipv6.c:1739
 ip6_protocol_deliver_rcu+0x928/0x11cc net/ipv6/ip6_input.c:438
 ip6_input_finish+0x164/0x294 net/ipv6/ip6_input.c:483
 NF_HOOK+0x2dc/0x36c 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+0x2dc/0x36c 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/0x2a8 net/core/dev.c:5695
 netif_receive_skb_internal net/core/dev.c:5781 [inline]
 netif_receive_skb+0x1e8/0x924 net/core/dev.c:5840
 tun_rx_batched+0x48c/0x5dc drivers/net/tun.c:-1
 tun_get_user+0x1fe8/0x3298 drivers/net/tun.c:1998
 tun_chr_write_iter+0xfc/0x200 drivers/net/tun.c:2044
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x3ec/0x7f0 fs/read_write.c:584
 ksys_write+0x12c/0x224 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __arm64_sys_write+0x7c/0x90 fs/read_write.c:646
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 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

The buggy address belongs to the object at ffff0000f599b800
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 616 bytes inside of
 1024-byte region [ffff0000f599b800, ffff0000f599bc00)

The buggy address belongs to the physical page:
page:00000000535a3200 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x135998
head:00000000535a3200 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000010200 fffffc0003309c00 dead000000000002 ffff0000c0002780
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000f599b900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff0000f599b980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff0000f599ba00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                          ^
 ffff0000f599ba80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff0000f599bb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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