================================================================== BUG: KASAN: use-after-free in mini_qdisc_pair_swap+0x170/0x190 net/sched/sch_generic.c:1571 Write of size 8 at addr ffff8880316e2308 by task syz.0.744/7281 CPU: 0 PID: 7281 Comm: syz.0.744 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 print_address_description mm/kasan/report.c:316 [inline] print_report+0xa8/0x210 mm/kasan/report.c:420 kasan_report+0x10b/0x140 mm/kasan/report.c:524 mini_qdisc_pair_swap+0x170/0x190 net/sched/sch_generic.c:1571 tcf_chain_head_change_item net/sched/cls_api.c:388 [inline] tcf_chain0_head_change net/sched/cls_api.c:402 [inline] tcf_chain_tp_insert net/sched/cls_api.c:1680 [inline] tcf_chain_tp_insert_unique+0x9d3/0xb90 net/sched/cls_api.c:1729 tc_new_tfilter+0x14f4/0x1970 net/sched/cls_api.c:2156 rtnetlink_rcv_msg+0x8b2/0xfb0 net/core/rtnetlink.c:6157 netlink_rcv_skb+0x1ef/0x440 net/netlink/af_netlink.c:2516 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x7ad/0x920 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x8ad/0xbd0 net/netlink/af_netlink.c:1877 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:730 [inline] ____sys_sendmsg+0x5ed/0x9a0 net/socket.c:2519 ___sys_sendmsg+0x2a2/0x360 net/socket.c:2573 __sys_sendmsg net/socket.c:2602 [inline] __do_sys_sendmsg net/socket.c:2611 [inline] __se_sys_sendmsg+0x1c3/0x2b0 net/socket.c:2609 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7ff01b99e559 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ff019bd5028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007ff01bc26090 RCX: 00007ff01b99e559 RDX: 0000000000000000 RSI: 0000200000001300 RDI: 0000000000000003 RBP: 00007ff01ba358b0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff01bc26128 R14: 00007ff01bc26090 R15: 00007ffca3902128 Allocated by task 7216: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 ____kasan_kmalloc mm/kasan/common.c:375 [inline] __kasan_kmalloc+0x8e/0xa0 mm/kasan/common.c:384 kasan_kmalloc include/linux/kasan.h:211 [inline] __do_kmalloc_node mm/slab_common.c:936 [inline] __kmalloc_node+0xb2/0x240 mm/slab_common.c:943 kmalloc_node include/linux/slab.h:589 [inline] kzalloc_node include/linux/slab.h:710 [inline] qdisc_alloc+0x8f/0xa40 net/sched/sch_generic.c:951 qdisc_create+0x16e/0x10c0 net/sched/sch_api.c:1284 tc_modify_qdisc+0xb43/0x1de0 net/sched/sch_api.c:-1 rtnetlink_rcv_msg+0x863/0xfb0 net/core/rtnetlink.c:6166 netlink_rcv_skb+0x1ef/0x440 net/netlink/af_netlink.c:2516 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x7ad/0x920 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x8ad/0xbd0 net/netlink/af_netlink.c:1877 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:730 [inline] ____sys_sendmsg+0x5ed/0x9a0 net/socket.c:2519 ___sys_sendmsg+0x2a2/0x360 net/socket.c:2573 __sys_sendmsg net/socket.c:2602 [inline] __do_sys_sendmsg net/socket.c:2611 [inline] __se_sys_sendmsg+0x1c3/0x2b0 net/socket.c:2609 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Freed by task 7269: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x27/0x40 mm/kasan/generic.c:516 ____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1729 [inline] slab_free_freelist_hook+0x133/0x1b0 mm/slub.c:1755 slab_free mm/slub.c:3687 [inline] __kmem_cache_free+0xb6/0x200 mm/slub.c:3700 rcu_do_batch kernel/rcu/tree.c:2297 [inline] rcu_core+0x9a3/0x1740 kernel/rcu/tree.c:2557 handle_softirqs+0x291/0x910 kernel/softirq.c:596 __do_softirq kernel/softirq.c:630 [inline] invoke_softirq kernel/softirq.c:470 [inline] __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 Last potentially related work creation: kasan_save_stack+0x3a/0x60 mm/kasan/common.c:46 __kasan_record_aux_stack+0xb2/0xc0 mm/kasan/generic.c:486 call_rcu+0x14f/0x950 kernel/rcu/tree.c:2849 qdisc_graft+0xbba/0x17c0 net/sched/sch_api.c:1134 tc_modify_qdisc+0xe91/0x1de0 net/sched/sch_api.c:1787 rtnetlink_rcv_msg+0x863/0xfb0 net/core/rtnetlink.c:6166 netlink_rcv_skb+0x1ef/0x440 net/netlink/af_netlink.c:2516 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x7ad/0x920 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x8ad/0xbd0 net/netlink/af_netlink.c:1877 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:730 [inline] ____sys_sendmsg+0x5ed/0x9a0 net/socket.c:2519 ___sys_sendmsg+0x2a2/0x360 net/socket.c:2573 __sys_sendmsg net/socket.c:2602 [inline] __do_sys_sendmsg net/socket.c:2611 [inline] __se_sys_sendmsg+0x1c3/0x2b0 net/socket.c:2609 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 The buggy address belongs to the object at ffff8880316e2000 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 776 bytes inside of 1024-byte region [ffff8880316e2000, ffff8880316e2400) The buggy address belongs to the physical page: page:ffffea0000c5b800 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x316e0 head:ffffea0000c5b800 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 dead000000000100 dead000000000122 ffff888018441dc0 raw: 0000000000000000 0000000000100010 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 0x52a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 1, tgid 1 (swapper/0), ts 19983237092, free_ts 0 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2560 prep_new_page mm/page_alloc.c:2567 [inline] get_page_from_freelist+0x206b/0x2180 mm/page_alloc.c:4358 __alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5658 alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2115 alloc_slab_page+0x5d/0x180 mm/slub.c:1799 allocate_slab mm/slub.c:1944 [inline] new_slab+0x87/0x2d0 mm/slub.c:1997 ___slab_alloc+0xbc5/0x1240 mm/slub.c:3154 __slab_alloc mm/slub.c:3240 [inline] slab_alloc_node mm/slub.c:3325 [inline] __kmem_cache_alloc_node+0x126/0x270 mm/slub.c:3398 kmalloc_trace+0x26/0xe0 mm/slab_common.c:1026 kmalloc include/linux/slab.h:563 [inline] kzalloc include/linux/slab.h:699 [inline] batadv_hardif_add_interface net/batman-adv/hard-interface.c:876 [inline] batadv_hard_if_event+0xd53/0x1510 net/batman-adv/hard-interface.c:964 call_netdevice_notifier net/core/dev.c:1714 [inline] call_netdevice_register_notifiers net/core/dev.c:1722 [inline] call_netdevice_register_net_notifiers+0x10a/0x440 net/core/dev.c:1752 register_netdevice_notifier+0x108/0x410 net/core/dev.c:1803 batadv_init+0x180/0x1ad net/batman-adv/main.c:115 do_one_initcall+0x257/0x800 init/main.c:1271 do_initcall_level+0x13d/0x1ed init/main.c:1344 do_initcalls+0x4b/0x8a init/main.c:1360 page_owner free stack trace missing Memory state around the buggy address: ffff8880316e2200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880316e2280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880316e2300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880316e2380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880316e2400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================