================================================================== BUG: KASAN: slab-use-after-free in mini_qdisc_pair_swap+0x174/0x190 net/sched/sch_generic.c:1618 Write of size 8 at addr ffff88807b9cdac8 by task syz.4.1553/11079 CPU: 1 UID: 0 PID: 11079 Comm: syz.4.1553 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 mini_qdisc_pair_swap+0x174/0x190 net/sched/sch_generic.c:1618 tcf_chain_head_change_item net/sched/cls_api.c:537 [inline] tcf_chain0_head_change net/sched/cls_api.c:551 [inline] tcf_chain_tp_insert net/sched/cls_api.c:1922 [inline] tcf_chain_tp_insert_unique+0x76a/0x970 net/sched/cls_api.c:1971 tc_new_tfilter+0x13d1/0x1810 net/sched/cls_api.c:2405 rtnetlink_rcv_msg+0x802/0xc00 net/core/rtnetlink.c:7132 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800 __sock_sendmsg net/socket.c:815 [inline] ____sys_sendmsg+0x54e/0x850 net/socket.c:2713 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2767 __sys_sendmsg net/socket.c:2799 [inline] __do_sys_sendmsg net/socket.c:2804 [inline] __se_sys_sendmsg net/socket.c:2802 [inline] __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2802 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb7b879e159 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:00007fb7b95da028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fb7b8a26270 RCX: 00007fb7b879e159 RDX: 0000000000000000 RSI: 0000200000001300 RDI: 0000000000000003 RBP: 00007fb7b883503b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fb7b8a26308 R14: 00007fb7b8a26270 R15: 00007ffc9e933848 Allocated by task 9409: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5414 [inline] __kmalloc_node_noprof+0x4b9/0x720 mm/slub.c:5426 _kmalloc_node_noprof include/linux/slab.h:1200 [inline] qdisc_alloc+0x92/0x9d0 net/sched/sch_generic.c:998 qdisc_create+0x12c/0xf00 net/sched/sch_api.c:1293 __tc_modify_qdisc net/sched/sch_api.c:1766 [inline] tc_modify_qdisc+0x18cc/0x2390 net/sched/sch_api.c:1847 rtnetlink_rcv_msg+0x7b9/0xc00 net/core/rtnetlink.c:7141 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800 __sock_sendmsg net/socket.c:815 [inline] ____sys_sendmsg+0x54e/0x850 net/socket.c:2713 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2767 __sys_sendmsg net/socket.c:2799 [inline] __do_sys_sendmsg net/socket.c:2804 [inline] __se_sys_sendmsg net/socket.c:2802 [inline] __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2802 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 15: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2748 [inline] slab_free mm/slub.c:6499 [inline] kfree+0x1c5/0x650 mm/slub.c:6792 rcu_do_batch kernel/rcu/tree.c:2650 [inline] rcu_core+0x926/0x1260 kernel/rcu/tree.c:2919 handle_softirqs+0x226/0x860 kernel/softirq.c:645 run_ksoftirqd+0x36/0x60 kernel/softirq.c:1099 smpboot_thread_fn+0x565/0xa70 kernel/smpboot.c:160 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Last potentially related work creation: kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 __call_rcu_common kernel/rcu/tree.c:3181 [inline] call_rcu+0xee/0x8b0 kernel/rcu/tree.c:3301 qdisc_graft+0xcdd/0x1810 net/sched/sch_api.c:1171 __tc_modify_qdisc net/sched/sch_api.c:1791 [inline] tc_modify_qdisc+0x1968/0x2390 net/sched/sch_api.c:1847 rtnetlink_rcv_msg+0x7b9/0xc00 net/core/rtnetlink.c:7141 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800 __sock_sendmsg net/socket.c:815 [inline] ____sys_sendmsg+0x54e/0x850 net/socket.c:2713 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2767 __sys_sendmsg net/socket.c:2799 [inline] __do_sys_sendmsg net/socket.c:2804 [inline] __se_sys_sendmsg net/socket.c:2802 [inline] __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2802 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88807b9cd800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 712 bytes inside of freed 1024-byte region [ffff88807b9cd800, ffff88807b9cdc00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88807b9cd000 pfn:0x7b9c8 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000240 ffff88801b041dc0 ffffea000080a010 ffffea000080a610 raw: ffff88807b9cd000 000000000010000a 00000000f5000000 0000000000000000 head: 00fff00000000240 ffff88801b041dc0 ffffea000080a010 ffffea000080a610 head: ffff88807b9cd000 000000000010000a 00000000f5000000 0000000000000000 head: 00fff00000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4992, tgid 4992 (udevd), ts 24861537933 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1871 prep_new_page mm/page_alloc.c:1879 [inline] get_page_from_freelist+0x2209/0x2280 mm/page_alloc.c:3943 __alloc_frozen_pages_noprof+0x217/0x5a0 mm/page_alloc.c:5436 alloc_slab_page mm/slub.c:3347 [inline] allocate_slab+0x7d/0x620 mm/slub.c:3462 new_slab mm/slub.c:3513 [inline] refill_objects+0x2d5/0x350 mm/slub.c:7410 refill_sheaf mm/slub.c:2885 [inline] __pcs_replace_empty_main+0x2c8/0x6c0 mm/slub.c:4774 alloc_from_pcs mm/slub.c:4850 [inline] slab_alloc_node mm/slub.c:4984 [inline] __kmalloc_cache_noprof+0x39b/0x600 mm/slub.c:5559 _kmalloc_noprof include/linux/slab.h:991 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] ep_alloc fs/eventpoll.c:1439 [inline] do_epoll_create+0x75/0x440 fs/eventpoll.c:2507 __do_sys_epoll_create1 fs/eventpoll.c:2527 [inline] __se_sys_epoll_create1 fs/eventpoll.c:2525 [inline] __x64_sys_epoll_create1+0x37/0x40 fs/eventpoll.c:2525 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f page last free pid 1 tgid 1 ts 21292978071 stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1418 [inline] free_pages_prepare+0x9eb/0xaf0 mm/page_alloc.c:1463 __free_contig_range_common+0x174/0x340 mm/page_alloc.c:7072 destroy_args+0x4e5/0x570 mm/debug_vm_pgtable.c:993 debug_vm_pgtable+0x3f8/0x410 mm/debug_vm_pgtable.c:1368 do_one_initcall+0x250/0x870 init/main.c:1357 do_initcall_level+0x10a/0x1a0 init/main.c:1419 do_initcalls+0x59/0xa0 init/main.c:1435 kernel_init_freeable+0x29d/0x3e0 init/main.c:1670 kernel_init+0x22/0x1d0 init/main.c:1560 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff88807b9cd980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807b9cda00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88807b9cda80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807b9cdb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807b9cdb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================