================================================================== BUG: KASAN: slab-use-after-free in qfq_reset_qdisc+0xf9/0x240 net/sched/sch_qfq.c:1484 Read of size 8 at addr ffff8880563ef750 by task syz.0.894/9245 CPU: 1 UID: 0 PID: 9245 Comm: syz.0.894 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x240 mm/kasan/report.c:482 kasan_report+0x118/0x150 mm/kasan/report.c:595 qfq_reset_qdisc+0xf9/0x240 net/sched/sch_qfq.c:1484 qdisc_reset+0xff/0x560 net/sched/sch_generic.c:1034 __qdisc_destroy+0x120/0x400 net/sched/sch_generic.c:1073 notify_and_destroy net/sched/sch_api.c:1062 [inline] qdisc_graft+0x111f/0x1590 net/sched/sch_api.c:1159 __tc_modify_qdisc net/sched/sch_api.c:1761 [inline] tc_modify_qdisc+0x16d3/0x2020 net/sched/sch_api.c:1817 rtnetlink_rcv_msg+0x77c/0xb70 net/core/rtnetlink.c:6967 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:733 ____sys_sendmsg+0x505/0x820 net/socket.c:2608 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2662 __sys_sendmsg net/socket.c:2694 [inline] __do_sys_sendmsg net/socket.c:2699 [inline] __se_sys_sendmsg net/socket.c:2697 [inline] __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2697 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff69c18f749 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:00007ff69cf59038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007ff69c3e5fa0 RCX: 00007ff69c18f749 RDX: 0000000020008850 RSI: 00002000000012c0 RDI: 0000000000000004 RBP: 00007ff69c213f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff69c3e6038 R14: 00007ff69c3e5fa0 R15: 00007fff6534eac8 Allocated by task 8915: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:400 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417 kasan_kmalloc include/linux/kasan.h:262 [inline] __kmalloc_cache_noprof+0x3d5/0x6f0 mm/slub.c:5771 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] qfq_change_class+0x5c4/0xea0 net/sched/sch_qfq.c:479 __tc_ctl_tclass net/sched/sch_api.c:2279 [inline] tc_ctl_tclass+0xaa0/0x1500 net/sched/sch_api.c:2309 rtnetlink_rcv_msg+0x77c/0xb70 net/core/rtnetlink.c:6967 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:733 ____sys_sendmsg+0x505/0x820 net/socket.c:2608 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2662 __sys_sendmsg net/socket.c:2694 [inline] __do_sys_sendmsg net/socket.c:2699 [inline] __se_sys_sendmsg net/socket.c:2697 [inline] __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2697 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 9106: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 __kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587 kasan_save_free_info mm/kasan/kasan.h:406 [inline] poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free mm/slub.c:6663 [inline] kfree+0x1c0/0x660 mm/slub.c:6871 qfq_change_class+0xb0c/0xea0 net/sched/sch_qfq.c:533 __tc_ctl_tclass net/sched/sch_api.c:2279 [inline] tc_ctl_tclass+0xaa0/0x1500 net/sched/sch_api.c:2309 rtnetlink_rcv_msg+0x77c/0xb70 net/core/rtnetlink.c:6967 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:733 ____sys_sendmsg+0x505/0x820 net/socket.c:2608 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2662 __sys_sendmsg net/socket.c:2694 [inline] __do_sys_sendmsg net/socket.c:2699 [inline] __se_sys_sendmsg net/socket.c:2697 [inline] __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2697 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff8880563ef700 which belongs to the cache kmalloc-128 of size 128 The buggy address is located 80 bytes inside of freed 128-byte region [ffff8880563ef700, ffff8880563ef780) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x563ef anon flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88801a026a00 0000000000000000 dead000000000001 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x252800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_THISNODE), pid 7533, tgid 7530 (syz.4.428), ts 134009789394, free_ts 128825570112 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x234/0x290 mm/page_alloc.c:1845 prep_new_page mm/page_alloc.c:1853 [inline] get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3879 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5183 alloc_slab_page mm/slub.c:3077 [inline] allocate_slab+0x7a/0x3b0 mm/slub.c:3248 new_slab mm/slub.c:3302 [inline] ___slab_alloc+0xf2b/0x1960 mm/slub.c:4651 __slab_alloc+0x65/0x100 mm/slub.c:4774 __slab_alloc_node mm/slub.c:4850 [inline] slab_alloc_node mm/slub.c:5246 [inline] __do_kmalloc_node mm/slub.c:5651 [inline] __kmalloc_node_noprof+0x5d0/0x810 mm/slub.c:5658 kmalloc_array_node_noprof include/linux/slab.h:1075 [inline] alloc_slab_obj_exts+0x3e/0x100 mm/slub.c:2123 account_slab mm/slub.c:3202 [inline] allocate_slab+0x1cc/0x3b0 mm/slub.c:3267 new_slab mm/slub.c:3302 [inline] ___slab_alloc+0xf2b/0x1960 mm/slub.c:4651 __slab_alloc+0x65/0x100 mm/slub.c:4774 __slab_alloc_node mm/slub.c:4850 [inline] slab_alloc_node mm/slub.c:5246 [inline] __kmalloc_cache_noprof+0x411/0x6f0 mm/slub.c:5766 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] push_stack+0x80/0x3a0 kernel/bpf/verifier.c:2121 check_cond_jmp_op+0x1840/0x2e20 kernel/bpf/verifier.c:16999 do_check_insn kernel/bpf/verifier.c:20441 [inline] do_check+0x58f5/0xeba0 kernel/bpf/verifier.c:20581 do_check_common+0x19cc/0x25b0 kernel/bpf/verifier.c:23865 page last free pid 7316 tgid 7315 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1394 [inline] __free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2901 discard_slab mm/slub.c:3346 [inline] __put_partials+0x146/0x170 mm/slub.c:3886 put_cpu_partial+0x1f2/0x2d0 mm/slub.c:3961 __slab_free+0x288/0x2a0 mm/slub.c:5947 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:352 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4948 [inline] slab_alloc_node mm/slub.c:5258 [inline] __kmalloc_cache_noprof+0x36f/0x6f0 mm/slub.c:5766 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] bpf_int_jit_compile+0x1e8/0x14b0 arch/x86/net/bpf_jit_comp.c:3716 bpf_prog_select_runtime+0x4a3/0x820 kernel/bpf/core.c:2526 bpf_prog_load+0x13e9/0x1a10 kernel/bpf/syscall.c:3092 __sys_bpf+0x507/0x860 kernel/bpf/syscall.c:6164 __do_sys_bpf kernel/bpf/syscall.c:6274 [inline] __se_sys_bpf kernel/bpf/syscall.c:6272 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6272 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff8880563ef600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880563ef680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880563ef700: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880563ef780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880563ef800: 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc ==================================================================