================================================================== BUG: KASAN: slab-use-after-free in qfq_reset_qdisc+0x323/0x420 net/sched/sch_qfq.c:1484 Read of size 8 at addr ffff888054fa1a50 by task syz.2.202/6737 CPU: 1 UID: 0 PID: 6737 Comm: syz.2.202 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 qfq_reset_qdisc+0x323/0x420 net/sched/sch_qfq.c:1484 qdisc_reset+0xe0/0x660 net/sched/sch_generic.c:1038 __qdisc_destroy+0xd3/0x4d0 net/sched/sch_generic.c:1077 qdisc_put+0xab/0xe0 net/sched/sch_generic.c:1109 dev_shutdown+0x1d0/0x430 net/sched/sch_generic.c:1497 unregister_netdevice_many_notify+0xb12/0x25c0 net/core/dev.c:12272 unregister_netdevice_many net/core/dev.c:12347 [inline] unregister_netdevice_queue+0x305/0x3f0 net/core/dev.c:12161 unregister_netdevice include/linux/netdevice.h:3389 [inline] __tun_detach+0x119c/0x1490 drivers/net/tun.c:621 tun_detach drivers/net/tun.c:637 [inline] tun_chr_close+0xc2/0x230 drivers/net/tun.c:3436 __fput+0x402/0xb70 fs/file_table.c:468 task_work_run+0x150/0x240 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xec/0x130 kernel/entry/common.c:43 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x426/0xfa0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f760718efc9 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:00007ffe250d8e88 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007f76073e7da0 RCX: 00007f760718efc9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f76073e7da0 R08: 0000000000000000 R09: 0000000c250d917f R10: 000000000003fd80 R11: 0000000000000246 R12: 000000000001cc9c R13: 00007ffe250d8f80 R14: ffffffffffffffff R15: 00007ffe250d8fa0 Allocated by task 6738: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:400 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:417 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] qfq_change_class+0x2ba/0x1ec0 net/sched/sch_qfq.c:479 __tc_ctl_tclass net/sched/sch_api.c:2274 [inline] tc_ctl_tclass+0x59d/0x16c0 net/sched/sch_api.c:2304 rtnetlink_rcv_msg+0x3c9/0xe90 net/core/rtnetlink.c:6963 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2552 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xa98/0xc70 net/socket.c:2630 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2684 __sys_sendmsg+0x16d/0x220 net/socket.c:2716 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6738: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 __kasan_save_free_info+0x3b/0x60 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+0x5f/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2530 [inline] slab_free mm/slub.c:6619 [inline] kfree+0x2b8/0x6d0 mm/slub.c:6826 qfq_change_class+0x1577/0x1ec0 net/sched/sch_qfq.c:533 __tc_ctl_tclass net/sched/sch_api.c:2274 [inline] tc_ctl_tclass+0x59d/0x16c0 net/sched/sch_api.c:2304 rtnetlink_rcv_msg+0x3c9/0xe90 net/core/rtnetlink.c:6963 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2552 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xa98/0xc70 net/socket.c:2630 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2684 __sys_sendmsg+0x16d/0x220 net/socket.c:2716 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888054fa1a00 which belongs to the cache kmalloc-128 of size 128 The buggy address is located 80 bytes inside of freed 128-byte region [ffff888054fa1a00, ffff888054fa1a80) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x54fa1 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88813ffa6a00 dead000000000122 0000000000000000 raw: 0000000000000000 0000000080100010 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 0x52c00(GFP_NOIO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5939, tgid 5939 (kworker/0:5), ts 117058764342, free_ts 117058111295 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1850 prep_new_page mm/page_alloc.c:1858 [inline] get_page_from_freelist+0x10a3/0x3a30 mm/page_alloc.c:3884 __alloc_frozen_pages_noprof+0x25f/0x2470 mm/page_alloc.c:5183 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:3046 [inline] allocate_slab mm/slub.c:3219 [inline] new_slab+0x24a/0x360 mm/slub.c:3273 ___slab_alloc+0xdc4/0x1ae0 mm/slub.c:4643 __slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4762 __slab_alloc_node mm/slub.c:4838 [inline] slab_alloc_node mm/slub.c:5260 [inline] __kmalloc_cache_noprof+0x477/0x780 mm/slub.c:5750 kmalloc_noprof include/linux/slab.h:957 [inline] dummy_urb_enqueue+0xa3/0x920 drivers/usb/gadget/udc/dummy_hcd.c:1273 usb_hcd_submit_urb+0x25b/0x1c60 drivers/usb/core/hcd.c:1546 usb_submit_urb+0x89f/0x1990 drivers/usb/core/urb.c:587 usb_start_wait_urb+0x104/0x4b0 drivers/usb/core/message.c:59 usb_internal_control_msg drivers/usb/core/message.c:103 [inline] usb_control_msg+0x326/0x4a0 drivers/usb/core/message.c:154 usb_get_string+0xab/0x1a0 drivers/usb/core/message.c:844 usb_string_sub+0x107/0x390 drivers/usb/core/message.c:883 usb_string+0x307/0x670 drivers/usb/core/message.c:988 page last free pid 5812 tgid 5812 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1394 [inline] __free_frozen_pages+0x7df/0x1160 mm/page_alloc.c:2906 vfree+0x1fd/0xb50 mm/vmalloc.c:3440 copy_entries_to_user net/ipv4/netfilter/ip_tables.c:866 [inline] get_entries net/ipv4/netfilter/ip_tables.c:1022 [inline] do_ipt_get_ctl+0x8ae/0xaa0 net/ipv4/netfilter/ip_tables.c:1668 nf_getsockopt+0x7c/0xe0 net/netfilter/nf_sockopt.c:116 ip_getsockopt+0x18c/0x1e0 net/ipv4/ip_sockglue.c:1777 tcp_getsockopt+0xa1/0x100 net/ipv4/tcp.c:4810 do_sock_getsockopt+0x34d/0x440 net/socket.c:2421 __sys_getsockopt+0x12f/0x260 net/socket.c:2450 __do_sys_getsockopt net/socket.c:2457 [inline] __se_sys_getsockopt net/socket.c:2454 [inline] __x64_sys_getsockopt+0xbd/0x160 net/socket.c:2454 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888054fa1900: 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc ffff888054fa1980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888054fa1a00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888054fa1a80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888054fa1b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc ==================================================================