A use-after-free flaw was found in qdisc_graft in net/sched/sch_api.c in the Linux Kernel due to a race problem leading to a denial-of-service problem. 

Reference:
https://lore.kernel.org/all/20221018203258.2793282-1-edumazet@google.com/


Crash:
    BUG: KASAN: use-after-free in __tcf_qdisc_find.part.0+0xa3a/0xac0 net/sched/cls_api.c:1066
    Read of size 4 at addr ffff88802065e038 by task syz-executor.4/21027
    
    CPU: 0 PID: 21027 Comm: syz-executor.4 Not tainted 6.0.0-rc3-syzkaller-00363-g7726d4c3e60b #0
    Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
    Call Trace:
    <TASK>
    __dump_stack lib/dump_stack.c:88 [inline]
    dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
    print_address_description mm/kasan/report.c:317 [inline]
    print_report.cold+0x2ba/0x719 mm/kasan/report.c:433
    kasan_report+0xb1/0x1e0 mm/kasan/report.c:495
    __tcf_qdisc_find.part.0+0xa3a/0xac0 net/sched/cls_api.c:1066
    __tcf_qdisc_find net/sched/cls_api.c:1051 [inline]
    tc_new_tfilter+0x34f/0x2200 net/sched/cls_api.c:2018
    rtnetlink_rcv_msg+0x955/0xca0 net/core/rtnetlink.c:6081
    netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2501
    netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
    netlink_unicast+0x543/0x7f0 net/netlink/af_netlink.c:1345
    netlink_sendmsg+0x917/0xe10 net/netlink/af_netlink.c:1921
    sock_sendmsg_nosec net/socket.c:714 [inline]
    sock_sendmsg+0xcf/0x120 net/socket.c:734
    ____sys_sendmsg+0x6eb/0x810 net/socket.c:2482
    ___sys_sendmsg+0x110/0x1b0 net/socket.c:2536
    __sys_sendmsg+0xf3/0x1c0 net/socket.c:2565
    do_syscall_x64 arch/x86/entry/common.c:50 [inline]
    do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
    entry_SYSCALL_64_after_hwframe+0x63/0xcd
    RIP: 0033:0x7f5efaa89279