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BUG: KASAN: use-after-free in hlist_add_head include/linux/list.h:704 [inline]
BUG: KASAN: use-after-free in qdisc_class_hash_insert+0x25e/0x270 net/sched/sch_api.c:694
Write of size 8 at addr ffff888036c5cf10 by task syz-executor.3/23135

CPU: 1 PID: 23135 Comm: syz-executor.3 Not tainted 4.14.173-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x13e/0x194 lib/dump_stack.c:58
 print_address_description.cold+0x7c/0x1e2 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report mm/kasan/report.c:409 [inline]
 kasan_report.cold+0xa9/0x2ae mm/kasan/report.c:393
 hlist_add_head include/linux/list.h:704 [inline]
 qdisc_class_hash_insert+0x25e/0x270 net/sched/sch_api.c:694
 qfq_change_class+0x88f/0x1081 net/sched/sch_qfq.c:500
 tc_ctl_tclass+0x3e2/0xa00 net/sched/sch_api.c:1848
 rtnetlink_rcv_msg+0x3be/0xb10 net/core/rtnetlink.c:4315
 netlink_rcv_skb+0x127/0x370 net/netlink/af_netlink.c:2433
 netlink_unicast_kernel net/netlink/af_netlink.c:1287 [inline]
 netlink_unicast+0x437/0x620 net/netlink/af_netlink.c:1313
 netlink_sendmsg+0x733/0xbe0 net/netlink/af_netlink.c:1878
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xc5/0x100 net/socket.c:656
 ___sys_sendmsg+0x70a/0x840 net/socket.c:2062
 __sys_sendmsg+0xa3/0x120 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x27/0x40 net/socket.c:2103
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c849
RSP: 002b:00007f58eea9bc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f58eea9c6d4 RCX: 000000000045c849
RDX: 0000000000000000 RSI: 00000000200001c0 RDI: 0000000000000003
RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004
R13: 00000000000009fa R14: 00000000004ccb28 R15: 0000000000000006

Allocated by task 23128:
 save_stack+0x32/0xa0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc mm/kasan/kasan.c:551 [inline]
 kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:529
 kmem_cache_alloc_trace+0x14d/0x7b0 mm/slab.c:3618
 kmalloc include/linux/slab.h:488 [inline]
 kzalloc include/linux/slab.h:661 [inline]
 qfq_change_class+0x64e/0x1081 net/sched/sch_qfq.c:475
 tc_ctl_tclass+0x3e2/0xa00 net/sched/sch_api.c:1848
 rtnetlink_rcv_msg+0x3be/0xb10 net/core/rtnetlink.c:4315
 netlink_rcv_skb+0x127/0x370 net/netlink/af_netlink.c:2433
 netlink_unicast_kernel net/netlink/af_netlink.c:1287 [inline]
 netlink_unicast+0x437/0x620 net/netlink/af_netlink.c:1313
 netlink_sendmsg+0x733/0xbe0 net/netlink/af_netlink.c:1878
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xc5/0x100 net/socket.c:656
 ___sys_sendmsg+0x70a/0x840 net/socket.c:2062
 __sys_sendmsg+0xa3/0x120 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x27/0x40 net/socket.c:2103
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

Freed by task 23128:
 save_stack+0x32/0xa0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xcb/0x260 mm/slab.c:3815
 qfq_change_class+0xd82/0x1081 net/sched/sch_qfq.c:529
 tc_ctl_tclass+0x3e2/0xa00 net/sched/sch_api.c:1848
 rtnetlink_rcv_msg+0x3be/0xb10 net/core/rtnetlink.c:4315
 netlink_rcv_skb+0x127/0x370 net/netlink/af_netlink.c:2433
 netlink_unicast_kernel net/netlink/af_netlink.c:1287 [inline]
 netlink_unicast+0x437/0x620 net/netlink/af_netlink.c:1313
 netlink_sendmsg+0x733/0xbe0 net/netlink/af_netlink.c:1878
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xc5/0x100 net/socket.c:656
 ___sys_sendmsg+0x70a/0x840 net/socket.c:2062
 __sys_sendmsg+0xa3/0x120 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x27/0x40 net/socket.c:2103
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

The buggy address belongs to the object at ffff888036c5cf00
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 16 bytes inside of
 128-byte region [ffff888036c5cf00, ffff888036c5cf80)
The buggy address belongs to the page:
page:ffffea0000db1700 count:1 mapcount:0 mapping:ffff888036c5c000 index:0x0
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffff888036c5c000 0000000000000000 0000000100000015
raw: ffffea0000e567a0 ffffea000235cde0 ffff88812fe56640 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888036c5ce00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff888036c5ce80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff888036c5cf00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff888036c5cf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888036c5d000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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