netlink: 20 bytes leftover after parsing attributes in process `syz-executor.0'.
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BUG: KASAN: use-after-free in __write_once_size include/linux/compiler.h:226 [inline]
BUG: KASAN: use-after-free in hlist_add_head include/linux/list.h:857 [inline]
BUG: KASAN: use-after-free in qdisc_class_hash_insert+0x25e/0x270 net/sched/sch_api.c:720
Write of size 8 at addr ffff88804b7fc010 by task syz-executor.0/27320

CPU: 1 PID: 27320 Comm: syz-executor.0 Not tainted 5.6.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x188/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd3/0x315 mm/kasan/report.c:374
 __kasan_report.cold+0x1a/0x32 mm/kasan/report.c:506
 kasan_report+0xe/0x20 mm/kasan/common.c:641
 __write_once_size include/linux/compiler.h:226 [inline]
 hlist_add_head include/linux/list.h:857 [inline]
 qdisc_class_hash_insert+0x25e/0x270 net/sched/sch_api.c:720
 qfq_change_class+0x9da/0x1444 net/sched/sch_qfq.c:489
 tc_ctl_tclass+0x52a/0xe60 net/sched/sch_api.c:2101
 rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5436
 netlink_rcv_skb+0x15a/0x410 net/netlink/af_netlink.c:2478
 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
 netlink_unicast+0x537/0x740 net/netlink/af_netlink.c:1329
 netlink_sendmsg+0x882/0xe10 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 ____sys_sendmsg+0x6b9/0x7d0 net/socket.c:2345
 ___sys_sendmsg+0x100/0x170 net/socket.c:2399
 __sys_sendmsg+0xec/0x1b0 net/socket.c:2432
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45c849
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f8198a1ec78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f8198a1f6d4 RCX: 000000000045c849
RDX: 0000000000000000 RSI: 00000000200001c0 RDI: 0000000000000003
RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000009f9 R14: 00000000004ccb11 R15: 000000000076bf0c

Allocated by task 27203:
 save_stack+0x1b/0x80 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc mm/kasan/common.c:515 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:488
 kmem_cache_alloc_trace+0x153/0x7d0 mm/slab.c:3551
 kmalloc include/linux/slab.h:555 [inline]
 kzalloc include/linux/slab.h:669 [inline]
 qfq_change_class+0x756/0x1444 net/sched/sch_qfq.c:464
 tc_ctl_tclass+0x52a/0xe60 net/sched/sch_api.c:2101
 rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5436
 netlink_rcv_skb+0x15a/0x410 net/netlink/af_netlink.c:2478
 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
 netlink_unicast+0x537/0x740 net/netlink/af_netlink.c:1329
 netlink_sendmsg+0x882/0xe10 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 ____sys_sendmsg+0x6b9/0x7d0 net/socket.c:2345
 ___sys_sendmsg+0x100/0x170 net/socket.c:2399
 __sys_sendmsg+0xec/0x1b0 net/socket.c:2432
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 27203:
 save_stack+0x1b/0x80 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 kasan_set_free_info mm/kasan/common.c:337 [inline]
 __kasan_slab_free+0xf7/0x140 mm/kasan/common.c:476
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x109/0x2b0 mm/slab.c:3757
 qfq_change_class+0xeec/0x1444 net/sched/sch_qfq.c:518
 tc_ctl_tclass+0x52a/0xe60 net/sched/sch_api.c:2101
 rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5436
 netlink_rcv_skb+0x15a/0x410 net/netlink/af_netlink.c:2478
 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
 netlink_unicast+0x537/0x740 net/netlink/af_netlink.c:1329
 netlink_sendmsg+0x882/0xe10 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 ____sys_sendmsg+0x6b9/0x7d0 net/socket.c:2345
 ___sys_sendmsg+0x100/0x170 net/socket.c:2399
 __sys_sendmsg+0xec/0x1b0 net/socket.c:2432
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88804b7fc000
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 16 bytes inside of
 128-byte region [ffff88804b7fc000, ffff88804b7fc080)
The buggy address belongs to the page:
page:ffffea00012dff00 refcount:1 mapcount:0 mapping:ffff8880aa000700 index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea0001309208 ffffea00027fa548 ffff8880aa000700
raw: 0000000000000000 ffff88804b7fc000 0000000100000010 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88804b7fbf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88804b7fbf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88804b7fc000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff88804b7fc080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88804b7fc100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fc
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