syzbot

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000007
R13: 00000000000f4240 R14: 0000000000000000 R15: 0000000000000000
netlink: 24 bytes leftover after parsing attributes in process `syz-executor409'.
netlink: 72 bytes leftover after parsing attributes in process `syz-executor409'.
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BUG: KASAN: use-after-free in qdisc_class_find include/net/sch_generic.h:528 [inline]
BUG: KASAN: use-after-free in qfq_find_class+0x162/0x190 net/sched/sch_qfq.c:214
Read of size 4 at addr ffff88809bbde480 by task syz-executor409/8308

CPU: 1 PID: 8308 Comm: syz-executor409 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256
 kasan_report_error.cold+0x8a/0x1b9 mm/kasan/report.c:354
 kasan_report mm/kasan/report.c:412 [inline]
 __asan_report_load4_noabort+0x88/0x90 mm/kasan/report.c:432
 qdisc_class_find include/net/sch_generic.h:528 [inline]
 qfq_find_class+0x162/0x190 net/sched/sch_qfq.c:214
 tc_ctl_tclass+0x765/0xcd0 net/sched/sch_api.c:1957
 rtnetlink_rcv_msg+0x453/0xb80 net/core/rtnetlink.c:4782
 netlink_rcv_skb+0x160/0x440 net/netlink/af_netlink.c:2463
 netlink_unicast_kernel net/netlink/af_netlink.c:1325 [inline]
 netlink_unicast+0x4d5/0x690 net/netlink/af_netlink.c:1351
 netlink_sendmsg+0x6c3/0xc50 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg+0xc3/0x120 net/socket.c:661
 ___sys_sendmsg+0x7bb/0x8e0 net/socket.c:2227
 __sys_sendmsg net/socket.c:2265 [inline]
 __do_sys_sendmsg net/socket.c:2274 [inline]
 __se_sys_sendmsg net/socket.c:2272 [inline]
 __x64_sys_sendmsg+0x132/0x220 net/socket.c:2272
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fc456b90e69
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 15 00 00 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff2b505fe8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fff2b506020 RCX: 00007fc456b90e69
RDX: 0000000000000000 RSI: 00000000200001c0 RDI: 0000000000000005
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000246 R12: 00007fff2b506010
R13: 00000000000f4240 R14: 00000000000084d1 R15: 00007fff2b505ff4

Allocated by task 8303:
 kmem_cache_alloc_trace+0x12f/0x380 mm/slab.c:3625
 kmalloc include/linux/slab.h:515 [inline]
 kzalloc include/linux/slab.h:709 [inline]
 qfq_change_class+0x885/0x16f0 net/sched/sch_qfq.c:476
 tc_ctl_tclass+0x501/0xcd0 net/sched/sch_api.c:1993
 rtnetlink_rcv_msg+0x453/0xb80 net/core/rtnetlink.c:4782
 netlink_rcv_skb+0x160/0x440 net/netlink/af_netlink.c:2463
 netlink_unicast_kernel net/netlink/af_netlink.c:1325 [inline]
 netlink_unicast+0x4d5/0x690 net/netlink/af_netlink.c:1351
 netlink_sendmsg+0x6c3/0xc50 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg+0xc3/0x120 net/socket.c:661
 ___sys_sendmsg+0x7bb/0x8e0 net/socket.c:2227
 __sys_sendmsg net/socket.c:2265 [inline]
 __do_sys_sendmsg net/socket.c:2274 [inline]
 __se_sys_sendmsg net/socket.c:2272 [inline]
 __x64_sys_sendmsg+0x132/0x220 net/socket.c:2272
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 8303:
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xcc/0x210 mm/slab.c:3822
 qfq_change_class+0x11ff/0x16f0 net/sched/sch_qfq.c:528
 tc_ctl_tclass+0x501/0xcd0 net/sched/sch_api.c:1993
 rtnetlink_rcv_msg+0x453/0xb80 net/core/rtnetlink.c:4782
 netlink_rcv_skb+0x160/0x440 net/netlink/af_netlink.c:2463
 netlink_unicast_kernel net/netlink/af_netlink.c:1325 [inline]
 netlink_unicast+0x4d5/0x690 net/netlink/af_netlink.c:1351
 netlink_sendmsg+0x6c3/0xc50 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg+0xc3/0x120 net/socket.c:661
 ___sys_sendmsg+0x7bb/0x8e0 net/socket.c:2227
 __sys_sendmsg net/socket.c:2265 [inline]
 __do_sys_sendmsg net/socket.c:2274 [inline]
 __se_sys_sendmsg net/socket.c:2272 [inline]
 __x64_sys_sendmsg+0x132/0x220 net/socket.c:2272
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88809bbde480
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 0 bytes inside of
 128-byte region [ffff88809bbde480, ffff88809bbde500)
The buggy address belongs to the page:
page:ffffea00026ef780 count:1 mapcount:0 mapping:ffff88813bff0640 index:0x0
flags: 0xfff00000000100(slab)
raw: 00fff00000000100 ffffea00026b1708 ffffea0002ccfc88 ffff88813bff0640
raw: 0000000000000000 ffff88809bbde000 0000000100000015 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809bbde380: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
 ffff88809bbde400: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
>ffff88809bbde480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff88809bbde500: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff88809bbde580: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
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