[syzbot] UBSAN: array-index-out-of-bounds in taprio_change

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    36a21d51725a Linux 5.14-rc5
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=127f3379300000
kernel config:  https://syzkaller.appspot.com/x/.config?x=730106bfb5bf8ace
dashboard link: https://syzkaller.appspot.com/bug?extid=2b3e5fb6c7ef285a94f6
compiler:       Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.1

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2b3e5fb6c7ef285a94f6@xxxxxxxxxxxxxxxxxxxxxxxxx

UBSAN: array-index-out-of-bounds in net/sched/sch_taprio.c:1519:10
index 16 is out of range for type '__u16 [16]'
CPU: 0 PID: 13032 Comm: syz-executor.2 Not tainted 5.14.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1d3/0x29f lib/dump_stack.c:105
 ubsan_epilogue lib/ubsan.c:148 [inline]
 __ubsan_handle_out_of_bounds+0xdb/0x130 lib/ubsan.c:288
 taprio_change+0x33d0/0x5c90 net/sched/sch_taprio.c:1519
 qdisc_create+0x7c2/0x1480 net/sched/sch_api.c:1247
 tc_modify_qdisc+0xa88/0x1ea0 net/sched/sch_api.c:1646
 rtnetlink_rcv_msg+0x91c/0xe50 net/core/rtnetlink.c:5574
 netlink_rcv_skb+0x1f0/0x460 net/netlink/af_netlink.c:2504
 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
 netlink_unicast+0x7de/0x9b0 net/netlink/af_netlink.c:1340
 netlink_sendmsg+0x9e7/0xe00 net/netlink/af_netlink.c:1929
 sock_sendmsg_nosec net/socket.c:703 [inline]
 sock_sendmsg net/socket.c:723 [inline]
 ____sys_sendmsg+0x5a2/0x900 net/socket.c:2392
 ___sys_sendmsg net/socket.c:2446 [inline]
 __sys_sendmsg+0x319/0x400 net/socket.c:2475
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665e9
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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f399085a188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665e9
RDX: 0000000000000000 RSI: 00000000200007c0 RDI: 0000000000000007
RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80
R13: 00007ffe9b94383f R14: 00007f399085a300 R15: 0000000000022000
================================================================================


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