[syzbot] BUG: "hc->tx_t_ipi == NUM" holds (exception!) at net/dccp/ccids/ccid3.c:LINE/ccid3_update_s

Hello,

syzbot found the following issue on:

HEAD commit:    82192cb497f9 Merge branch 'ena-capabilities-field-and-cosm..
git tree:       net-next
console output: https://syzkaller.appspot.com/x/log.txt?xec95c7b00000
kernel config:  https://syzkaller.appspot.com/x/.config?x22a0a6462d9ff7d
dashboard link: https://syzkaller.appspot.com/bug?extid”641ba6c1d768b1e35e
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x0ea4e3b00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x977b73b00000

Bisection is inconclusive: the issue happens on the oldest tested release.

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x698c63b00000
final oops:     https://syzkaller.appspot.com/x/report.txt?xe98c63b00000
console output: https://syzkaller.appspot.com/x/log.txt?x698c63b00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]

BUG: "hc->tx_t_ipi = 0" holds (exception!) at net/dccp/ccids/ccid3.c:90/ccid3_update_send_interval()
CPU: 0 PID: 29976 Comm: syz-executor890 Not tainted 5.16.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 ccid3_update_send_interval net/dccp/ccids/ccid3.c:90 [inline]
 ccid3_update_send_interval.cold+0x87/0x93 net/dccp/ccids/ccid3.c:86
 ccid3_hc_tx_update_s net/dccp/ccids/ccid3.c:169 [inline]
 ccid3_hc_tx_packet_sent+0x12e/0x160 net/dccp/ccids/ccid3.c:353
 ccid_hc_tx_packet_sent net/dccp/ccid.h:175 [inline]
 dccp_xmit_packet+0x2f2/0x750 net/dccp/output.c:289
 dccp_write_xmit+0x16d/0x1d0 net/dccp/output.c:366
 dccp_sendmsg+0x922/0xc90 net/dccp/proto.c:783
 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:819
 sock_sendmsg_nosec net/socket.c:705 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:725
 ____sys_sendmsg+0x331/0x810 net/socket.c:2413
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2467
 __sys_sendmmsg+0x195/0x470 net/socket.c:2553
 __do_sys_sendmmsg net/socket.c:2582 [inline]
 __se_sys_sendmmsg net/socket.c:2579 [inline]
 __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2579
 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+0x44/0xae
RIP: 0033:0x7f2cf5f36da9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f2cf5ee4308 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f2cf5f36da9
RDX: 0000000000000001 RSI: 000000002000bf40 RDI: 0000000000000004
RBP: 00007f2cf5fbf4c8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2cf5fbf4c0
R13: 00007f2cf5f8c5dc R14: 00007f2cf5ee4400 R15: 0000000000022000
 </TASK>


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