Subject: Re: [syzbot] [rds?] WARNING in rds_conn_connect_if_down

From: syzbot <[email-masked]>
Date: Tue, 27 Feb 2024 06:58:19 -0800

syzbot has found a reproducer for the following issue on:

HEAD commit:    25d434257464 Merge branch 'pcs-xpcs-cleanups'
git tree:       net-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=11f0034a180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=57c41f64f37f51c5
dashboard link: https://syzkaller.appspot.com/bug?extid=d4faee732755bba9838e
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11cbd722180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10ff934a180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2731aa9fb143/disk-25d43425.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d1daf5663559/vmlinux-25d43425.xz
kernel image: https://storage.googleapis.com/syzbot-assets/798446e4189b/bzImage-25d43425.xz

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

------------[ cut here ]------------
WARNING: CPU: 0 PID: 5244 at net/rds/connection.c:931 rds_conn_connect_if_down+0x95/0xb0 net/rds/connection.c:931
Modules linked in:
CPU: 0 PID: 5244 Comm: syz-executor403 Not tainted 6.8.0-rc5-syzkaller-01592-g25d434257464 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
RIP: 0010:rds_conn_connect_if_down+0x95/0xb0 net/rds/connection.c:931
Code: 00 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 2e c3 42 f7 49 8b 3e 5b 41 5e 41 5f e9 f1 fa ff ff e8 ac 49 e0 f6 90 <0f> 0b 90 eb cb 89 d9 80 e1 07 38 c1 7c a9 48 89 df e8 75 c2 42 f7
RSP: 0018:ffffc900042cf8a0 EFLAGS: 00010293
RAX: ffffffff8ab323c4 RBX: 0000000000000002 RCX: ffff888021100000
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000000
RBP: ffffc900042cfad0 R08: ffffffff8ab3238b R09: ffffffff8ab44361
R10: 0000000000000002 R11: ffff888021100000 R12: ffff8880746ee000
R13: ffff88802e39a6c0 R14: ffff8880260f2000 R15: dffffc0000000000
FS:  00007f8c89bff6c0(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000002069d000 CR3: 000000002989a000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 rds_sendmsg+0x1409/0x2280 net/rds/send.c:1319
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:745
 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2584
 ___sys_sendmsg net/socket.c:2638 [inline]
 __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667
 do_syscall_64+0xf9/0x240
 entry_SYSCALL_64_after_hwframe+0x6f/0x77
RIP: 0033:0x7f8c89c84519
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 61 1a 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8c89bff218 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f8c89d0e428 RCX: 00007f8c89c84519
RDX: 0000000000000000 RSI: 0000000020000800 RDI: 0000000000000003
RBP: 00007f8c89d0e420 R08: 00007ffeca3c5797 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f8c89d0e42c
R13: 00007f8c89cdb4f4 R14: 732e79726f6d656d R15: 00007ffeca3c5798
 </TASK>

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