Re: [syzbot] [rds?] general protection fault in rds_tcp_accept_one

[syzbot <syzbot+96046021045ffe6d7709@syzkaller.appspotmail.com>]

> #syz test: git@github.com:allisonhenderson/rds_work.git syzbug_f9db6ff27b9bfdcfeca

unknown command "test:\u00a0git@github.com:allisonhenderson/rds_work.git"

>
> On Mon, 2026-02-09 at 07:41 -0800, syzbot wrote:
>> Hello,
>> 
>> syzbot found the following issue on:
>> 
>> HEAD commit:    9845cf73f7db Add linux-next specific files for 20260205
>> git tree:       linux-next
>> console output: https://urldefense.com/v3/__https://syzkaller.appspot.com/x/log.txt?x=10ec4a5a580000__;!!ACWV5N9M2RV99hQ!K_RGm2D82-xIWkLzauTj3sBwaawib22UgF_b8fgxnoaxBHyflpW7ZtPngueJO7Nq3URYRRJKnpBDOWMXYm8yacLC6gvYGl89kv9Z4ONYVS2j$ 
>> kernel config:  https://urldefense.com/v3/__https://syzkaller.appspot.com/x/.config?x=ac78ce3b6729749e__;!!ACWV5N9M2RV99hQ!K_RGm2D82-xIWkLzauTj3sBwaawib22UgF_b8fgxnoaxBHyflpW7ZtPngueJO7Nq3URYRRJKnpBDOWMXYm8yacLC6gvYGl89kv9Z4NL_GIpI$ 
>> dashboard link: https://urldefense.com/v3/__https://syzkaller.appspot.com/bug?extid=96046021045ffe6d7709__;!!ACWV5N9M2RV99hQ!K_RGm2D82-xIWkLzauTj3sBwaawib22UgF_b8fgxnoaxBHyflpW7ZtPngueJO7Nq3URYRRJKnpBDOWMXYm8yacLC6gvYGl89kv9Z4MCjo-m3$ 
>> compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
>> syz repro:      https://urldefense.com/v3/__https://syzkaller.appspot.com/x/repro.syz?x=122acb22580000__;!!ACWV5N9M2RV99hQ!K_RGm2D82-xIWkLzauTj3sBwaawib22UgF_b8fgxnoaxBHyflpW7ZtPngueJO7Nq3URYRRJKnpBDOWMXYm8yacLC6gvYGl89kv9Z4GW8gg30$ 
>> C reproducer:   https://urldefense.com/v3/__https://syzkaller.appspot.com/x/repro.c?x=149fc7fa580000__;!!ACWV5N9M2RV99hQ!K_RGm2D82-xIWkLzauTj3sBwaawib22UgF_b8fgxnoaxBHyflpW7ZtPngueJO7Nq3URYRRJKnpBDOWMXYm8yacLC6gvYGl89kv9Z4D5oQKmF$ 
>> 
>> Downloadable assets:
>> disk image: https://urldefense.com/v3/__https://storage.googleapis.com/syzbot-assets/9f30334a2431/disk-9845cf73.raw.xz__;!!ACWV5N9M2RV99hQ!K_RGm2D82-xIWkLzauTj3sBwaawib22UgF_b8fgxnoaxBHyflpW7ZtPngueJO7Nq3URYRRJKnpBDOWMXYm8yacLC6gvYGl89kv9Z4OnpjEj3$ 
>> vmlinux: https://urldefense.com/v3/__https://storage.googleapis.com/syzbot-assets/0d58741a15a6/vmlinux-9845cf73.xz__;!!ACWV5N9M2RV99hQ!K_RGm2D82-xIWkLzauTj3sBwaawib22UgF_b8fgxnoaxBHyflpW7ZtPngueJO7Nq3URYRRJKnpBDOWMXYm8yacLC6gvYGl89kv9Z4MX_62da$ 
>> kernel image: https://urldefense.com/v3/__https://storage.googleapis.com/syzbot-assets/62204da1452c/bzImage-9845cf73.xz__;!!ACWV5N9M2RV99hQ!K_RGm2D82-xIWkLzauTj3sBwaawib22UgF_b8fgxnoaxBHyflpW7ZtPngueJO7Nq3URYRRJKnpBDOWMXYm8yacLC6gvYGl89kv9Z4OvQrNJd$ 
>> 
>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>> Reported-by: syzbot+96046021045ffe6d7709@syzkaller.appspotmail.com
>> 
>> netdevsim netdevsim1 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
>> Oops: general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] SMP KASAN PTI
>> KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
>> CPU: 1 UID: 0 PID: 3485 Comm: kworker/u8:8 Not tainted syzkaller #0 PREEMPT(full) 
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
>> Workqueue: krdsd rds_tcp_accept_worker
>> RIP: 0010:rds_tcp_accept_one+0xa5b/0xd70 net/rds/tcp_listen.c:319
>> Code: 00 00 48 83 c3 18 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 63 a9 2f f7 48 8b 1b 48 83 c3 12 49 89 de 49 c1 ee 03 <43> 0f b6 04 2e 84 c0 0f 85 53 02 00 00 44 0f b6 2b bf 08 00 00 00
>> RSP: 0018:ffffc9000b64f9a0 EFLAGS: 00010202
>> RAX: 1ffff1100dacb173 RBX: 0000000000000012 RCX: 0000000000000000
>> RDX: 0000000000000006 RSI: ffffffff8e006fa9 RDI: 00000000ffffffff
>> RBP: ffffc9000b64fb18 R08: ffffffff903342b7 R09: 1ffffffff2066856
>> R10: dffffc0000000000 R11: fffffbfff2066857 R12: ffff88803286c000
>> R13: dffffc0000000000 R14: 0000000000000002 R15: 1ffff920016c9f3c
>> FS:  0000000000000000(0000) GS:ffff888125115000(0000) knlGS:0000000000000000
>> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 00007f30359456b8 CR3: 00000000320ee000 CR4: 00000000003526f0
>> Call Trace:
>>  <TASK>
>>  rds_tcp_accept_worker+0x1d/0x70 net/rds/tcp.c:524
>>  process_one_work+0x949/0x1650 kernel/workqueue.c:3279
>>  process_scheduled_works kernel/workqueue.c:3362 [inline]
>>  worker_thread+0xb46/0x1140 kernel/workqueue.c:3443
>>  kthread+0x388/0x470 kernel/kthread.c:467
>>  ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
>>  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
>>  </TASK>
>> Modules linked in:
>> ---[ end trace 0000000000000000 ]---
>> RIP: 0010:rds_tcp_accept_one+0xa5b/0xd70 net/rds/tcp_listen.c:319
>> Code: 00 00 48 83 c3 18 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 63 a9 2f f7 48 8b 1b 48 83 c3 12 49 89 de 49 c1 ee 03 <43> 0f b6 04 2e 84 c0 0f 85 53 02 00 00 44 0f b6 2b bf 08 00 00 00
>> RSP: 0018:ffffc9000b64f9a0 EFLAGS: 00010202
>> RAX: 1ffff1100dacb173 RBX: 0000000000000012 RCX: 0000000000000000
>> RDX: 0000000000000006 RSI: ffffffff8e006fa9 RDI: 00000000ffffffff
>> RBP: ffffc9000b64fb18 R08: ffffffff903342b7 R09: 1ffffffff2066856
>> R10: dffffc0000000000 R11: fffffbfff2066857 R12: ffff88803286c000
>> R13: dffffc0000000000 R14: 0000000000000002 R15: 1ffff920016c9f3c
>> FS:  0000000000000000(0000) GS:ffff888125115000(0000) knlGS:0000000000000000
>> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 00007f303594da08 CR3: 000000000e74c000 CR4: 00000000003526f0
>> ----------------
>> Code disassembly (best guess):
>>    0:	00 00                	add    %al,(%rax)
>>    2:	48 83 c3 18          	add    $0x18,%rbx
>>    6:	48 89 d8             	mov    %rbx,%rax
>>    9:	48 c1 e8 03          	shr    $0x3,%rax
>>    d:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1)
>>   12:	74 08                	je     0x1c
>>   14:	48 89 df             	mov    %rbx,%rdi
>>   17:	e8 63 a9 2f f7       	call   0xf72fa97f
>>   1c:	48 8b 1b             	mov    (%rbx),%rbx
>>   1f:	48 83 c3 12          	add    $0x12,%rbx
>>   23:	49 89 de             	mov    %rbx,%r14
>>   26:	49 c1 ee 03          	shr    $0x3,%r14
>> * 2a:	43 0f b6 04 2e       	movzbl (%r14,%r13,1),%eax <-- trapping instruction
>>   2f:	84 c0                	test   %al,%al
>>   31:	0f 85 53 02 00 00    	jne    0x28a
>>   37:	44 0f b6 2b          	movzbl (%rbx),%r13d
>>   3b:	bf 08 00 00 00       	mov    $0x8,%edi
>> 
>> 
>> ---
>> This report is generated by a bot. It may contain errors.
>> See https://urldefense.com/v3/__https://goo.gl/tpsmEJ__;!!ACWV5N9M2RV99hQ!K_RGm2D82-xIWkLzauTj3sBwaawib22UgF_b8fgxnoaxBHyflpW7ZtPngueJO7Nq3URYRRJKnpBDOWMXYm8yacLC6gvYGl89kv9Z4Ko4o2Xm$  for more information about syzbot.
>> syzbot engineers can be reached at syzkaller@googlegroups.com.
>> 
>> syzbot will keep track of this issue. See:
>> https://urldefense.com/v3/__https://goo.gl/tpsmEJ*status__;Iw!!ACWV5N9M2RV99hQ!K_RGm2D82-xIWkLzauTj3sBwaawib22UgF_b8fgxnoaxBHyflpW7ZtPngueJO7Nq3URYRRJKnpBDOWMXYm8yacLC6gvYGl89kv9Z4AUXdFJu$  for how to communicate with syzbot.
>> 
>> If the report is already addressed, let syzbot know by replying with:
>> #syz fix: exact-commit-title
>> 
>> If you want syzbot to run the reproducer, reply with:
>> #syz test: git://repo/address.git branch-or-commit-hash
>> If you attach or paste a git patch, syzbot will apply it before testing.
>> 
>> If you want to overwrite report's subsystems, reply with:
>> #syz set subsystems: new-subsystem
>> (See the list of subsystem names on the web dashboard)
>> 
>> If the report is a duplicate of another one, reply with:
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>> 
>> If you want to undo deduplication, reply with:
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>