syzbot
general protection fault in rxrpc_kernel_recv_data
Status:
upstream: reported on 2026/08/29 02:56
Reported-by: syzbot+ad230ef43e8fff30e474@syzkaller.appspotmail.com
First crash: 1d15h, last: 1d12h
Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc000000006f: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000378-0x000000000000037f]
CPU: 0 PID: 6260 Comm: kworker/0:12 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: kafsd afs_process_async_call
RIP: 0010:rxrpc_kernel_recv_data+0x5f/0x510 net/rxrpc/recvmsg.c:710
Code: 28 48 bd 00 00 00 00 00 fc ff df e8 9b 1b 72 f8 48 c7 44 24 20 00 00 00 00 4c 8d bb 78 03 00 00 4d 89 fc 49 c1 ec 03 49 89 ee <41> 0f b6 04 2c 84 c0 0f 85 62 03 00 00 41 8b 2f bf 06 00 00 00 89
RSP: 0000:ffffc9000348f9b0 EFLAGS: 00010206
RAX: ffffffff8906f405 RBX: 0000000000000000 RCX: ffff88802a5b5940
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888074712a00
RBP: dffffc0000000000 R08: 0000000000000001 R09: ffffc9000348fa60
R10: dffffc0000000000 R11: ffffed100b1f9627 R12: 000000000000006f
R13: ffff888058fcb120 R14: dffffc0000000000 R15: 0000000000000378
FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b3290fff8 CR3: 000000002b3a0000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
afs_extract_data+0x134/0x650 fs/afs/rxrpc.c:906
afs_deliver_vl_get_capabilities+0x127/0x300 fs/afs/vlclient.c:329
afs_deliver_to_call+0x12b/0x1100 fs/afs/rxrpc.c:510
afs_process_async_call+0x7e/0xe0 fs/afs/rxrpc.c:702
process_one_work+0x867/0xff0 kernel/workqueue.c:2310
worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
kthread+0x42e/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
Modules linked in:
---[ end trace 7c0ff868a4807332 ]---
RIP: 0010:rxrpc_kernel_recv_data+0x5f/0x510 net/rxrpc/recvmsg.c:710
Code: 28 48 bd 00 00 00 00 00 fc ff df e8 9b 1b 72 f8 48 c7 44 24 20 00 00 00 00 4c 8d bb 78 03 00 00 4d 89 fc 49 c1 ec 03 49 89 ee <41> 0f b6 04 2c 84 c0 0f 85 62 03 00 00 41 8b 2f bf 06 00 00 00 89
RSP: 0000:ffffc9000348f9b0 EFLAGS: 00010206
RAX: ffffffff8906f405 RBX: 0000000000000000 RCX: ffff88802a5b5940
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888074712a00
RBP: dffffc0000000000 R08: 0000000000000001 R09: ffffc9000348fa60
R10: dffffc0000000000 R11: ffffed100b1f9627 R12: 000000000000006f
R13: ffff888058fcb120 R14: dffffc0000000000 R15: 0000000000000378
FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd21ec9dc0 CR3: 00000000247f6000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 28 48 bd sub %cl,-0x43(%rax)
3: 00 00 add %al,(%rax)
5: 00 00 add %al,(%rax)
7: 00 fc add %bh,%ah
9: ff lcall (bad)
a: df e8 fucomip %st(0),%st
c: 9b fwait
d: 1b 72 f8 sbb -0x8(%rdx),%esi
10: 48 c7 44 24 20 00 00 movq $0x0,0x20(%rsp)
17: 00 00
19: 4c 8d bb 78 03 00 00 lea 0x378(%rbx),%r15
20: 4d 89 fc mov %r15,%r12
23: 49 c1 ec 03 shr $0x3,%r12
27: 49 89 ee mov %rbp,%r14
* 2a: 41 0f b6 04 2c movzbl (%r12,%rbp,1),%eax <-- trapping instruction
2f: 84 c0 test %al,%al
31: 0f 85 62 03 00 00 jne 0x399
37: 41 8b 2f mov (%r15),%ebp
3a: bf 06 00 00 00 mov $0x6,%edi
3f: 89 .byte 0x89
* Struck through repros no longer work on HEAD.