XPost: linux.debian.bugs.dist
From: kerneljasonxing@gmail.com
Hi,
On Mon, Oct 20, 2025 at 12:50 PM mc36 wrote:
>
> hi,
>
> freertr.org xsk dataplane is triggering a null pointer de-reference after
sending
>
> a single ip packet from user space to an xsk socket bound to a veth
interface.
>
> the same code works fine when using physical interfaces to send packets to...
>
> it does not matter if an ip address is assigned to the veth pair or not...
>
> please find below the reproducer code with some comments on how to use it...
>
> tldr: create a veth pair, bring them up, compile and run the c code...
>
> this happens 10/10 on host or in qemu-system-x86_64-kvm running 6.16.12 or
6.17.2...
Thanks for the report.
I'm wondering if you have time to bisect which recent commit has
brought this problem. It looks like it never happens before 6.16?
Thanks,
Jason
>
> if it does not belongs here, just let me know....
>
> have a nice day,
>
> csaba
>
>
> ------------------------------------------------------[cut]---
-----------------------------------------------------
>
>
> p4emu login: [ 119.074634] BUG: kernel NULL pointer dereference, address:
0000000000000000
> [ 119.076747] #PF: supervisor read access in kernel mode
> [ 119.078334] #PF: error_code(0x0000) - not-present page
> [ 119.079855] PGD 0 P4D 0
> [ 119.080648] Oops: Oops: 0000 [#1] SMP NOPTI
> [ 119.081993] CPU: 2 UID: 1 PID: 927 Comm: p4xsk.bin Not tainted
6.16.12+deb14-cloud-amd64 #1 PREEMPT(lazy) Debian 6.16.12-1
> [ 119.085247] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.17.0-debian-1.17.0-1 04/01/2014
> [ 119.088065] RIP: 0010:xsk_destruct_skb+0xd0/0x180
> [ 119.089502] Code: 40 10 48 89 cf 89 28 e8 9e 7e 07 00 48 89 df 48 83 c4
18 5b 5d 41 5c 41 5d 41 5e 41 5f e9 c8 cc da ff 48 8b 7b 30 4c 8d 5b 30 <48>
8b 07 4c 8d 67 f8 4c 8d 70
> f8 49 39 fb 74 b7 48 89 5c 24 10 4c
> [ 119.094947] RSP: 0018:ffffcd5b4012cd48 EFLAGS: 00010002
> [ 119.096499] RAX: ffffcd5b40fcf000 RBX: ffff898e05dfcf00 RCX:
ffff898e043cf9e8
> [ 119.098612] RDX: ffff898e048ccc80 RSI: 0000000000000246 RDI:
0000000000000000
> [ 119.100687] RBP: 0000000000000001 R08: 0000000000000000 R09:
ffff898e01d21900
> [ 119.102794] R10: 0000000000000000 R11: ffff898e05dfcf30 R12:
ffff898e05f95000
> [ 119.104880] R13: ffff898e043cf900 R14: ffff898e7dd32bd0 R15:
0000000000000002
> [ 119.107000] FS: 00007f0cd9e0a6c0(0000) GS:ffff898ede530000(0000)
knlGS:0000000000000000
> [ 119.109358] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 119.111080] CR2: 0000000000000000 CR3: 00000000043ba003 CR4:
0000000000372ef0
> [ 119.113175] Call Trace:
> [ 119.113996]
> [ 119.114662] ? napi_complete_done+0x7a/0x1a0
> [ 119.115952] ip_rcv_core+0x1bb/0x340
> [ 119.117050] ip_rcv+0x30/0x1f0
> [ 119.118014] __netif_receive_skb_one_core+0x85/0xa0
> [ 119.119468] process_backlog+0x87/0x130
> [ 119.120617] __napi_poll+0x28/0x180
> [ 119.121685] net_rx_action+0x339/0x420
> [ 119.122850] handle_softirqs+0xdc/0x320
> [ 119.124003] ? handle_edge_irq+0x90/0x1e0
> [ 119.125218] do_softirq.part.0+0x3b/0x60
> [ 119.126422]
> [ 119.127085]
> [ 119.127753] __local_bh_enable_ip+0x60/0x70
> [ 119.128998] __dev_direct_xmit+0x14e/0x1f0
> [ 119.130128] __xsk_generic_xmit+0x482/0xb70
> [ 119.131184] ? __remove_hrtimer+0x41/0xa0
> [ 119.132199] ? __xsk_generic_xmit+0x51/0xb70
> [ 119.133300] ? _raw_spin_unlock_irqrestore+0xe/0x40
> [ 119.134637] xsk_sendmsg+0xda/0x1c0
> [ 119.135580] __sys_sendto+0x1ee/0x200
> [ 119.136509] __x64_sys_sendto+0x24/0x30
> [ 119.137493] do_syscall_64+0x84/0x2f0
> [ 119.138452] ? __pfx_pollwake+0x10/0x10
> [ 119.139454] ? __rseq_handle_notify_resume+0xad/0x4c0
> [ 119.140718] ? restore_fpregs_from_fpstate+0x3c/0x90
> [ 119.141999] ? switch_fpu_return+0x5b/0xe0
> [ 119.143023] ? do_syscall_64+0x204/0x2f0
> [ 119.144007] ? do_syscall_64+0x204/0x2f0
> [ 119.144990] ? do_syscall_64+0x204/0x2f0
> [ 119.146022] entry_SYSCALL_64_after_hwframe+0x76/0x7e
> [ 119.147278] RIP: 0033:0x7f0cde0a49ee
> [ 119.148217] Code: 08 0f 85 f5 4b ff ff 49 89 fb 48 89 f0 48 89 d7 48 89
ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05
66 2e 0f 1f 84 00 00 00 00
> 00 0f 1f 80 00 00 00 00 48 83 ec 08
> [ 119.152877] RSP: 002b:00007f0cd9e09c98 EFLAGS: 00000246 ORIG_RAX:
000000000000002c
> [ 119.154774] RAX: ffffffffffffffda RBX: 00007f0cd9e0a6c0 RCX:
00007f0cde0a49ee
> [ 119.156526] RDX: 0000000000000000 RSI: 0000000000000000 RDI:
0000000000000029
[continued in next message]
--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)
|
