Re: [PATCH net 1/3] igc: pad preemptible packets before reserving TX timestamps

[Paul Moses]

On Monday, October 26th, 2026 at 4:20 AM, netdev-bot+sinfo@xxxxxxxxxx <netdev-bot+sinfo@xxxxxxxxxx> wrote:

> Hi!
> 
> This is an automated message. This series looks like a fix, but its
> commit messages seem to be missing some information:
> 
>  - How the issue was discovered, e.g. hit in production, hit during
>    development, syzbot report, manual code inspection, LLM or static
>    analysis tool scan.
> 
>  - Whether the issue was actually triggered, or is only theoretical
>    (e.g. found by code inspection). If it was triggered please include
>    the symptoms, like the stack trace or error messages.
> 
>  - What hardware the change was tested on. For driver fixes please
>    mention the device (and if relevant firmware version) used for
>    testing, or say that the change was not tested on real hardware.
> 
> Please do not repost the series just to address the above. Instead,
> reply to this email with the missing information, so that reviewers
> can take it into account. If the series needs another revision for
> other reasons, please include the information in the commit messages
> then.
> 
> The evaluation is done by an LLM so it may be wrong, if you think
> that is the case please reply and explain.
> 

Originally found during igc development.

[11865.112180] kernel BUG at pskb_expand_head+0x3f3/0x400 [verbose debug info unavailable]
[11865.112206] Oops: invalid opcode: 0000 [#1] SMP NOPTI
[11865.324662] CPU: 7 UID: 0 PID: 91702 Comm: t Not tainted 7.3.0-rc6-nokasan+ #5 PREEMPT
[11865.429202] RIP: 0010:pskb_expand_head+0x3f3/0x400
[11865.486782] Code: 00 48 83 c7 08 e8 dd da ab ff e9 d2 fd ff ff 4c 8b ab c0 00 00 00 44 8b b3 bc 00 00 00 43 0f b6 44 35 00 e9 89 fd ff ff 0f 0b <0f> 0b 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90
[11865.712331] RSP: 0018:ffffaaf3029077e8 EFLAGS: 00010202
[11865.775131] RAX: 0000000000000002 RBX: ffff9e3260c92920 RCX: 0000000000000820
[11865.860902] RDX: 00000000ffffffc6 RSI: 0000000000000000 RDI: ffff9e3260c92920
[11865.946667] RBP: 0000000000000001 R08: 0000000000000003 R09: 0000000000000001
[11866.032435] R10: 0000000000000000 R11: ffffffffc060c8e0 R12: ffff9e3260c92994
[11866.118206] R13: 0000000000000140 R14: 0000000000000005 R15: 000000000000003c
[11866.203979] FS:  00007860e5343e78(0000) GS:ffff9e3770bd5000(0000) knlGS:0000000000000000
[11866.301224] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[11866.370293] CR2: 00007860e531ac90 CR3: 00000005a7e60002 CR4: 0000000000f70ef0
[11866.456051] PKRU: 55555554
[11866.488599] Call Trace:
[11866.518015]  <TASK>
[11866.543266]  __skb_pad+0xbf/0x130
[11866.583116]  igc_xmit_frame+0x428/0xec0 [igc]
[11866.635491]  ? netif_skb_features+0x230/0x330
[11866.687859]  dev_hard_start_xmit+0x9e/0x1b0
[11866.738142]  sch_direct_xmit+0xde/0x260
[11866.784249]  ? __dev_queue_xmit+0x99/0xf20
[11866.833495]  __dev_queue_xmit+0x77d/0xf20
[11866.881698]  ip_finish_output2+0x310/0x390
[11866.930951]  ip_output+0x64/0x100
[11866.970811]  __ip_queue_xmit+0x485/0x4a0
[11867.017973]  ? __skb_clone+0x2a/0x120
[11867.062009]  __tcp_transmit_skb+0xa79/0xc80
[11867.112299]  tcp_write_xmit+0x849/0x1090
[11867.159463]  __tcp_push_pending_frames+0x32/0xc0
[11867.214967]  tcp_sendmsg_locked+0xeb3/0x1110
[11867.266312]  tcp_sendmsg+0x2c/0x50
[11867.307211]  __sock_sendmsg+0x67/0x90
[11867.351251]  __sys_sendto+0x242/0x290
[11867.395277]  __x64_sys_sendto+0x26/0x30
[11867.441393]  do_syscall_64+0xdb/0x310
[11867.485420]  ? do_syscall_64+0x42/0x310
[11867.531533]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[11867.592248] RIP: 0033:0x7860e532f19d
[11867.635231] Code: c0 0f 85 24 00 00 00 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 <c3> e9 1d bb ff ff cc cc cc cc cc cc cc cc cc cc cc cc cc 41 56 53
[11867.860798] RSP: 002b:00007ffdb9a150e8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
[11867.951782] RAX: ffffffffffffffda RBX: 000000000000002c RCX: 00007860e532f19d
[11868.037552] RDX: 0000000000000001 RSI: 00007ffdb9a1514f RDI: 0000000000000003
[11868.123327] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[11868.209105] R10: 0000000000000000 R11: 0000000000000246 R12: 00007860e5343e78
[11868.294873] R13: 00007ffdb9a151c0 R14: 0000000000000000 R15: 00007860e5343eb4
[11868.380648]  </TASK>

Tested on I210 and I225-V