Regression on linux-next (next-20250304)

Regression on linux-next (next-20250304)

[Borah, Chaitanya Kumar]

Hello Li,

Hope you are doing well. I am Chaitanya from the linux graphics team in Intel.

This mail is regarding a regression we are seeing in our CI runs[1] on linux-next repository.

Since the version next-20250304 [2], we are seeing the following regression

`````````````````````````````````````````````````````````````````````````````````
<1> [45.775074] BUG: unable to handle page fault for address: ffff8884d9a1e000
<1> [45.775076] #PF: supervisor read access in kernel mode
<1> [45.775077] #PF: error_code(0x0000) - not-present page
<6> [45.775078] PGD 8201067 P4D 8201067 PUD 0 
<4> [45.775080] Oops: Oops: 0000 [#1] PREEMPT SMP PTI
<4> [45.775083] CPU: 10 UID: 0 PID: 1320 Comm: fbdev Tainted: G     U              6.14.0-rc5-next-20250307-next-20250307-g0a2f88912896+ #1
<4> [45.775085] Tainted: [U]=USER
<4> [45.775086] Hardware name: Intel Corporation CoffeeLake Client Platform/CoffeeLake S UDIMM RVP, BIOS CNLSFWR1.R00.X220.B00.2103302221 03/30/2021
<4> [45.775087] RIP: 0010:intel_bts_disable_local+0x14/0x50
`````````````````````````````````````````````````````````````````````````````````
Details log can be found in [3].

We suspect the following patch [4] causes the issue.

`````````````````````````````````````````````````````````````````````````````````````````````````````````
commit 3acfcefa795c6cfb08c68467060bd7aa30557077
Author: Li RongQing mailto:lirongqing@baidu.com
Date:   Wed Jan 22 15:41:03 2025 +0800

    perf/x86/intel/bts: Allocate bts_ctx only if necessary
`````````````````````````````````````````````````````````````````````````````````````````````````````````

We also verified that if we revert the patch the issue is not seen.

Could you please check why the patch causes this regression and provide a fix if necessary?

Thank you.

Regards

Chaitanya

[1] https://intel-gfx-ci.01.org/tree/linux-next/combined-alt.html?
[2] https://web.git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?h=next-20250304
[3] https://intel-gfx-ci.01.org/tree/linux-next/next-20250307/bat-dg2-8/igt@fbdev@read.html
[4] https://web.git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?h=next-20250304&id=3acfcefa795c6cfb08c68467060bd7aa30557077

答复: [????] Regression on linux-next (next-20250304)

[Li,Rongqing]

> Hello Li,
> 
> Hope you are doing well. I am Chaitanya from the linux graphics team in Intel.
> 
>

This has been fixed by

https://web.git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=7a310c644cf571fbdb1d447a1dc39cf048634589

Thanks

-Li

RE: [????] Regression on linux-next (next-20250304)

[Borah, Chaitanya Kumar]

> -----Original Message-----
> From: Li,Rongqing <lirongqing@baidu.com>
> Sent: Wednesday, March 12, 2025 6:58 AM
> To: Borah, Chaitanya Kumar <chaitanya.kumar.borah@intel.com>
> Cc: linux-perf-users@vger.kernel.org; intel-gfx@lists.freedesktop.org; intel-
> xe@lists.freedesktop.org; Kurmi, Suresh Kumar
> <suresh.kumar.kurmi@intel.com>; Saarinen, Jani <jani.saarinen@intel.com>;
> Hunter, Adrian <adrian.hunter@intel.com>; kan.liang@linux.intel.com
> Subject: 答复: [????] Regression on linux-next (next-20250304)
> 
> > Hello Li,
> >
> > Hope you are doing well. I am Chaitanya from the linux graphics team in
> Intel.
> >
> >
> 
> This has been fixed by
> 
> https://web.git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=7a
> 310c644cf571fbdb1d447a1dc39cf048634589

Thank you for the reply. Will it make its way to linux-next?

Regards

Chaitanya

> 
> Thanks
> 
> -Li