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@xxxxxxxxx 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@xxxxxxxxx [4] https://web.git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?h=next-20250304&id=3acfcefa795c6cfb08c68467060bd7aa30557077
