From: bot+bpf-ci@kernel.org
To: tj@kernel.org,void@manifault.com,arighi@nvidia.com,changwoo@igalia.com
Cc: emil@etsalapatis.com,david.dai@linux.dev,yonghong.song@linux.dev,ast@kernel.org,bpf@vger.kernel.org,sched-ext@lists.linux.dev,linux-kernel@vger.kernel.org,ast@kernel.org,andrii@kernel.org,daniel@iogearbox.net,martin.lau@kernel.org,eddyz87@gmail.com,yonghong.song@linux.dev,mason@kernel.org,ihor.solodrai@linux.dev
Subject: Re: [PATCH sched_ext/for-7.4] sched_ext: Work around pahole 1.32 dropping scx_bpf_task_set_lazy_resched() from BTF
Date: Wed, 30 Sep 2026 00:59:02 +0000 (UTC) [thread overview]
Message-ID: <92a44bb46f421bebc4ab85faa0f95944cbb9d877d8e9372f51cfaae358841d2b@mail.kernel.org> (raw)
In-Reply-To: <7c139810be5ffc9764ed4236efc28794@kernel.org>
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> sched_ext: Work around pahole 1.32 dropping scx_bpf_task_set_lazy_resched() from BTF
>
> With clang and pahole 1.32, x86-64 vmlinux BTF lacks
> scx_bpf_task_set_lazy_resched() and sched_ext fails to initialize:
>
> sched_ext: Failed to register kfunc sets (-22)
>
> clang describes the lazy argument only after the prologue moves it into a
> callee-saved register, which pahole 1.32 rejects as not being the argument
> register. Released pahole is affected whatever the eventual fix. Keep the
> argument on the stack with barrier_data() so that its location names no
> register. OPTIMIZER_HIDE_VAR() would fix x86-64 but break arm64.
>
> Fixes: f8e5a4e3f3be ("sched_ext: Add lazy preemption support")
Does the Fixes tag reference a commit that exists in this branch's history?
The tag points to f8e5a4e3f3be, but if that commit is not an ancestor of
this commit, the Fixes tag would be referencing a commit from a different
tree or branch.
Can you verify that f8e5a4e3f3be is reachable from this commit's history,
or clarify which commit in this branch originally introduced the lazy
preemption support that needs the workaround?
---
AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md
CI run summary: https://github.com/kernel-patches/bpf/actions/runs/36651688234
prev parent reply other threads:[~2026-09-30 0:59 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-29 17:32 Tejun Heo
2026-09-29 19:19 ` Andrea Righi
2026-09-29 19:25 ` Tejun Heo
2026-09-29 19:37 ` Andrea Righi
2026-09-29 23:11 ` Tejun Heo
2026-09-30 0:59 ` bot+bpf-ci [this message]
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