From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 016A652CCD8; Tue, 29 Sep 2026 17:32:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790703149; cv=none; b=no7yHzqz2KheC5EcW9De5UDm+b522425ieR1z4FZD8LaeItpnApMGXD/rW98pxL6CZjg6Edc/GWrBGZpsUJLa5ZQcnPxHGssoOajA1M3FYsFpe0EcL+EfFggfZze78D5qt+aHNsesEh3NKHfCg7cu0OwGR6OvGN7yDHrSxZyhx4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790703149; c=relaxed/simple; bh=3TZ8g5UCZHMa88MVXJ635FkC/44FvB2ynhkEJHzRIzk=; h=Date:Message-ID:From:To:Cc:Subject; b=u2k+/b9RscTeiX6nwXTYhNfbE7WS17Q3qZcaZjxDMe2ZqY/FRYEhGZFhYoWauo3fqaCpvcpCoNkMy7+mB13Ss84gwox3hurGfsQiAswW7VBv8eD7K2dfEaVmYJ9qwBZqPl9BxOaBHHYFDyAviGudtoIAwF8iRnccj9tu+nboUs0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=P47vVT9X; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="P47vVT9X" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 634121F000FF; Tue, 29 Sep 2026 17:32:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790703147; bh=CINuwoEbhNpzdGEObXiChmnQ1GyrltWXLggIbeowDI0=; h=Date:From:To:Cc:Subject; b=P47vVT9XU43/wBQnCRmW3o3kuVH4HCZ3ebQ3TrRphxPJdAo2zC2EOtzCgS3UHP/2v QIkZTWFJuuJczCCu5EvAwr7qat9zMUgQiXOGPFs8U9gf9QNuGGRQxP5K0slqeKMqAh AtI63pDZqioG9RZG3vUIm7Qrv6LS85QFt8K2N1cwZn45qu351cerwsZLQiRUqr7ARw Zn4kJaeyTmEC6fIc5mdLLHquOqpvRiqHXoghNdn+GXEbWKXhviKRKPWKZMJ/LYcUFM sIB4QIG8A+enV3D1Yig0ZD5uD0A98zfv/KHLYHV0xxoxW6YK27H8xl9eo7x4PMQYQm S+ZW/84nb7HMg== Date: Tue, 29 Sep 2026 07:32:26 -1000 Message-ID: <7c139810be5ffc9764ed4236efc28794@kernel.org> From: Tejun Heo To: David Vernet , Andrea Righi , Changwoo Min Cc: Emil Tsalapatis , David Dai , Yonghong Song , Alexei Starovoitov , bpf@vger.kernel.org, sched-ext@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH sched_ext/for-7.4] sched_ext: Work around pahole 1.32 dropping scx_bpf_task_set_lazy_resched() from BTF Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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") Link: https://lore.kernel.org/r/20260925213619.2187751-1-yonghong.song@linux.dev Signed-off-by: Tejun Heo --- kernel/sched/ext/ext.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/kernel/sched/ext/ext.c +++ b/kernel/sched/ext/ext.c @@ -10136,6 +10136,11 @@ __bpf_kfunc bool scx_bpf_task_set_lazy_r { struct scx_sched *sch; + /* + * clang's register locations for @lazy make pahole 1.32 drop this kfunc + * from BTF. Keep @lazy in memory so its location names no register. + */ + barrier_data(&lazy); guard(rcu)(); sch = scx_prog_sched(aux); if (unlikely(!sch || !scx_task_on_sched(sch, p)))