From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 AFF2B1C07C4; Tue, 15 Oct 2024 12:58:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728997116; cv=none; b=UAFEvf/MJ/y4L7GIWjbFDvm5wvJNlRYT0Hb9SFX0J1D42L/zN+GoN6WgGhtK4AZXff+He3+txlwvYlyvgKp1Fxz1RRGnOQj6LquSIXM6nDepmsGXAeMOjEU3oMG+IHJKKG6rOVO84k8KDrjBMr7+obGO346TravaAvyEXgdaWgk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728997116; c=relaxed/simple; bh=ysYXStonbOmtYT5gH9e4xKWfMaCN6tiPtE8zytiu+Gk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=TRf/RV2hJZtUI6TLgNbwoCqs58B9NKbkVWX3V1d6ST7AyPk73hb4muAyKNYUa4sr3TyG6mnnWvPYATi9VM/VTLrNf4PMmGOoSZjKKXj3PqAcPZVFH4SeGGkTt5nl7C1sZi9As5xKGoUMDqjFKXasQKPB6dJ98Lp8HpZ1fYxNxTc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=d2qKjYaM; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="d2qKjYaM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1EE3DC4CEC6; Tue, 15 Oct 2024 12:58:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1728997116; bh=ysYXStonbOmtYT5gH9e4xKWfMaCN6tiPtE8zytiu+Gk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=d2qKjYaMkR7d6FxDoFT/Y+CnUnNtR1WYKMKunR+OxSy5WQ7iJ+Tz1nMbE0qTzCg3q PoakjGbf89dJuPCeDxIe337l62BcDcDHm50QtkBCB6td/LC7n0MVLmv4AVDSgtTt0o LwWPiwERgKBH/lFd4MxxI8DDjpaEyHyUF4M921fc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Kamlesh Gurudasani , =?UTF-8?q?=C2=A0=20Waiman=20Long?= , Daniel Jordan , Herbert Xu , Sasha Levin Subject: [PATCH 5.10 065/518] padata: Honor the callers alignment in case of chunk_size 0 Date: Tue, 15 Oct 2024 14:39:29 +0200 Message-ID: <20241015123919.515269611@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241015123916.821186887@linuxfoundation.org> References: <20241015123916.821186887@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kamlesh Gurudasani [ Upstream commit 24cc57d8faaa4060fd58adf810b858fcfb71a02f ] In the case where we are forcing the ps.chunk_size to be at least 1, we are ignoring the caller's alignment. Move the forcing of ps.chunk_size to be at least 1 before rounding it up to caller's alignment, so that caller's alignment is honored. While at it, use max() to force the ps.chunk_size to be at least 1 to improve readability. Fixes: 6d45e1c948a8 ("padata: Fix possible divide-by-0 panic in padata_mt_helper()") Signed-off-by: Kamlesh Gurudasani Acked-by:  Waiman Long Acked-by: Daniel Jordan Signed-off-by: Herbert Xu Signed-off-by: Sasha Levin --- kernel/padata.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/padata.c b/kernel/padata.c index 2a514cf8379b4..41d5bf2fa2ad9 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -516,9 +516,12 @@ void __init padata_do_multithreaded(struct padata_mt_job *job) * thread function. Load balance large jobs between threads by * increasing the number of chunks, guarantee at least the minimum * chunk size from the caller, and honor the caller's alignment. + * Ensure chunk_size is at least 1 to prevent divide-by-0 + * panic in padata_mt_helper(). */ ps.chunk_size = job->size / (ps.nworks * load_balance_factor); ps.chunk_size = max(ps.chunk_size, job->min_chunk); + ps.chunk_size = max(ps.chunk_size, 1ul); ps.chunk_size = roundup(ps.chunk_size, job->align); /* -- 2.43.0