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 CCC5125771; Wed, 2 Oct 2024 13:23:15 +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=1727875395; cv=none; b=CBMM0i9R5OVDb4wHTxSRLfMb8ysEP0L38psSHFLDSB6fm3SD+V0HztksKp6EuCaSLeWjOJtOMP9NUN7l0I9G6Me/bFpT+Q9+wNIjH4jbU46J25ZnKPOZIp0udh43QWvsV3ZfgN1Eunb6VuzAU0cqZUKLVN2pIHmRKQ1+ddJF3e4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727875395; c=relaxed/simple; bh=OXgauTtYtAYaeGtVetKMQZvDvDTuDVy7fPxDjEShmzI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=dhz0g/IFiKtHCRU/MAG5RxA2QolIwz/8vDdyOSPz10waFwMU7Vl4PoYaWCCcHz7ZanHcVDaZFyjxg0SmQu+lhu6hAEMqCs99p2KOW1A3KiTGeItxkIuyKoJbzY9bcADR/tPe/4GaOU4VXDFCtbfBikt0jD/nUlb8KbAQgF3YHFw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=M1XTmyGA; 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="M1XTmyGA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E1E46C4CEC5; Wed, 2 Oct 2024 13:23:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1727875395; bh=OXgauTtYtAYaeGtVetKMQZvDvDTuDVy7fPxDjEShmzI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=M1XTmyGAYrm1Cp1kQUNyd6ScOs2oG49sU40I2osMBeCIOJdwx9E3LxWV8MqEafu+J qeHgzHWpwdASWvu7HS+vt2e+AxxpHp/Gh0wDsG1B9OVqNTQGUgSeY2/px/M43YGmTV BC2wmxXz4r6HzD5nb0P5UQJZJ5egxom61mZX88xQ= 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 6.11 056/695] padata: Honor the callers alignment in case of chunk_size 0 Date: Wed, 2 Oct 2024 14:50:54 +0200 Message-ID: <20241002125824.722532090@linuxfoundation.org> X-Mailer: git-send-email 2.46.2 In-Reply-To: <20241002125822.467776898@linuxfoundation.org> References: <20241002125822.467776898@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.11-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 0fa6c28954603..9e98afe72a334 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -512,9 +512,12 @@ 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