From patchwork Tue Aug 6 17:46:47 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Waiman Long X-Patchwork-Id: 817479 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 A32626F2E2 for ; Tue, 6 Aug 2024 17:47:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722966453; cv=none; b=qHr/ewA5JCam0rvl3ep/DQqdoqgvXbe+KDE3lokPPuMAhyqO6ouUBk1voIHFnb+w6HJkqhBP1+H8/0tO9kdZIS0pw7xPLCBvyxhOF8NbtSHQP3ceFTWTKPlL1GuAYR7qm183N2R85l7NyHolX62tA9J0WtqmDVSnR3dpVx/njzg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722966453; c=relaxed/simple; bh=m8zP/G2Caope01Y5hp+XNPX61CFNQXC42ATl15aCd2U=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=h+mxxN/BuXLEuIkTVsB1cMkGR7e01sMzK+dCp5EyxwtWhnVTtkCf6moHMVpFM6SHjfww0un/iaH1oRDaF9vLG0Op09wD4kv3yqbdAyST+OJB8Dg1XoiSQj/DW5fDPRTdefjpvNi/tyFv8JMT8DMfhOfTB/xHlCBKWpyyieMA/yI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=IQEdXKtg; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="IQEdXKtg" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1722966450; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=Dx3lp9LD5waJbHKy20MWljw9mO6ZuZv40UA8MNp3kCs=; b=IQEdXKtgSsqcf9gwZth3qnVHa1muaJ8mhm6T/hyqeM8GNnJEepfL+peBFCvAvj68ge4jco 1COVOlU4Ndxa06K0x8QS8km/ObpljjYG+OP1e75DvPzbdABvlIcgp5KsC/s6sYAmFjlgHE LRENkmX8fP73LkzTCRQgl1vu6nT7304= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-145-rCRjMDKNMH2L5EfFmof1eA-1; Tue, 06 Aug 2024 13:47:29 -0400 X-MC-Unique: rCRjMDKNMH2L5EfFmof1eA-1 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id DBACE19560A2; Tue, 6 Aug 2024 17:47:27 +0000 (UTC) Received: from llong.com (unknown [10.2.16.146]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 226F8300019B; Tue, 6 Aug 2024 17:47:25 +0000 (UTC) From: Waiman Long To: Steffen Klassert , Daniel Jordan , Andrew Morton Cc: linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, Waiman Long Subject: [PATCH] padata: Fix possible divide-by-0 panic in padata_mt_helper() Date: Tue, 6 Aug 2024 13:46:47 -0400 Message-ID: <20240806174647.1050398-1-longman@redhat.com> Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 We are hit with a not easily reproducible divide-by-0 panic in padata.c at bootup time. [ 10.017908] Oops: divide error: 0000 1 PREEMPT SMP NOPTI [ 10.017908] CPU: 26 PID: 2627 Comm: kworker/u1666:1 Not tainted 6.10.0-15.el10.x86_64 #1 [ 10.017908] Hardware name: Lenovo ThinkSystem SR950 [7X12CTO1WW]/[7X12CTO1WW], BIOS [PSE140J-2.30] 07/20/2021 [ 10.017908] Workqueue: events_unbound padata_mt_helper [ 10.017908] RIP: 0010:padata_mt_helper+0x39/0xb0 : [ 10.017963] Call Trace: [ 10.017968] [ 10.018004] ? padata_mt_helper+0x39/0xb0 [ 10.018084] process_one_work+0x174/0x330 [ 10.018093] worker_thread+0x266/0x3a0 [ 10.018111] kthread+0xcf/0x100 [ 10.018124] ret_from_fork+0x31/0x50 [ 10.018138] ret_from_fork_asm+0x1a/0x30 [ 10.018147] Looking at the padata_mt_helper() function, the only way a divide-by-0 panic can happen is when ps->chunk_size is 0. The way that chunk_size is initialized in padata_do_multithreaded(), chunk_size can be 0 when the min_chunk in the passed-in padata_mt_job structure is 0. Fix this divide-by-0 panic by making sure that chunk_size will be at least 1 no matter what the input parameters are. Fixes: 004ed42638f4 ("padata: add basic support for multithreaded jobs") Signed-off-by: Waiman Long --- kernel/padata.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/padata.c b/kernel/padata.c index 53f4bc912712..0fa6c2895460 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -517,6 +517,13 @@ void __init padata_do_multithreaded(struct padata_mt_job *job) ps.chunk_size = max(ps.chunk_size, job->min_chunk); ps.chunk_size = roundup(ps.chunk_size, job->align); + /* + * chunk_size can be 0 if the caller sets min_chunk to 0. So force it + * to at least 1 to prevent divide-by-0 panic in padata_mt_helper().` + */ + if (!ps.chunk_size) + ps.chunk_size = 1U; + list_for_each_entry(pw, &works, pw_list) if (job->numa_aware) { int old_node = atomic_read(&last_used_nid);