From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A1A64C46467 for ; Wed, 28 Dec 2022 16:19:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234584AbiL1QTI (ORCPT ); Wed, 28 Dec 2022 11:19:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36734 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234630AbiL1QSk (ORCPT ); Wed, 28 Dec 2022 11:18:40 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E323419C02 for ; Wed, 28 Dec 2022 08:17:16 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 9DD4BB81729 for ; Wed, 28 Dec 2022 16:17:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0CA94C433D2; Wed, 28 Dec 2022 16:17:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1672244234; bh=WWPsSeepMj9dU7XEy/RR7i+5U38bMl9c8y4cnteUs9U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aSMg/Nmzmah62ysEC2Sj4EnZLQnr+1Uw0keuqzIhIwuQ5BxDwKxrrhCFgvka4QfHw f2QbzwPTuMhUWT0HLFQFcMIQyrcB4veSLmGDo3e9o9qKz3v9d4JOCEFThqqCXW2VLD /ORVu+nR5QJcXWBXLPX0svKjM5blSmwkAsHQEH9I= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+bc05445bc14148d51915@syzkaller.appspotmail.com, Daniel Jordan , Steffen Klassert , Herbert Xu , Sasha Levin Subject: [PATCH 6.1 0633/1146] padata: Always leave BHs disabled when running ->parallel() Date: Wed, 28 Dec 2022 15:36:12 +0100 Message-Id: <20221228144347.359775527@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20221228144330.180012208@linuxfoundation.org> References: <20221228144330.180012208@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Daniel Jordan [ Upstream commit 34c3a47d20ae55b3600fed733bf96eafe9c500d5 ] A deadlock can happen when an overloaded system runs ->parallel() in the context of the current task: padata_do_parallel ->parallel() pcrypt_aead_enc/dec padata_do_serial spin_lock(&reorder->lock) // BHs still enabled ... __do_softirq ... padata_do_serial spin_lock(&reorder->lock) It's a bug for BHs to be on in _do_serial as Steffen points out, so ensure they're off in the "current task" case like they are in padata_parallel_worker to avoid this situation. Reported-by: syzbot+bc05445bc14148d51915@syzkaller.appspotmail.com Fixes: 4611ce224688 ("padata: allocate work structures for parallel jobs from a pool") Signed-off-by: Daniel Jordan Acked-by: Steffen Klassert Signed-off-by: Herbert Xu Signed-off-by: Sasha Levin --- kernel/padata.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/kernel/padata.c b/kernel/padata.c index e5819bb8bd1d..97f51e0c1776 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -207,14 +207,16 @@ int padata_do_parallel(struct padata_shell *ps, pw = padata_work_alloc(); spin_unlock(&padata_works_lock); + if (!pw) { + /* Maximum works limit exceeded, run in the current task. */ + padata->parallel(padata); + } + rcu_read_unlock_bh(); if (pw) { padata_work_init(pw, padata_parallel_worker, padata, 0); queue_work(pinst->parallel_wq, &pw->pw_work); - } else { - /* Maximum works limit exceeded, run in the current task. */ - padata->parallel(padata); } return 0; -- 2.35.1