From patchwork Thu Jan 10 21:09:47 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Khalid Aziz X-Patchwork-Id: 10756939 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C5DA913B5 for ; Thu, 10 Jan 2019 21:12:29 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B1E4029BA0 for ; Thu, 10 Jan 2019 21:12:29 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A330F29BE7; Thu, 10 Jan 2019 21:12:29 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id D615229BA0 for ; Thu, 10 Jan 2019 21:12:28 +0000 (UTC) Received: (qmail 13485 invoked by uid 550); 10 Jan 2019 21:11:13 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 13367 invoked from network); 10 Jan 2019 21:11:12 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : in-reply-to : references; s=corp-2018-07-02; bh=un0wieK7yWFodUoPf/TbQJCMffDoPehxHgZRzLFUW2o=; b=chPszpAiJAbkg+zkadcOBGkMBvHUigW7P3J5U9kXh/4WR4WaTdIqSIJKmzOC/NYFDsyM MrFViq/HYuHukuzNxvfAtgv5S+929Mdu9AdazByjvd+OPJMDXYmo8iFtHbKf7joRxxl/ QVImhgrAo9iB2tmKxcqYcyE2n9GTsgn+pHOsq5kbq0i5OjnVPX2uEIwCk/3vgDm7ck2L gdt2Jf6KBycEqmPAG9bKtRrQvpN6O6xgeHZxhQyKMbbVoWzO9mVK92OnrDy3zK7hhBVl 4ErVypdkvqQImbKrKUjb7pLwtF16Ii9FhyFfMXHHcbV30+4FHsmkdvwuL+W2nUMEn+cL gQ== From: Khalid Aziz To: juergh@gmail.com, tycho@tycho.ws, jsteckli@amazon.de, ak@linux.intel.com, torvalds@linux-foundation.org, liran.alon@oracle.com, keescook@google.com, konrad.wilk@oracle.com Cc: Khalid Aziz , deepa.srinivasan@oracle.com, chris.hyser@oracle.com, tyhicks@canonical.com, dwmw@amazon.co.uk, andrew.cooper3@citrix.com, jcm@redhat.com, boris.ostrovsky@oracle.com, kanth.ghatraju@oracle.com, joao.m.martins@oracle.com, jmattson@google.com, pradeep.vincent@oracle.com, john.haxby@oracle.com, tglx@linutronix.de, kirill.shutemov@linux.intel.com, hch@lst.de, steven.sistare@oracle.com, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [RFC PATCH v7 15/16] xpfo, mm: Fix hang when booting with "xpfotlbflush" Date: Thu, 10 Jan 2019 14:09:47 -0700 Message-Id: X-Mailer: git-send-email 2.17.1 In-Reply-To: References: In-Reply-To: References: X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9132 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1901100164 X-Virus-Scanned: ClamAV using ClamSMTP Kernel hangs when booted up with "xpfotlbflush" option. This is caused by xpfo_kunmap() fliushing TLB while holding xpfo lock starving other tasks waiting for the lock. This patch moves tlb flush outside of the code holding xpfo lock. Signed-off-by: Khalid Aziz --- mm/xpfo.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/mm/xpfo.c b/mm/xpfo.c index 85079377c91d..79ffdba6af69 100644 --- a/mm/xpfo.c +++ b/mm/xpfo.c @@ -148,6 +148,8 @@ EXPORT_SYMBOL(xpfo_kmap); void xpfo_kunmap(void *kaddr, struct page *page) { + bool flush_tlb = false; + if (!static_branch_unlikely(&xpfo_inited)) return; @@ -168,10 +170,13 @@ void xpfo_kunmap(void *kaddr, struct page *page) if (atomic_read(&page->xpfo_mapcount) == 0) { SetPageXpfoUnmapped(page); set_kpte(kaddr, page, __pgprot(0)); - xpfo_cond_flush_kernel_tlb(page, 0); + flush_tlb = true; } spin_unlock(&page->xpfo_lock); } + + if (flush_tlb) + xpfo_cond_flush_kernel_tlb(page, 0); } EXPORT_SYMBOL(xpfo_kunmap);