From patchwork Thu May 6 14:26:58 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andreas Gruenbacher X-Patchwork-Id: 12242225 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 86DFCC433ED for ; Thu, 6 May 2021 14:27:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6D03C613B5 for ; Thu, 6 May 2021 14:27:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234653AbhEFO2E (ORCPT ); Thu, 6 May 2021 10:28:04 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:29011 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234002AbhEFO2E (ORCPT ); Thu, 6 May 2021 10:28:04 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1620311225; 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=x3AOZuJBE2nH0EU6wAcRHTGc+AikyM2yp8+U3sVbjOc=; b=He5MN/CHuwW4qlEDrg/Jt2UpqTFy5Fd3Yr87qUVied25/stJQ1l8IVaUWwQq+MoQGcZ7kj BrVKoiJLPHVvFzslvRN7LsCj3puiT+MGsVhQTfgoIMKb1h7LmRr86GBlNmoOFDDIOmV+Z4 UjmOJfuAOn3zdylqBVGdZVKVxEvi+0A= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-580-TIgsaXVYMhy1mcM_fdrbPw-1; Thu, 06 May 2021 10:27:02 -0400 X-MC-Unique: TIgsaXVYMhy1mcM_fdrbPw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 280B118BA280; Thu, 6 May 2021 14:27:01 +0000 (UTC) Received: from max.com (unknown [10.40.195.97]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0771C19D61; Thu, 6 May 2021 14:26:59 +0000 (UTC) From: Andreas Gruenbacher To: fstests@vger.kernel.org Cc: Andreas Gruenbacher , Jan Kara , stable@vger.kernel.org Subject: [PATCH v2] gfs2: Fix mmap + page fault deadlock Date: Thu, 6 May 2021 16:26:58 +0200 Message-Id: <20210506142658.1077906-1-agruenba@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: fstests@vger.kernel.org Commit 20f829999c38 has moved the inode glock taking from gfs2_readpage and gfs2_readahead into gfs2_file_read_iter and gfs2_fault. In gfs2_fault, we didn't take into account that page faults can occur while holding the inode glock, for example, gfs2_file_read_iter [grabs inode glock] -> generic_file_read_iter -> filemap_read -> copy_page_to_iter ... -> gfs2_fault [tries to grab inode glock again] gfs2_file_write_iter -> iomap_file_buffered_write -> iomap_apply -> iomap_ops->iomap_begin [grabs inode glock] -> iomap_write_actor -> iov_iter_fault_in_readable ... -> gfs2_fault [tries to grab inode glock again] Fix that by checking if we're holding the inode glock already. Reported-by: Jan Kara Fixes: 20f829999c38 ("gfs2: Rework read and page fault locking") Cc: stable@vger.kernel.org # v5.8+ Signed-off-by: Andreas Gruenbacher --- fs/gfs2/file.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c index a0b542d84cd9..95b59763b748 100644 --- a/fs/gfs2/file.c +++ b/fs/gfs2/file.c @@ -538,18 +538,22 @@ static vm_fault_t gfs2_fault(struct vm_fault *vmf) { struct inode *inode = file_inode(vmf->vma->vm_file); struct gfs2_inode *ip = GFS2_I(inode); + bool recursive = gfs2_glock_is_locked_by_me(ip->i_gl); struct gfs2_holder gh; vm_fault_t ret; int err; gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh); - err = gfs2_glock_nq(&gh); - if (err) { - ret = block_page_mkwrite_return(err); - goto out_uninit; + if (likely(!recursive)) { + err = gfs2_glock_nq(&gh); + if (err) { + ret = block_page_mkwrite_return(err); + goto out_uninit; + } } ret = filemap_fault(vmf); - gfs2_glock_dq(&gh); + if (likely(!recursive)) + gfs2_glock_dq(&gh); out_uninit: gfs2_holder_uninit(&gh); return ret;