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 X-Spam-Level: X-Spam-Status: No, score=-2.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 835C7C3279B for ; Fri, 6 Jul 2018 21:44:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2C21822B70 for ; Fri, 6 Jul 2018 21:44:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="P/ka28H6" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2C21822B70 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=joelfernandes.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932692AbeGFVo2 (ORCPT ); Fri, 6 Jul 2018 17:44:28 -0400 Received: from mail-pl0-f67.google.com ([209.85.160.67]:41037 "EHLO mail-pl0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932239AbeGFVo1 (ORCPT ); Fri, 6 Jul 2018 17:44:27 -0400 Received: by mail-pl0-f67.google.com with SMTP id w8-v6so3407489ply.8 for ; Fri, 06 Jul 2018 14:44:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=from:to:cc:subject:date:message-id; bh=KrIQAzZyjefIKFQ4uitl5ddkRz/kLtCH2yreZba173Y=; b=P/ka28H6AF24giTrfYp6TurGv4lxHlj6RxRHbcQcILBUw4McUHRo8WsgZqyOVG2Wrt cvE/I5gkiN+os13/GDL8xrlx2BCi4FzuKHxOz/SsL0eBqPArlwrug6Utmir91Ri1/w7h XIR+I4YoL0xXTZ6YxcTlPI0SyOJ4rTCzEfU7M= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=KrIQAzZyjefIKFQ4uitl5ddkRz/kLtCH2yreZba173Y=; b=WqXklTSN/8V2NpAAG6SLNTKGCBadH1ku6e4xnegEAyHwX5qmBq1j5Sd1s8SzYLwEDl RKqDxvN/qaRn1TCllUi1muyplz89R6Z1LDJPeHURXa/av4v5zA73/TZluA7KwAFdenxA A+Agvi66T0NHITlVa86jJLw6ra8Gtej5qmuxFUdgifUK1Q/UU6K1EitKsxJd3UYtAup+ WZ06f6BVRogbBacaUYMzeOpMd4g0oTRIEc0WRnRVrvI7zMExbY6oEauKZ9UfDnWcHXYC USFUrALJn/izoQd15ZVlJ+k54zgA7lQrI2+VrNc+cPBzvmadqM1f50T76mq/g3nKhGJ8 Jg2Q== X-Gm-Message-State: APt69E0PFO6Mu07xIdiQfVr5e9d3rak//RpnViENV1W+tBr4EG50mwFX w4Gyw8syZDMesmnlBZQ5qBjUOFpp9+w= X-Google-Smtp-Source: AAOMgpc+4uUODTaxkJUJsQo+jWqtlbPk6YZskNRI6F2j7ZPoAij9aAe5Qgs0ziIBsSy292DF8kQv/g== X-Received: by 2002:a17:902:28ea:: with SMTP id f97-v6mr11357616plb.55.1530913466700; Fri, 06 Jul 2018 14:44:26 -0700 (PDT) Received: from joelaf.mtv.corp.google.com ([2620:0:1000:1600:3122:ea9c:d178:eb]) by smtp.gmail.com with ESMTPSA id c5-v6sm26967844pfe.169.2018.07.06.14.44.25 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 06 Jul 2018 14:44:25 -0700 (PDT) From: Joel Fernandes To: linux-kernel@vger.kernel.org Cc: kernel-team@android.com, Tobias Lindskog , Jeff Vander Stoep , Joel Fernandes , "Arve H" , devel@driverdev.osuosl.org, Greg Kroah-Hartman , Martijn Coenen , Todd Kjos Subject: [PATCH] ashmem: Shrink directly through shmem_fallocate Date: Fri, 6 Jul 2018 14:44:16 -0700 Message-Id: <20180706214416.184691-1-joel@joelfernandes.org> X-Mailer: git-send-email 2.18.0.203.gfac676dfb9-goog Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Tobias Lindskog When ashmem_shrink is called from direct reclaim on a user thread, a call to do_fallocate will check for permissions against the security policy of that user thread. It can thus fail by chance if called on a thread that isn't permitted to modify the relevant ashmem areas. Because we know that we have a shmem file underneath, call the shmem implementation of fallocate directly instead of going through the user-space interface for fallocate. Bug: 21951515 Signed-off-by: Tobias Lindskog Signed-off-by: Jeff Vander Stoep Signed-off-by: Joel Fernandes (Google) --- drivers/staging/android/ashmem.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/staging/android/ashmem.c b/drivers/staging/android/ashmem.c index a1a0025b59e0..23ff9ee80386 100644 --- a/drivers/staging/android/ashmem.c +++ b/drivers/staging/android/ashmem.c @@ -444,9 +444,9 @@ ashmem_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) loff_t start = range->pgstart * PAGE_SIZE; loff_t end = (range->pgend + 1) * PAGE_SIZE; - vfs_fallocate(range->asma->file, - FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, - start, end - start); + range->asma->file->f_op->fallocate(range->asma->file, + FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, + start, end - start); range->purged = ASHMEM_WAS_PURGED; lru_del(range); -- 2.18.0.203.gfac676dfb9-goog