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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 CB170C43441 for ; Sun, 11 Nov 2018 20:07:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 959352080D for ; Sun, 11 Nov 2018 20:07:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 959352080D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=decadent.org.uk 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 S1731442AbeKLF4i (ORCPT ); Mon, 12 Nov 2018 00:56:38 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:52080 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727208AbeKLF4i (ORCPT ); Mon, 12 Nov 2018 00:56:38 -0500 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1gLvtB-0000l9-3S; Sun, 11 Nov 2018 19:59:21 +0000 Received: from ben by deadeye with local (Exim 4.91) (envelope-from ) id 1gLvsP-0001QN-3M; Sun, 11 Nov 2018 19:58:33 +0000 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, syzbot+cd8bcd40cb049efa2770@syzkaller.appspotmail.com, "Laura Abbott" , "syzbot" , "Greg Kroah-Hartman" Date: Sun, 11 Nov 2018 19:49:05 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 054/366] staging: android: ion: Switch to pr_warn_once in ion_buffer_destroy In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.61-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Laura Abbott commit 45ad559a29629cb1c64ee636563c69b71524f077 upstream. Syzbot reported yet another warning with Ion: WARNING: CPU: 0 PID: 1467 at drivers/staging/android/ion/ion.c:122 ion_buffer_destroy+0xd4/0x190 drivers/staging/android/ion/ion.c:122 Kernel panic - not syncing: panic_on_warn set ... This is catching that a buffer was freed with an existing kernel mapping still present. This can be easily be triggered from userspace by calling DMA_BUF_SYNC_START without calling DMA_BUF_SYNC_END. Switch to a single pr_warn_once to indicate the error without being disruptive. Reported-by: syzbot+cd8bcd40cb049efa2770@syzkaller.appspotmail.com Reported-by: syzbot Signed-off-by: Laura Abbott Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- drivers/staging/android/ion/ion.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/drivers/staging/android/ion/ion.c +++ b/drivers/staging/android/ion/ion.c @@ -272,8 +272,11 @@ err2: void ion_buffer_destroy(struct ion_buffer *buffer) { - if (WARN_ON(buffer->kmap_cnt > 0)) + if (buffer->kmap_cnt > 0) { + pr_warn_once("%s: buffer still mapped in the kernel\n", + __func__); buffer->heap->ops->unmap_kernel(buffer->heap, buffer); + } buffer->heap->ops->unmap_dma(buffer->heap, buffer); buffer->heap->ops->free(buffer); if (buffer->pages)