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=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_RED, 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 1358CC433E0 for ; Mon, 28 Dec 2020 13:07:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D680F221F0 for ; Mon, 28 Dec 2020 13:07:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730463AbgL1NHr (ORCPT ); Mon, 28 Dec 2020 08:07:47 -0500 Received: from mail.kernel.org ([198.145.29.99]:34784 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729617AbgL1NHE (ORCPT ); Mon, 28 Dec 2020 08:07:04 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 94D1E21D94; Mon, 28 Dec 2020 13:06:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609160783; bh=ZC7jmSmNoxuf+N+gxg4VQ1KIKXp32QeS8eSK5iclPyg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UNt0p0rtqDVTItnsZNSQoHofppfEqSsOgvTUyn+xmF7CB4x05S4kFX2TLEYip0XTF RA1up6iDR5i0rXwQPrOcmnFQLaZWa6hWVQ0ST8ozp63QQ/US30xH3G/MA1rfeW5Wha uQafaqw6mx+fhA3/QnHXoxNHkN8LatLQth+Nacws= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, =?UTF-8?q?Nuno=20S=C3=A1?= , Stable@vger.kernel.org, Jonathan Cameron Subject: [PATCH 4.9 170/175] iio: buffer: Fix demux update Date: Mon, 28 Dec 2020 13:50:23 +0100 Message-Id: <20201228124901.462790066@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201228124853.216621466@linuxfoundation.org> References: <20201228124853.216621466@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Nuno Sá commit 19ef7b70ca9487773c29b449adf0c70f540a0aab upstream. When updating the buffer demux, we will skip a scan element from the device in the case `in_ind != out_ind` and we enter the while loop. in_ind should only be refreshed with `find_next_bit()` in the end of the loop. Note, to cause problems we need a situation where we are skippig over an element (channel not enabled) that happens to not have the same size as the next element. Whilst this is a possible situation we haven't actually identified any cases in mainline where it happens as most drivers have consistent channel storage sizes with the exception of the timestamp which is the last element and hence never skipped over. Fixes: 5ada4ea9be16 ("staging:iio: add demux optionally to path from device to buffer") Signed-off-by: Nuno Sá Link: https://lore.kernel.org/r/20201112144323.28887-1-nuno.sa@analog.com Cc: Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman --- drivers/iio/industrialio-buffer.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/drivers/iio/industrialio-buffer.c +++ b/drivers/iio/industrialio-buffer.c @@ -1335,12 +1335,12 @@ static int iio_buffer_update_demux(struc indio_dev->masklength, in_ind + 1); while (in_ind != out_ind) { - in_ind = find_next_bit(indio_dev->active_scan_mask, - indio_dev->masklength, - in_ind + 1); length = iio_storage_bytes_for_si(indio_dev, in_ind); /* Make sure we are aligned */ in_loc = roundup(in_loc, length) + length; + in_ind = find_next_bit(indio_dev->active_scan_mask, + indio_dev->masklength, + in_ind + 1); } length = iio_storage_bytes_for_si(indio_dev, in_ind); out_loc = roundup(out_loc, length);