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=-18.8 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_BLOCKED, USER_AGENT_GIT 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 D33A0C433DB for ; Fri, 22 Jan 2021 20:14:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9E27623AFC for ; Fri, 22 Jan 2021 20:14:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731091AbhAVUOf (ORCPT ); Fri, 22 Jan 2021 15:14:35 -0500 Received: from mail.kernel.org ([198.145.29.99]:34616 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727517AbhAVOKm (ORCPT ); Fri, 22 Jan 2021 09:10:42 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 62C9823A75; Fri, 22 Jan 2021 14:09:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1611324563; bh=sOkpxDdA5DSQyv9tafJKuk6w3gPd/pNyDXBhe+5YM5Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=b7DaDFSzUIfk1flcaH88nzeN8shJvagyh7bk1Z7D6/7TecTtcUF+/lyfeUb3QKdhy Puc/5T5H9lF+W+uWYUuxx/1RmVGSPFZXq4O6WHSL/u9n+hDyUZ7k82FUJb4FtVrLov 4b2YIGqFjGYMRa3oJplcFXCLQM//hGYZftp/wqDg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, =?UTF-8?q?Nuno=20S=E1?= , Stable@vger.kernel.org, Jonathan Cameron , Sudip Mukherjee Subject: [PATCH 4.4 21/31] iio: buffer: Fix demux update Date: Fri, 22 Jan 2021 15:08:35 +0100 Message-Id: <20210122135732.717616060@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210122135731.873346566@linuxfoundation.org> References: <20210122135731.873346566@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 [sudip: adjust context] Signed-off-by: Sudip Mukherjee 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 @@ -1281,9 +1281,6 @@ 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); ch = iio_find_channel_from_si(indio_dev, in_ind); if (ch->scan_type.repeat > 1) length = ch->scan_type.storagebits / 8 * @@ -1292,6 +1289,9 @@ static int iio_buffer_update_demux(struc length = ch->scan_type.storagebits / 8; /* 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); } ch = iio_find_channel_from_si(indio_dev, in_ind); if (ch->scan_type.repeat > 1)