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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9F229C67871 for ; Mon, 16 Jan 2023 16:21:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232916AbjAPQVp (ORCPT ); Mon, 16 Jan 2023 11:21:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37962 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232976AbjAPQVE (ORCPT ); Mon, 16 Jan 2023 11:21:04 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 656C629E04 for ; Mon, 16 Jan 2023 08:11:37 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id F108460FDF for ; Mon, 16 Jan 2023 16:11:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0AB36C433D2; Mon, 16 Jan 2023 16:11:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1673885496; bh=EVKbeqe3sVmz6gPyK4px4cwHaORxjGRRhkXAONP5Kmk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wIuru6tWriFSCZsmilsk/Uc8cKLCDWQC8uHLqwlBxVArZvvRElcBFld2e17Xyi3j4 0t287im//5lhi3hvQmIIgSi+2uais486N0WAPkub5jOUkqhyXo08TqX+yJ0G+6ywfa bJIP6RyiEZMc+z0oO+JMNX82NR5QkOa0Jwuyf1pE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Wolfram Sang , Jonathan Corbet , Sasha Levin Subject: [PATCH 5.4 074/658] docs: fault-injection: fix non-working usage of negative values Date: Mon, 16 Jan 2023 16:42:42 +0100 Message-Id: <20230116154913.012061081@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230116154909.645460653@linuxfoundation.org> References: <20230116154909.645460653@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Wolfram Sang [ Upstream commit 005747526d4f3c2ec995891e95cb7625161022f9 ] Fault injection uses debugfs in a way that the provided values via sysfs are interpreted as u64. Providing negative numbers results in an error: /sys/kernel/debug/fail_function# echo -1 > times sh: write error: Invalid argument Update the docs and examples to use "printf %#x " in these cases. For "retval", reword the paragraph a little and fix a typo. Signed-off-by: Wolfram Sang Link: https://lore.kernel.org/r/20210603125841.27436-1-wsa+renesas@sang-engineering.com Signed-off-by: Jonathan Corbet Stable-dep-of: d472cf797c4e ("debugfs: fix error when writing negative value to atomic_t debugfs file") Signed-off-by: Sasha Levin --- .../fault-injection/fault-injection.rst | 24 +++++++++++-------- 1 file changed, 14 insertions(+), 10 deletions(-) diff --git a/Documentation/fault-injection/fault-injection.rst b/Documentation/fault-injection/fault-injection.rst index f51bb21d20e4..e4056dc51e7f 100644 --- a/Documentation/fault-injection/fault-injection.rst +++ b/Documentation/fault-injection/fault-injection.rst @@ -74,8 +74,10 @@ configuration of fault-injection capabilities. - /sys/kernel/debug/fail*/times: - specifies how many times failures may happen at most. - A value of -1 means "no limit". + specifies how many times failures may happen at most. A value of -1 + means "no limit". Note, though, that this file only accepts unsigned + values. So, if you want to specify -1, you better use 'printf' instead + of 'echo', e.g.: $ printf %#x -1 > times - /sys/kernel/debug/fail*/space: @@ -163,11 +165,13 @@ configuration of fault-injection capabilities. - ERRNO: retval must be -1 to -MAX_ERRNO (-4096). - ERR_NULL: retval must be 0 or -1 to -MAX_ERRNO (-4096). -- /sys/kernel/debug/fail_function//retval: +- /sys/kernel/debug/fail_function//retval: - specifies the "error" return value to inject to the given - function for given function. This will be created when - user specifies new injection entry. + specifies the "error" return value to inject to the given function. + This will be created when the user specifies a new injection entry. + Note that this file only accepts unsigned values. So, if you want to + use a negative errno, you better use 'printf' instead of 'echo', e.g.: + $ printf %#x -12 > retval Boot option ^^^^^^^^^^^ @@ -250,7 +254,7 @@ Application Examples echo Y > /sys/kernel/debug/$FAILTYPE/task-filter echo 10 > /sys/kernel/debug/$FAILTYPE/probability echo 100 > /sys/kernel/debug/$FAILTYPE/interval - echo -1 > /sys/kernel/debug/$FAILTYPE/times + printf %#x -1 > /sys/kernel/debug/$FAILTYPE/times echo 0 > /sys/kernel/debug/$FAILTYPE/space echo 2 > /sys/kernel/debug/$FAILTYPE/verbose echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-wait @@ -304,7 +308,7 @@ Application Examples echo N > /sys/kernel/debug/$FAILTYPE/task-filter echo 10 > /sys/kernel/debug/$FAILTYPE/probability echo 100 > /sys/kernel/debug/$FAILTYPE/interval - echo -1 > /sys/kernel/debug/$FAILTYPE/times + printf %#x -1 > /sys/kernel/debug/$FAILTYPE/times echo 0 > /sys/kernel/debug/$FAILTYPE/space echo 2 > /sys/kernel/debug/$FAILTYPE/verbose echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-wait @@ -331,11 +335,11 @@ Application Examples FAILTYPE=fail_function FAILFUNC=open_ctree echo $FAILFUNC > /sys/kernel/debug/$FAILTYPE/inject - echo -12 > /sys/kernel/debug/$FAILTYPE/$FAILFUNC/retval + printf %#x -12 > /sys/kernel/debug/$FAILTYPE/$FAILFUNC/retval echo N > /sys/kernel/debug/$FAILTYPE/task-filter echo 100 > /sys/kernel/debug/$FAILTYPE/probability echo 0 > /sys/kernel/debug/$FAILTYPE/interval - echo -1 > /sys/kernel/debug/$FAILTYPE/times + printf %#x -1 > /sys/kernel/debug/$FAILTYPE/times echo 0 > /sys/kernel/debug/$FAILTYPE/space echo 1 > /sys/kernel/debug/$FAILTYPE/verbose -- 2.35.1