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=-13.5 required=3.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED,DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,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 3B410C433FE for ; Sat, 11 Sep 2021 11:36:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 14B40610C9 for ; Sat, 11 Sep 2021 11:36:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235733AbhIKLiE (ORCPT ); Sat, 11 Sep 2021 07:38:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53888 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230249AbhIKLiD (ORCPT ); Sat, 11 Sep 2021 07:38:03 -0400 Received: from mail-wm1-x32b.google.com (mail-wm1-x32b.google.com [IPv6:2a00:1450:4864:20::32b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 80C80C061574; Sat, 11 Sep 2021 04:36:50 -0700 (PDT) Received: by mail-wm1-x32b.google.com with SMTP id u15-20020a05600c19cf00b002f6445b8f55so3143563wmq.0; Sat, 11 Sep 2021 04:36:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=0yvDQfJe0Tp73tQcpqCV/x6QPx5VUgyY/ghBBw/JXl4=; b=QkkNVwhk8ES7mIAYxQ/p9xu2di89bCsgfFnxsXtiXXyCoGiA7NYEDbuX+j9trrph6e cy3vpOEbqQ7tc1OxfH0OTZhN4DqEl7hxA+lzT2KdNzpZQ9qW5OA66PMI+yU4ULpacZ1y GqgygqroaC5pb9Wo5MT+t4yjHknwNDTmnaApU7b5/vIWbseBBdpWzQp4CHQxvmMzvtn+ pEF1sPEihKq8axXWoW2y0CN6QI1bdHHMSvf5qwrVKsumBCCAEgDC+VwHetGmhgB4JnKx 8GktyMXW/8QSO+I3DhzrFriPDKKUc5uM1Myt59hnvTPmpYoj97hXS9oPYdplLjhM/gef qKwg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=0yvDQfJe0Tp73tQcpqCV/x6QPx5VUgyY/ghBBw/JXl4=; b=cMRxptPOaGteG1Zb9v58d4H88X3J6Mcqrc1O8sKTfWNmT70EhO2v/JH9DESUBIO7EM 0nJqSregJJorCYFVFHva3Ue4is4byOqFnZT342W6AIUEvCuV67P+JCMCKSp08b+WNaW+ HNfec67YtUkk0TidWIZkyeyJyBjTkh8sT0QEPNgJyjN580gZsQB+tvOVsRVi74E/OOLR 3tE678jVM4kFM8sKZkRsyT64+LR9QurlW81HGVhtvqEbPSMAjLrLzdmQUAR+qBYI7kTm 6LA4JSAzyPU17HE0fvCodZv0j5euwXiVXZ1xxrJ8kCnVFujNc/lDi7v9adWTq1qQMZIV kI8A== X-Gm-Message-State: AOAM532HqtvZQLaB8dmS2PDGzon3u7bspY2n7mwbF5GJGVtRbF5UA2uj WBUezRqU1jdVV1kMEopvBXY= X-Google-Smtp-Source: ABdhPJzBqoNgAuR+ISotUmdYRp3ifg40ubzwDx2OIVPArZLSnjiN6VdiVNUAyuju7w7nbuN0d83gkA== X-Received: by 2002:a1c:9846:: with SMTP id a67mr2377602wme.148.1631360209060; Sat, 11 Sep 2021 04:36:49 -0700 (PDT) Received: from stewarton.broadband ([84.67.150.141]) by smtp.googlemail.com with ESMTPSA id z1sm1373317wmi.34.2021.09.11.04.36.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 11 Sep 2021 04:36:48 -0700 (PDT) From: Iain Hunter Cc: lothar.felten@gmail.com, iain@hunterembedded.co.uk, Jonathan Cameron , Lars-Peter Clausen , Alexandru Ardelean , Matt Ranostay , Gwendal Grignou , linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] workaround regression in ina2xx introduced by cb47755725da("time: Prevent undefined behaviour in timespec64_to_ns()") Date: Sat, 11 Sep 2021 12:36:23 +0100 Message-Id: <20210911113645.2547272-1-drhunter95@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Iain Hunter That change adds an error check to avoid saturation during multiplication to calculate nano seconds in timespec64_to_ns(). In ina2xx_capture_thread() a timespec64 structure is used to calculate the delta time until the next sample time. This delta can be negative if the next sample time was in the past. In the -1 case timespec64_to_ns() now clamps the -1 second value to KTIME_MAX. This essentially puts ina2xx thread to sleep forever. Proposed patch is to replace the call to timespec64_to_ns() with the contents of that function without the overflow test introduced by the commit (ie revert to pre kernel 5.4 behaviour) Signed-off-by: Iain Hunter --- drivers/iio/adc/ina2xx-adc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/iio/adc/ina2xx-adc.c b/drivers/iio/adc/ina2xx-adc.c index a4b2ff9e0..ba3e98fde 100644 --- a/drivers/iio/adc/ina2xx-adc.c +++ b/drivers/iio/adc/ina2xx-adc.c @@ -777,6 +777,7 @@ static int ina2xx_capture_thread(void *data) int ret; struct timespec64 next, now, delta; s64 delay_us; + s64 delta_ns; /* * Poll a bit faster than the chip internal Fs, in case @@ -818,7 +819,8 @@ static int ina2xx_capture_thread(void *data) do { timespec64_add_ns(&next, 1000 * sampling_us); delta = timespec64_sub(next, now); - delay_us = div_s64(timespec64_to_ns(&delta), 1000); + delta_ns = (((s64)delta.tv_sec) * NSEC_PER_SEC)+delta.tv_nsec; + delay_us = div_s64(delta_ns, 1000); } while (delay_us <= 0); usleep_range(delay_us, (delay_us * 3) >> 1); -- 2.17.1