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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 F07DEC3A59F for ; Sun, 18 Aug 2019 01:47:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C5ACC21773 for ; Sun, 18 Aug 2019 01:47:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566092877; bh=ChAVdJpNLOryLOHbb3Di/mHnhmC5olD86fEm37XBG2Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=raX+4fT19yrGlij6fRMumwVIoFctq42xFDfItmILIWKvjQIMkslg5nby501r9rTDU 1eb00Wbvw1HER5hdWX66BQQHbLtCy9VAHGbFTJUBE9c9yPp16Q8tbtk/xL1soBD0tF B7enMn5HQUXPKLegsI6gLwCVVlrolu6v2daJDuhw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726513AbfHRBr5 (ORCPT ); Sat, 17 Aug 2019 21:47:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:54318 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726463AbfHRBr4 (ORCPT ); Sat, 17 Aug 2019 21:47:56 -0400 Received: from localhost (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5A3972086C; Sun, 18 Aug 2019 01:47:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566092875; bh=ChAVdJpNLOryLOHbb3Di/mHnhmC5olD86fEm37XBG2Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=KXwHHxunnE2XJaI4MsPpbWNswT0MoXe46Aegh6eQyTKR0cZU2bGR75KCt8qeIAZRy Krba46V3X39/Kj00cUWW2yQpkuN5zu46CLZ9INRyWf7z3k+OlUXaFn8QEKkZS9Jdo1 EqEWYzBeSxHdXaQYrX9Z8dGe1cUvnWhJg5pM+++8= Date: Sat, 17 Aug 2019 21:47:54 -0400 From: Sasha Levin To: David Laight Cc: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" , Colin Ian King , Inki Dae , "dri-devel@lists.freedesktop.org" Subject: Re: [PATCH AUTOSEL 5.2 51/59] drm/exynos: fix missing decrement of retry counter Message-ID: <20190818014754.GE1318@sasha-vm> References: <20190806213319.19203-1-sashal@kernel.org> <20190806213319.19203-51-sashal@kernel.org> <2ecde45912fc44b88df2ff5129b8ab67@AcuMS.aculab.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <2ecde45912fc44b88df2ff5129b8ab67@AcuMS.aculab.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 07, 2019 at 08:49:52AM +0000, David Laight wrote: >From: Sasha Levin >> Sent: 06 August 2019 22:33 >> >> From: Colin Ian King >> >> [ Upstream commit 1bbbab097a05276e312dd2462791d32b21ceb1ee ] >> >> Currently the retry counter is not being decremented, leading to a >> potential infinite spin if the scalar_reads don't change state. >> >> Addresses-Coverity: ("Infinite loop") >> Fixes: 280e54c9f614 ("drm/exynos: scaler: Reset hardware before starting the operation") >> Signed-off-by: Colin Ian King >> Signed-off-by: Inki Dae >> Signed-off-by: Sasha Levin >> --- >> drivers/gpu/drm/exynos/exynos_drm_scaler.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/gpu/drm/exynos/exynos_drm_scaler.c b/drivers/gpu/drm/exynos/exynos_drm_scaler.c >> index ec9c1b7d31033..8989f8af716b7 100644 >> --- a/drivers/gpu/drm/exynos/exynos_drm_scaler.c >> +++ b/drivers/gpu/drm/exynos/exynos_drm_scaler.c >> @@ -94,12 +94,12 @@ static inline int scaler_reset(struct scaler_context *scaler) >> scaler_write(SCALER_CFG_SOFT_RESET, SCALER_CFG); >> do { >> cpu_relax(); >> - } while (retry > 1 && >> + } while (--retry > 1 && >> scaler_read(SCALER_CFG) & SCALER_CFG_SOFT_RESET); >> do { >> cpu_relax(); >> scaler_write(1, SCALER_INT_EN); >> - } while (retry > 0 && scaler_read(SCALER_INT_EN) != 1); >> + } while (--retry > 0 && scaler_read(SCALER_INT_EN) != 1); >> >> return retry ? 0 : -EIO; > >If the first loop hits the retry limit the second loop won't be right >and the final return value will be 0. This looks like an upstream problem as well, no? -- Thanks, Sasha