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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 BD7F2C32751 for ; Wed, 7 Aug 2019 08:49:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9FE0622387 for ; Wed, 7 Aug 2019 08:49:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728930AbfHGIt4 convert rfc822-to-8bit (ORCPT ); Wed, 7 Aug 2019 04:49:56 -0400 Received: from eu-smtp-delivery-151.mimecast.com ([146.101.78.151]:23053 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728473AbfHGItz (ORCPT ); Wed, 7 Aug 2019 04:49:55 -0400 Received: from AcuMS.aculab.com (156.67.243.126 [156.67.243.126]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-219-Xw5AdrD2MRiS34lGOcsHNg-1; Wed, 07 Aug 2019 09:49:52 +0100 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) by AcuMS.aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Wed, 7 Aug 2019 09:49:52 +0100 Received: from AcuMS.Aculab.com ([fe80::43c:695e:880f:8750]) by AcuMS.aculab.com ([fe80::43c:695e:880f:8750%12]) with mapi id 15.00.1347.000; Wed, 7 Aug 2019 09:49:52 +0100 From: David Laight To: 'Sasha Levin' , "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" CC: 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 Thread-Topic: [PATCH AUTOSEL 5.2 51/59] drm/exynos: fix missing decrement of retry counter Thread-Index: AQHVTJ/1OP2tfkMm3E2/Hf9p02kXJabvYCkQ Date: Wed, 7 Aug 2019 08:49:52 +0000 Message-ID: <2ecde45912fc44b88df2ff5129b8ab67@AcuMS.aculab.com> References: <20190806213319.19203-1-sashal@kernel.org> <20190806213319.19203-51-sashal@kernel.org> In-Reply-To: <20190806213319.19203-51-sashal@kernel.org> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-MC-Unique: Xw5AdrD2MRiS34lGOcsHNg-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)