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 CC3EAC6FA82 for ; Sat, 10 Sep 2022 21:20:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229881AbiIJVUZ (ORCPT ); Sat, 10 Sep 2022 17:20:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57490 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230070AbiIJVTh (ORCPT ); Sat, 10 Sep 2022 17:19:37 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 39A104BD1B; Sat, 10 Sep 2022 14:18:01 -0700 (PDT) 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 A58DF60C5F; Sat, 10 Sep 2022 21:17:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EB803C43141; Sat, 10 Sep 2022 21:17:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1662844678; bh=TNpz5TSPLIITY9+EhMX9wDc1LMTj+4DwgPahXg/iDtk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uOio4aSo2mcc2ez6ecBpkjg8ymF8MNA92+zkOo0A9gDGr64Ccu0XuR8D04IX7lcuY A0H3884wDKhWYP2RYKFP+6NQt8gPtL8diGVM5C8mo1u9H2x1DPgu8E2Jva576sw10T SWKNSv6Qidl2wQYWYzNhDZbuoJofrQO4Zq+Sm4ggQXPmd7dZN8+KUjNdN0GujqEHoA /1lT9dXYuIqWKUcGmzIXuhlY7CA6FTtX+vmVssgXfXbiRjaAdKwUvZMpRczHWbzuhw uJcmvyPAT6tSScQUL5h9cFXl3S21O+nBQjQPByfWEOkZ2uv5NhBjX1W20Une8x5P1z B6nGf5b90Ipsw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Rob Clark , Sasha Levin , robdclark@gmail.com, quic_abhinavk@quicinc.com, dmitry.baryshkov@linaro.org, airlied@linux.ie, daniel@ffwll.ch, linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org Subject: [PATCH AUTOSEL 5.15 03/21] drm/msm/rd: Fix FIFO-full deadlock Date: Sat, 10 Sep 2022 17:17:34 -0400 Message-Id: <20220910211752.70291-3-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220910211752.70291-1-sashal@kernel.org> References: <20220910211752.70291-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Rob Clark [ Upstream commit 174974d8463b77c2b4065e98513adb204e64de7d ] If the previous thing cat'ing $debugfs/rd left the FIFO full, then subsequent open could deadlock in rd_write() (because open is blocked, not giving a chance for read() to consume any data in the FIFO). Also it is generally a good idea to clear out old data from the FIFO. Signed-off-by: Rob Clark Patchwork: https://patchwork.freedesktop.org/patch/496706/ Link: https://lore.kernel.org/r/20220807160901.2353471-2-robdclark@gmail.com Signed-off-by: Sasha Levin --- drivers/gpu/drm/msm/msm_rd.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/msm/msm_rd.c b/drivers/gpu/drm/msm/msm_rd.c index b55398a34fa48..e3f0dd4a36792 100644 --- a/drivers/gpu/drm/msm/msm_rd.c +++ b/drivers/gpu/drm/msm/msm_rd.c @@ -191,6 +191,9 @@ static int rd_open(struct inode *inode, struct file *file) file->private_data = rd; rd->open = true; + /* Reset fifo to clear any previously unread data: */ + rd->fifo.head = rd->fifo.tail = 0; + /* the parsing tools need to know gpu-id to know which * register database to load. */ -- 2.35.1