From patchwork Thu Jan 30 21:12:17 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 11358689 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B1730139A for ; Thu, 30 Jan 2020 21:12:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9069F214DB for ; Thu, 30 Jan 2020 21:12:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="NQMw82GE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727515AbgA3VMu (ORCPT ); Thu, 30 Jan 2020 16:12:50 -0500 Received: from mail-pg1-f195.google.com ([209.85.215.195]:42187 "EHLO mail-pg1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727089AbgA3VMu (ORCPT ); Thu, 30 Jan 2020 16:12:50 -0500 Received: by mail-pg1-f195.google.com with SMTP id s64so2278721pgb.9 for ; Thu, 30 Jan 2020 13:12:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=qiYgMeeUC0YBpAKelC+4dn+CN5ICnSUf2MkjMCbgL5c=; b=NQMw82GEkZ6PCiwjiH4rDlQHZWp89OEeOFi1fTtGIJyi/seUYDg2GVNuf+3iQS0Fiu /eWZAkdKHkVeg51jDe0fQTGXbsqxftfBFdoE3DR4sZN3MTn3L6mbGeWlkrJj4jC+W2eK 2B8kfMWCHQ2xh4NPd/FxrnPp2i9YH3BXJyFbc= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=qiYgMeeUC0YBpAKelC+4dn+CN5ICnSUf2MkjMCbgL5c=; b=iAvCt+J5UrewaiFngkuHB+5g86nk88o4HApZ8R2b3lnrYgJAaKH2+NJ3tsA9VBxFPY CwbHvlwxEvwUbqCuHi3mTQjt4jlRAgxREcT5J96haG7UmAJpsIFK7Ls8hPNN6uezbWmF /IZg3Ea+rCVVBoIR8RjC0X9yPEsPhom+GVnnRL1bfslMQtfSVuIJbZM68rRteAtPCpN7 VfdoYA+6hQK9zHT/N8PJG/ia1/JicTTwvilEmBMwyvb+wXz7WKxNYzAMBAr131zIhnt1 jU7LGCL+fP7g/k7S/rfQ7NF3KjcDdtv5DqQUWBH2zEPSMTJRe7LIf0tt+pUoat3abXEg FOeQ== X-Gm-Message-State: APjAAAXodiXM53lQl0pmY9Qr5W1gptOh3yvcH/fSPafFd8c3yYWip9Yh pbzO0nF9EBCV6y8Imgy/G0orHA== X-Google-Smtp-Source: APXvYqxtcrlprtA94Pt11rgDOHvAhaLPmxrkPcj2drtGice8emH1/TtSR99Y/5dZQDkssXFxNGMyOQ== X-Received: by 2002:a65:4242:: with SMTP id d2mr6728403pgq.166.1580418769626; Thu, 30 Jan 2020 13:12:49 -0800 (PST) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:1:24fa:e766:52c9:e3b2]) by smtp.gmail.com with ESMTPSA id ci5sm4343871pjb.5.2020.01.30.13.12.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Jan 2020 13:12:49 -0800 (PST) From: Douglas Anderson To: Rob Herring , Andy Gross , Bjorn Andersson , Stephen Boyd Cc: Jeffrey Hugo , Taniya Das , jeffrey.l.hugo@gmail.com, linux-arm-msm@vger.kernel.org, harigovi@codeaurora.org, devicetree@vger.kernel.org, mka@chromium.org, kalyan_t@codeaurora.org, Mark Rutland , linux-clk@vger.kernel.org, hoegsberg@chromium.org, Douglas Anderson , Michael Turquette , linux-kernel@vger.kernel.org Subject: [PATCH v3 01/15] clk: qcom: rcg2: Don't crash if our parent can't be found; return an error Date: Thu, 30 Jan 2020 13:12:17 -0800 Message-Id: <20200130131220.v3.1.I7487325fe8e701a68a07d3be8a6a4b571eca9cfa@changeid> X-Mailer: git-send-email 2.25.0.341.g760bfbb309-goog In-Reply-To: <20200130211231.224656-1-dianders@chromium.org> References: <20200130211231.224656-1-dianders@chromium.org> MIME-Version: 1.0 Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org When I got my clock parenting slightly wrong I ended up with a crash that looked like this: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 ... pc : clk_hw_get_rate+0x14/0x44 ... Call trace: clk_hw_get_rate+0x14/0x44 _freq_tbl_determine_rate+0x94/0xfc clk_rcg2_determine_rate+0x2c/0x38 clk_core_determine_round_nolock+0x4c/0x88 clk_core_round_rate_nolock+0x6c/0xa8 clk_core_round_rate_nolock+0x9c/0xa8 clk_core_set_rate_nolock+0x70/0x180 clk_set_rate+0x3c/0x6c of_clk_set_defaults+0x254/0x360 platform_drv_probe+0x28/0xb0 really_probe+0x120/0x2dc driver_probe_device+0x64/0xfc device_driver_attach+0x4c/0x6c __driver_attach+0xac/0xc0 bus_for_each_dev+0x84/0xcc driver_attach+0x2c/0x38 bus_add_driver+0xfc/0x1d0 driver_register+0x64/0xf8 __platform_driver_register+0x4c/0x58 msm_drm_register+0x5c/0x60 ... It turned out that clk_hw_get_parent_by_index() was returning NULL and we weren't checking. Let's check it so that we don't crash. Fixes: ac269395cdd8 ("clk: qcom: Convert to clk_hw based provider APIs") Signed-off-by: Douglas Anderson Reviewed-by: Matthias Kaehlcke --- I haven't gone back and tried to reproduce this same crash on older kernels, but I'll put the blame on commit ac269395cdd8 ("clk: qcom: Convert to clk_hw based provider APIs"). Before that if we got a NULL parent back it was fine and dandy since a NULL "struct clk" is valid to use but a NULL "struct clk_hw" is not. Changes in v3: - Add Matthias tag. Changes in v2: - Patch ("clk: qcom: rcg2: Don't crash...") new for v2. drivers/clk/qcom/clk-rcg2.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/clk/qcom/clk-rcg2.c b/drivers/clk/qcom/clk-rcg2.c index da045b200def..9098001ac805 100644 --- a/drivers/clk/qcom/clk-rcg2.c +++ b/drivers/clk/qcom/clk-rcg2.c @@ -218,6 +218,9 @@ static int _freq_tbl_determine_rate(struct clk_hw *hw, const struct freq_tbl *f, clk_flags = clk_hw_get_flags(hw); p = clk_hw_get_parent_by_index(hw, index); + if (!p) + return -EINVAL; + if (clk_flags & CLK_SET_RATE_PARENT) { rate = f->freq; if (f->pre_div) {