From: Douglas Anderson <dianders@chromium.org> To: Rob Herring <robh@kernel.org>, Andy Gross <agross@kernel.org>, Bjorn Andersson <bjorn.andersson@linaro.org>, Stephen Boyd <sboyd@kernel.org> Cc: Jeffrey Hugo <jhugo@codeaurora.org>, Taniya Das <tdas@codeaurora.org>, 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 <mark.rutland@arm.com>, linux-clk@vger.kernel.org, hoegsberg@chromium.org, Douglas Anderson <dianders@chromium.org>, Michael Turquette <mturquette@baylibre.com>, linux-kernel@vger.kernel.org Subject: [PATCH v4 01/15] clk: qcom: rcg2: Don't crash if our parent can't be found; return an error Date: Mon, 3 Feb 2020 10:31:34 -0800 Message-ID: <20200203103049.v4.1.I7487325fe8e701a68a07d3be8a6a4b571eca9cfa@changeid> (raw) In-Reply-To: <20200203183149.73842-1-dianders@chromium.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 <dianders@chromium.org> Reviewed-by: Matthias Kaehlcke <mka@chromium.org> --- 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 v4: None 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) { -- 2.25.0.341.g760bfbb309-goog
next prev parent reply index Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-02-03 18:31 [PATCH v4 00/15] clk: qcom: Fix parenting for dispcc/gpucc/videocc Douglas Anderson 2020-02-03 18:31 ` Douglas Anderson [this message] 2020-02-04 17:47 ` [PATCH v4 01/15] clk: qcom: rcg2: Don't crash if our parent can't be found; return an error Stephen Boyd 2020-02-03 18:31 ` [PATCH v4 02/15] dt-bindings: clock: Fix qcom,dispcc bindings for sdm845/sc7180 Douglas Anderson 2020-02-04 17:47 ` Stephen Boyd 2020-02-03 18:31 ` [PATCH v4 03/15] arm64: dts: qcom: sdm845: Add the missing clocks on the dispcc Douglas Anderson 2020-02-03 18:31 ` [PATCH v4 04/15] clk: qcom: Get rid of fallback global names for dispcc-sc7180 Douglas Anderson 2020-02-04 17:47 ` Stephen Boyd 2020-02-03 18:31 ` [PATCH v4 05/15] clk: qcom: Get rid of the test clock " Douglas Anderson 2020-02-04 17:47 ` Stephen Boyd 2020-02-03 18:31 ` [PATCH v4 06/15] clk: qcom: Use ARRAY_SIZE in dispcc-sc7180 for parent clocks Douglas Anderson 2020-02-04 17:48 ` Stephen Boyd 2020-02-03 18:31 ` [PATCH v4 07/15] dt-bindings: clock: Fix qcom,gpucc bindings for sdm845/sc7180/msm8998 Douglas Anderson 2020-02-04 17:48 ` Stephen Boyd 2020-02-03 18:31 ` [PATCH v4 08/15] arm64: dts: qcom: sdm845: Add missing clocks / fix names on the gpucc Douglas Anderson 2020-02-03 18:31 ` [PATCH v4 09/15] clk: qcom: Get rid of the test clock for gpucc-sc7180 Douglas Anderson 2020-02-04 17:48 ` Stephen Boyd 2020-02-03 18:31 ` [PATCH v4 10/15] clk: qcom: Use ARRAY_SIZE in gpucc-sc7180 for parent clocks Douglas Anderson 2020-02-04 17:48 ` Stephen Boyd 2020-02-03 18:31 ` [PATCH v4 11/15] dt-bindings: clock: Cleanup qcom,videocc bindings for sdm845/sc7180 Douglas Anderson 2020-02-04 17:48 ` Stephen Boyd 2020-02-04 20:49 ` Doug Anderson 2020-02-03 18:31 ` [PATCH v4 12/15] clk: qcom: Get rid of the test clock for videocc-sc7180 Douglas Anderson 2020-02-04 17:49 ` Stephen Boyd 2020-02-03 18:31 ` [PATCH v4 13/15] clk: qcom: Use ARRAY_SIZE in videocc-sc7180 for parent clocks Douglas Anderson 2020-02-04 17:49 ` Stephen Boyd 2020-02-03 18:31 ` [PATCH v4 14/15] arm64: dts: qcom: sdm845: Add the missing clock on the videocc Douglas Anderson 2020-02-03 18:31 ` [PATCH v4 15/15] arm64: dts: sc7180: Add clock controller nodes Douglas Anderson 2020-02-03 19:30 ` [PATCH v4 00/15] clk: qcom: Fix parenting for dispcc/gpucc/videocc Stephen Boyd 2020-02-03 19:41 ` Doug Anderson 2020-02-03 20:04 ` Bjorn Andersson 2020-02-03 20:48 ` Doug Anderson 2020-02-03 23:17 ` Bjorn Andersson
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