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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Douglas Anderson <dianders@chromium.org>,
	Matthias Kaehlcke <mka@chromium.org>,
	Stephen Boyd <sboyd@kernel.org>, Sasha Levin <sashal@kernel.org>,
	linux-arm-msm@vger.kernel.org, linux-clk@vger.kernel.org
Subject: [PATCH AUTOSEL 5.5 130/542] clk: qcom: rcg2: Don't crash if our parent can't be found; return an error
Date: Fri, 14 Feb 2020 10:42:02 -0500
Message-ID: <20200214154854.6746-130-sashal@kernel.org> (raw)
In-Reply-To: <20200214154854.6746-1-sashal@kernel.org>

From: Douglas Anderson <dianders@chromium.org>

[ Upstream commit 908b050114d8fefdddc57ec9fbc213c3690e7f5f ]

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>
Link: https://lkml.kernel.org/r/20200203103049.v4.1.I7487325fe8e701a68a07d3be8a6a4b571eca9cfa@changeid
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 5e0f7d8f168dd..cecdb07ce13ba 100644
--- a/drivers/clk/qcom/clk-rcg2.c
+++ b/drivers/clk/qcom/clk-rcg2.c
@@ -217,6 +217,9 @@ 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) {
-- 
2.20.1


  parent reply index

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200214154854.6746-1-sashal@kernel.org>
2020-02-14 15:40 ` [PATCH AUTOSEL 5.5 020/542] clk: meson: g12a: fix missing uart2 in regmap table Sasha Levin
2020-02-14 15:40 ` [PATCH AUTOSEL 5.5 021/542] clk: meson: pll: Fix by 0 division in __pll_params_to_rate() Sasha Levin
2020-02-14 15:40 ` [PATCH AUTOSEL 5.5 047/542] clk: at91: sam9x60: fix programmable clock prescaler Sasha Levin
2020-02-14 15:40 ` [PATCH AUTOSEL 5.5 049/542] clk: meson: meson8b: make the CCF use the glitch-free mali mux Sasha Levin
2020-02-14 15:41 ` [PATCH AUTOSEL 5.5 085/542] clk: ti: dra7: fix parent for gmac_clkctrl Sasha Levin
2020-02-14 15:42 ` [PATCH AUTOSEL 5.5 129/542] clk: qcom: Don't overwrite 'cfg' in clk_rcg2_dfs_populate_freq() Sasha Levin
2020-02-14 15:42 ` Sasha Levin [this message]
2020-02-14 15:43 ` [PATCH AUTOSEL 5.5 196/542] clk: imx: Add correct failure handling for clk based helpers Sasha Levin
2020-02-14 15:43 ` [PATCH AUTOSEL 5.5 236/542] clk: qcom: smd: Add missing bimc clock Sasha Levin
2020-02-14 15:43 ` [PATCH AUTOSEL 5.5 245/542] clk: renesas: rcar-gen3: Allow changing the RPC[D2] clocks Sasha Levin
2020-02-14 15:44 ` [PATCH AUTOSEL 5.5 257/542] clk: qcom: Add missing msm8998 gcc_bimc_gfx_clk Sasha Levin
2020-02-14 15:44 ` [PATCH AUTOSEL 5.5 258/542] clk: actually call the clock init before any other callback of the clock Sasha Levin
2020-02-14 15:44 ` [PATCH AUTOSEL 5.5 260/542] clk: bm1800: Remove set but not used variable 'fref' Sasha Levin
2020-02-14 15:44 ` [PATCH AUTOSEL 5.5 279/542] clk: sunxi-ng: add mux and pll notifiers for A64 CPU clock Sasha Levin
2020-02-14 15:44 ` [PATCH AUTOSEL 5.5 281/542] clk: Use parent node pointer during registration if necessary Sasha Levin
2020-02-14 15:44 ` [PATCH AUTOSEL 5.5 282/542] clk: uniphier: Add SCSSI clock gate for each channel Sasha Levin

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