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authorDouglas Anderson <dianders@chromium.org>2020-02-03 21:31:34 +0300
committerStephen Boyd <sboyd@kernel.org>2020-02-04 10:04:02 +0300
commit908b050114d8fefdddc57ec9fbc213c3690e7f5f (patch)
tree08d32f4c7d1d2b31f48db60b71e739b416d45934 /drivers/clk
parent73cb3106e883ac03cc4f15b20d525e6bde650526 (diff)
downloadlinux-908b050114d8fefdddc57ec9fbc213c3690e7f5f.tar.xz
clk: qcom: rcg2: Don't crash if our parent can't be found; return an error
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>
Diffstat (limited to 'drivers/clk')
-rw-r--r--drivers/clk/qcom/clk-rcg2.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/clk/qcom/clk-rcg2.c b/drivers/clk/qcom/clk-rcg2.c
index 973ecf4f6bc5..357159fe85b5 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) {