redonkable
/
alistair23-linux
1
0
Fork 0
Code Releases Activity

clk: qcom: rcg2: Don't crash if our parent can't be found; return an error 

[ Upstream commit 908b050114 ]

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: ac269395cd ("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>
5.4-rM2-2.2.x-imx-squashed
Douglas Anderson 2020-02-03 10:31:34 -08:00 committed by Greg Kroah-Hartman
parent 8d122cd0d2
commit dff5d0fc77
1 changed files with 3 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
drivers/clk/qcom/clk-rcg2.c
View File

@ -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) {