6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Gustavo A. R. Silva gustavoars@kernel.org
commit 6e4bf018bb040955da53dae9f8628ef8fcec2dbe upstream.
Some heap space is allocated for the flexible structure `struct clk_hw_onecell_data` and its flexible-array member `hws` through the composite structure `struct loongson2_clk_provider` in function `loongson2_clk_probe()`, as shown below:
289 struct loongson2_clk_provider *clp; ... 296 for (p = data; p->name; p++) 297 clks_num++; 298 299 clp = devm_kzalloc(dev, struct_size(clp, clk_data.hws, clks_num), 300 GFP_KERNEL);
Then some data is written into the flexible array:
350 clp->clk_data.hws[p->id] = hw;
This corrupts `clk_lock`, which is the spinlock variable immediately following the `clk_data` member in `struct loongson2_clk_provider`:
struct loongson2_clk_provider { void __iomem *base; struct device *dev; struct clk_hw_onecell_data clk_data; spinlock_t clk_lock; /* protect access to DIV registers */ };
The problem is that the flexible structure is currently placed in the middle of `struct loongson2_clk_provider` instead of at the end.
Fix this by moving `struct clk_hw_onecell_data clk_data;` to the end of `struct loongson2_clk_provider`. Also, add a code comment to help prevent this from happening again in case new members are added to the structure in the future.
This change also fixes the following -Wflex-array-member-not-at-end warning:
drivers/clk/clk-loongson2.c:32:36: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
Fixes: 9796ec0bd04b ("clk: clk-loongson2: Refactor driver for adding new platforms") Cc: stable@vger.kernel.org Signed-off-by: Gustavo A. R. Silva gustavoars@kernel.org Link: https://lore.kernel.org/r/ZzZ-cd_EFXs6qFaH@kspp Signed-off-by: Stephen Boyd sboyd@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/clk/clk-loongson2.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/clk/clk-loongson2.c +++ b/drivers/clk/clk-loongson2.c @@ -29,8 +29,10 @@ enum loongson2_clk_type { struct loongson2_clk_provider { void __iomem *base; struct device *dev; - struct clk_hw_onecell_data clk_data; spinlock_t clk_lock; /* protect access to DIV registers */ + + /* Must be last --ends in a flexible-array member. */ + struct clk_hw_onecell_data clk_data; };
struct loongson2_clk_data {