For CONFIG_CPUMASK_OFFSTACK=y kernel, explicit allocation of cpumask
variable on stack is not recommended since it can cause potential stack
overflow.
Instead, kernel code should always use *cpumask_var API(s) to allocate
cpumask var in config- neutral way, leaving allocation strategy to
CONFIG_CPUMASK_OFFSTACK.
Use *cpumask_var API(s) to address it.
Signed-off-by: Dawei Li <[email protected]>
---
drivers/perf/arm_dsu_pmu.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/drivers/perf/arm_dsu_pmu.c b/drivers/perf/arm_dsu_pmu.c
index bae3ca37f846..87efdca05807 100644
--- a/drivers/perf/arm_dsu_pmu.c
+++ b/drivers/perf/arm_dsu_pmu.c
@@ -230,13 +230,21 @@ static const struct attribute_group *dsu_pmu_attr_groups[] = {
NULL,
};
-static int dsu_pmu_get_online_cpu_any_but(struct dsu_pmu *dsu_pmu, int cpu)
+static unsigned int dsu_pmu_get_online_cpu_any_but(struct dsu_pmu *dsu_pmu, int cpu)
{
- struct cpumask online_supported;
+ cpumask_var_t online_supported;
+ unsigned int ret;
- cpumask_and(&online_supported,
- &dsu_pmu->associated_cpus, cpu_online_mask);
- return cpumask_any_but(&online_supported, cpu);
+ if (!alloc_cpumask_var(&online_supported, GFP_KERNEL))
+ return -ENOMEM;
+
+ cpumask_and(online_supported,
+ &dsu_pmu->associated_cpus, cpu_online_mask);
+ ret = cpumask_any_but(&online_supported, cpu);
+
+ free_cpumask_var(online_supported);
+
+ return ret;
}
static inline bool dsu_pmu_counter_valid(struct dsu_pmu *dsu_pmu, u32 idx)
--
2.27.0
Hi Dawei,
kernel test robot noticed the following build errors:
[auto build test ERROR on soc/for-next]
[also build test ERROR on linus/master v6.9-rc2 next-20240402]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Dawei-Li/perf-alibaba_uncore_drw-Avoid-explicit-cpumask-var-allocation-from-stack/20240402-192244
base: https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git for-next
patch link: https://lore.kernel.org/r/20240402105610.1695644-5-dawei.li%40shingroup.cn
patch subject: [PATCH 4/9] perf/arm_dsu: Avoid explicit cpumask var allocation from stack
config: arm64-defconfig (https://download.01.org/0day-ci/archive/20240403/[email protected]/config)
compiler: aarch64-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240403/[email protected]/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <[email protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
All errors (new ones prefixed by >>):
drivers/perf/arm_dsu_pmu.c: In function 'dsu_pmu_get_online_cpu_any_but':
>> drivers/perf/arm_dsu_pmu.c:243:31: error: passing argument 1 of 'cpumask_any_but' from incompatible pointer type [-Werror=incompatible-pointer-types]
243 | ret = cpumask_any_but(&online_supported, cpu);
| ^~~~~~~~~~~~~~~~~
| |
| struct cpumask (*)[1]
In file included from arch/arm64/include/asm/cpufeature.h:26,
from arch/arm64/include/asm/ptrace.h:11,
from arch/arm64/include/asm/irqflags.h:10,
from include/linux/irqflags.h:18,
from include/linux/spinlock.h:59,
from include/linux/mmzone.h:8,
from include/linux/gfp.h:7,
from include/linux/slab.h:16,
from include/linux/resource_ext.h:11,
from include/linux/acpi.h:13,
from drivers/perf/arm_dsu_pmu.c:14:
include/linux/cpumask.h:379:52: note: expected 'const struct cpumask *' but argument is of type 'struct cpumask (*)[1]'
379 | unsigned int cpumask_any_but(const struct cpumask *mask, unsigned int cpu)
| ~~~~~~~~~~~~~~~~~~~~~~^~~~
cc1: some warnings being treated as errors
vim +/cpumask_any_but +243 drivers/perf/arm_dsu_pmu.c
232
233 static unsigned int dsu_pmu_get_online_cpu_any_but(struct dsu_pmu *dsu_pmu, int cpu)
234 {
235 cpumask_var_t online_supported;
236 unsigned int ret;
237
238 if (!alloc_cpumask_var(&online_supported, GFP_KERNEL))
239 return -ENOMEM;
240
241 cpumask_and(online_supported,
242 &dsu_pmu->associated_cpus, cpu_online_mask);
> 243 ret = cpumask_any_but(&online_supported, cpu);
244
245 free_cpumask_var(online_supported);
246
247 return ret;
248 }
249
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
Hi Dawei,
kernel test robot noticed the following build errors:
[auto build test ERROR on soc/for-next]
[also build test ERROR on linus/master v6.9-rc2 next-20240402]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Dawei-Li/perf-alibaba_uncore_drw-Avoid-explicit-cpumask-var-allocation-from-stack/20240402-192244
base: https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git for-next
patch link: https://lore.kernel.org/r/20240402105610.1695644-5-dawei.li%40shingroup.cn
patch subject: [PATCH 4/9] perf/arm_dsu: Avoid explicit cpumask var allocation from stack
config: arm64-randconfig-001-20240403 (https://download.01.org/0day-ci/archive/20240403/[email protected]/config)
compiler: clang version 16.0.4 (https://github.com/llvm/llvm-project.git ae42196bc493ffe877a7e3dff8be32035dea4d07)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240403/[email protected]/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <[email protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
All errors (new ones prefixed by >>):
>> drivers/perf/arm_dsu_pmu.c:243:24: error: incompatible pointer types passing 'cpumask_var_t *' (aka 'struct cpumask **') to parameter of type 'const struct cpumask *'; remove & [-Werror,-Wincompatible-pointer-types]
ret = cpumask_any_but(&online_supported, cpu);
^~~~~~~~~~~~~~~~~
include/linux/cpumask.h:379:52: note: passing argument to parameter 'mask' here
unsigned int cpumask_any_but(const struct cpumask *mask, unsigned int cpu)
^
1 error generated.
vim +243 drivers/perf/arm_dsu_pmu.c
232
233 static unsigned int dsu_pmu_get_online_cpu_any_but(struct dsu_pmu *dsu_pmu, int cpu)
234 {
235 cpumask_var_t online_supported;
236 unsigned int ret;
237
238 if (!alloc_cpumask_var(&online_supported, GFP_KERNEL))
239 return -ENOMEM;
240
241 cpumask_and(online_supported,
242 &dsu_pmu->associated_cpus, cpu_online_mask);
> 243 ret = cpumask_any_but(&online_supported, cpu);
244
245 free_cpumask_var(online_supported);
246
247 return ret;
248 }
249
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki