On Mon, 10 Feb 2025 10:36:59 -0800 Zaid Alali <zaidal@xxxxxxxxxxxxxxxxxxxxxx> wrote: > This patch fixes the kernel test robot warning reported here: > https://lore.kernel.org/all/202410241620.oApALow5-lkp@xxxxxxxxx/ > > Signed-off-by: Zaid Alali <zaidal@xxxxxxxxxxxxxxxxxxxxxx> Hi Zaid, Why in the read direction use structures on the stack, but in the write direction kmalloc them? I think they could all just be stack variables as they are all pretty small. Jonathan > } > @@ -444,8 +453,10 @@ static int __einj_error_inject(u32 type, u32 flags, u64 param1, u64 param2, > return rc; > apei_exec_ctx_set_input(&ctx, type); > if (acpi5) { > - struct set_error_type_with_address *v5param = einj_param; > + struct set_error_type_with_address *v5param; > > + v5param = kmalloc(sizeof(*v5param), GFP_KERNEL); As below. Not sure why you can't just use the stack for this. It's not very big. > + memcpy_fromio(v5param, einj_param, sizeof(*v5param)); > v5param->type = type; > if (type & ACPI5_VENDOR_BIT) { > switch (vendor_flags) { > @@ -490,15 +501,21 @@ static int __einj_error_inject(u32 type, u32 flags, u64 param1, u64 param2, > break; > } > } > + memcpy_toio(einj_param, v5param, sizeof(*v5param)); > + kfree(v5param); > } else { > rc = apei_exec_run(&ctx, ACPI_EINJ_SET_ERROR_TYPE); > if (rc) > return rc; > if (einj_param) { > - struct einj_parameter *v4param = einj_param; > + struct einj_parameter *v4param; Why kmalloc rather than on stack as you did for the reads? > > + v4param = kmalloc(sizeof(*v4param), GFP_KERNEL); > + memcpy_fromio(v4param, einj_param, sizeof(*v4param)); > v4param->param1 = param1; > v4param->param2 = param2; > + memcpy_toio(einj_param, v4param, sizeof(*v4param)); > + kfree(v4param); > } > } > rc = apei_exec_run(&ctx, ACPI_EINJ_EXECUTE_OPERATION);
