From: Dennis Zhou Date: Sun, 14 Feb 2021 17:16:33 +0000 (+0000) Subject: percpu: fix clang modpost section mismatch X-Git-Tag: accepted/tizen/unified/20230118.172025~7766^2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=258e0815e2b1706e87c0d874211097aa8a7aa52f;p=platform%2Fkernel%2Flinux-rpi.git percpu: fix clang modpost section mismatch pcpu_build_alloc_info() is an __init function that makes a call to cpumask_clear_cpu(). With CONFIG_GCOV_PROFILE_ALL enabled, the inline heuristics are modified and such cpumask_clear_cpu() which is marked inline doesn't get inlined. Because it works on mask in __initdata, modpost throws a section mismatch error. Arnd sent a patch with the flatten attribute as an alternative [2]. I've added it to compiler_attributes.h. modpost complaint: WARNING: modpost: vmlinux.o(.text+0x735425): Section mismatch in reference from the function cpumask_clear_cpu() to the variable .init.data:pcpu_build_alloc_info.mask The function cpumask_clear_cpu() references the variable __initdata pcpu_build_alloc_info.mask. This is often because cpumask_clear_cpu lacks a __initdata annotation or the annotation of pcpu_build_alloc_info.mask is wrong. clang output: mm/percpu.c:2724:5: remark: cpumask_clear_cpu not inlined into pcpu_build_alloc_info because too costly to inline (cost=725, threshold=325) [-Rpass-missed=inline] [1] https://lore.kernel.org/linux-mm/202012220454.9F6Bkz9q-lkp@intel.com/ [2] https://lore.kernel.org/lkml/CAK8P3a2ZWfNeXKSm8K_SUhhwkor17jFo3xApLXjzfPqX0eUDUA@mail.gmail.com/ Reported-by: kernel test robot Cc: Arnd Bergmann Cc: Nick Desaulniers Signed-off-by: Dennis Zhou --- diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h index ea5e04e..c043b8d 100644 --- a/include/linux/compiler_attributes.h +++ b/include/linux/compiler_attributes.h @@ -211,6 +211,12 @@ #endif /* + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#Common-Function-Attributes + * clang: https://clang.llvm.org/docs/AttributeReference.html#flatten + */ +# define __flatten __attribute__((flatten)) + +/* * Note the missing underscores. * * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-noinline-function-attribute diff --git a/mm/percpu.c b/mm/percpu.c index 80f8f88..6596a0a 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -2663,7 +2663,7 @@ early_param("percpu_alloc", percpu_alloc_setup); * On success, pointer to the new allocation_info is returned. On * failure, ERR_PTR value is returned. */ -static struct pcpu_alloc_info * __init pcpu_build_alloc_info( +static struct pcpu_alloc_info * __init __flatten pcpu_build_alloc_info( size_t reserved_size, size_t dyn_size, size_t atom_size, pcpu_fc_cpu_distance_fn_t cpu_distance_fn)