mainline build failure for x86_64 and arm64 with clang

[Sudip Mukherjee (Codethink)]

Hi All,

Yesterday I updated my clang to:
clang version 16.0.0 (https://github.com/llvm/llvm-project.git bcb1397bda667e75200ae0be9a65fd17dd0763d4)

And with that I see new build failures of mainline.

I am not copying all the errors but others look similar to these.
>From x86_64 almodconfig:

In file included from scripts/mod/devicetable-offsets.c:3:
In file included from ./include/linux/mod_devicetable.h:13:
In file included from ./include/linux/uuid.h:12:
In file included from ./include/linux/string.h:253:
./include/linux/fortify-string.h:159:10: error: ISO C does not allow indirection on operand of type 'void *' [-Werror,-Wvoid-ptr-dereference]
        q_len = strlen(q);
                ^~~~~~~~~

>From x86_64 defconfig:

In file included from arch/x86/kernel/asm-offsets.c:9:
In file included from ./include/linux/crypto.h:20:
In file included from ./include/linux/slab.h:15:
In file included from ./include/linux/gfp.h:7:
In file included from ./include/linux/mmzone.h:8:
In file included from ./include/linux/spinlock.h:55:
In file included from ./include/linux/preempt.h:78:
In file included from ./arch/x86/include/asm/preempt.h:7:
In file included from ./include/linux/thread_info.h:60:
In file included from ./arch/x86/include/asm/thread_info.h:53:
In file included from ./arch/x86/include/asm/cpufeature.h:5:
In file included from ./arch/x86/include/asm/processor.h:22:
In file included from ./arch/x86/include/asm/msr.h:11:
In file included from ./arch/x86/include/asm/cpumask.h:5:
In file included from ./include/linux/cpumask.h:12:
In file included from ./include/linux/bitmap.h:9:
./include/linux/find.h:119:31: error: ISO C does not allow indirection on operand of type 'void *' [-Werror,-Wvoid-ptr-dereference]
                unsigned long val = *addr & GENMASK(size - 1, 0);
                                            ^~~~~~~~~~~~~~~~~~~~
./include/linux/bits.h:38:3: note: expanded from macro 'GENMASK'
        (GENMASK_INPUT_CHECK(h, l) + __GENMASK(h, l))
         ^~~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/bits.h:25:3: note: expanded from macro 'GENMASK_INPUT_CHECK'
                __is_constexpr((l) > (h)), (l) > (h), 0)))
                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/const.h:12:25: note: expanded from macro '__is_constexpr'
        (sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8)))
                               ^
./include/linux/build_bug.h:16:62: note: expanded from macro 'BUILD_BUG_ON_ZERO'
#define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); })))


>From arm64 allmodconfig:

In file included from scripts/mod/devicetable-offsets.c:3:
In file included from ./include/linux/mod_devicetable.h:13:
In file included from ./include/linux/uuid.h:12:
In file included from ./include/linux/string.h:253:
./include/linux/fortify-string.h:159:10: error: ISO C does not allow indirection on operand of type 'void *' [-Werror,-Wvoid-ptr-dereference]
        q_len = strlen(q);
                ^~~~~~~~~
./include/linux/fortify-string.h:131:24: note: expanded from macro 'strlen'
        __builtin_choose_expr(__is_constexpr(__builtin_strlen(p)),      \
                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/const.h:12:25: note: expanded from macro '__is_constexpr'
        (sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8)))
                               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I dont know if its some regression introduced in clang, or really a kernel issue.

I will go back to my previous clang version (329b972d416a) for now untill I know more.

-- 
Regards
Sudip