Re: [PATCH] s390: fix build error for sys_call_table_emu

[Heiko Carstens <heiko.carstens@de.ibm.com>]

On Thu, Jun 18, 2020 at 07:03:20PM +0800, Xiaoming Ni wrote:
> Build error on s390:
> 	arch/s390/kernel/entry.o: in function `sys_call_table_emu':
> 	>> (.rodata+0x1288): undefined reference to `__s390_'
> 
> In commit ("All arch: remove system call sys_sysctl")
>  148  common	fdatasync		sys_fdatasync			sys_fdatasync
> -149  common	_sysctl			sys_sysctl			compat_sys_sysctl
> +149  common	_sysctl			sys_ni_syscall
>  150  common	mlock			sys_mlock			sys_mlock
> 
> After the patch is integrated, there is a format error in the generated
> arch/s390/include/generated/asm/syscall_table.h:
> 	SYSCALL(sys_fdatasync, sys_fdatasync)
> 	SYSCALL(sys_ni_syscall,) /* cause build error */
> 	SYSCALL(sys_mlock,sys_mlock)
> 
> There are holes in the system call number in
>  arch/s390/kernel/syscalls/syscall.tbl. When generating syscall_table.h,
> these hole numbers will be automatically filled with "NI_SYSCALL".
> Therefore, delete the number 149 to fix the current compilation failure.
>  Similarly, modify tools/perf/arch/s390/entry/syscalls/syscall.tbl.
> 
> Fixes: ("All arch: remove system call sys_sysctl")
> Fixes: https://lore.kernel.org/linuxppc-dev/20200616030734.87257-1-nixiaoming@huawei.com/
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
> ---
>  arch/s390/kernel/syscalls/syscall.tbl           | 1 -
>  tools/perf/arch/s390/entry/syscalls/syscall.tbl | 1 -
>  2 files changed, 2 deletions(-)
> 
> diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
> index f17aaf6fe5de..bcaf93994e3c 100644
> --- a/arch/s390/kernel/syscalls/syscall.tbl
> +++ b/arch/s390/kernel/syscalls/syscall.tbl
> @@ -138,7 +138,6 @@
>  146  common	writev			sys_writev			compat_sys_writev
>  147  common	getsid			sys_getsid			sys_getsid
>  148  common	fdatasync		sys_fdatasync			sys_fdatasync
> -149  common	_sysctl			sys_ni_syscall

This is not correct. It should be changed to:

   149  common	_sysctl			-				-

Otherwise the generated __NR__sysctl define will be lost from
unistd.h, which should not happen. Looking at the link above it
_looks_ like a similar mistake was done for arm64.

> diff --git a/tools/perf/arch/s390/entry/syscalls/syscall.tbl b/tools/perf/arch/s390/entry/syscalls/syscall.tbl
> index 0193f9b98753..eb77d0d01d8f 100644
> --- a/tools/perf/arch/s390/entry/syscalls/syscall.tbl
> +++ b/tools/perf/arch/s390/entry/syscalls/syscall.tbl
> @@ -138,7 +138,6 @@
>  146  common	writev			sys_writev			compat_sys_writev
>  147  common	getsid			sys_getsid			sys_getsid
>  148  common	fdatasync		sys_fdatasync			sys_fdatasync
> -149  common	_sysctl			sys_ni_syscall

Same here.