Re: [patch 06/12] rseq: Implement sys_rseq_slice_yield()

Thomas Gleixner
2025-09-09T12:23:40Z

On Tue, Sep 09 2025 at 15:22, K. Prateek Nayak wrote:
> On 9/9/2025 4:30 AM, Thomas Gleixner wrote:
>> /* restartable sequence */
>> COND_SYSCALL(rseq);
>> +COND_SYSCALL(rseq_sched_yield);
>
> I'm not sure if it is my toolchain but when I try to build a version
> with CONFIG_RSEQ_SLICE_EXTENSION disabled, I see:
>
> ld: vmlinux.o: in function `x64_sys_call':
> arch/x86/include/generated/asm/syscalls_64.h:471: undefined reference to `__x64_sys_rseq_slice_yield'
> ld: vmlinux.o: in function `ia32_sys_call':
> arch/x86/include/generated/asm/syscalls_32.h:471: undefined reference to `__ia32_sys_rseq_slice_yield'
> ld: vmlinux.o:(.rodata+0x12d0): undefined reference to `__x64_sys_rseq_slice_yield'
>
> I would have assumed the COND_SYSCALL() above would have stubbed this
> but that doesn't seem to be the case. Am I missing something?

Yes.

>> +COND_SYSCALL(rseq_sched_yield);

does not create a stub for rseq_slice_yield() obviously :)

/me looks for a brown paperbag.