Re: [PATCH 6.7 000/707] 6.7.11-rc2 review

[Daniel Díaz]

Hello!

On Mon, 25 Mar 2024 at 12:14, Sami Tolvanen <samitolvanen@xxxxxxxxxx> wrote:
> On Mon, Mar 25, 2024 at 11:43:48AM -0600, Daniel Díaz wrote:
> > Hello!
> >
> > On 25/03/24 6:00 a. m., Sasha Levin wrote:
> > > This is the start of the stable review cycle for the 6.7.11 release.
> > > There are 707 patches in this series, all will be posted as a response
> > > to this one.  If anyone has any issues with these being applied, please
> > > let me know.
> > >
> > > Responses should be made by Wed Mar 27 12:00:02 PM UTC 2024.
> > > Anything received after that time might be too late.
> > >
> > > The whole patch series can be found in one patch at:
> > >          https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git/patch/?id=linux-6.7.y&id2=v6.7.10
> > > or in the git tree and branch at:
> > >          git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-6.7.y
> > > and the diffstat can be found below.
> > >
> > > Thanks,
> > > Sasha
> >
> > We see *lots* of new warnings in RISC-V with Clang 17. Here's one:
> >
> > -----8<-----
> >   /builds/linux/mm/oom_kill.c:1195:1: warning: unused function '___se_sys_process_mrelease' [-Wunused-function]
> >    1195 | SYSCALL_DEFINE2(process_mrelease, int, pidfd, unsigned int, flags)
> >         | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >   /builds/linux/include/linux/syscalls.h:221:36: note: expanded from macro 'SYSCALL_DEFINE2'
> >     221 | #define SYSCALL_DEFINE2(name, ...) SYSCALL_DEFINEx(2, _##name, __VA_ARGS__)
> >         |                                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >   /builds/linux/include/linux/syscalls.h:231:2: note: expanded from macro 'SYSCALL_DEFINEx'
> >     231 |         __SYSCALL_DEFINEx(x, sname, __VA_ARGS__)
> >         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >   /builds/linux/arch/riscv/include/asm/syscall_wrapper.h:81:2: note: expanded from macro '__SYSCALL_DEFINEx'
> >      81 |         __SYSCALL_SE_DEFINEx(x, sys, name, __VA_ARGS__)                         \
> >         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >   /builds/linux/arch/riscv/include/asm/syscall_wrapper.h:40:14: note: expanded from macro '__SYSCALL_SE_DEFINEx'
> >      40 |         static long ___se_##prefix##name(__MAP(x,__SC_LONG,__VA_ARGS__))
> >         |                     ^~~~~~~~~~~~~~~~~~~~
> >   <scratch space>:30:1: note: expanded from here
> >      30 | ___se_sys_process_mrelease
> >         | ^~~~~~~~~~~~~~~~~~~~~~~~~~
> >   1 warning generated.
> > ----->8-----
>
> Yup, I can reproduce this with ToT Clang. It looks like the alias
> isn't sufficient for Clang and we need to add an explicit __used
> attribute. Can you confirm if this patch fixes the issue for you?
>
> diff --git a/arch/riscv/include/asm/syscall_wrapper.h b/arch/riscv/include/asm/syscall_wrapper.h
> index 980094c2e976..ac80216549ff 100644
> --- a/arch/riscv/include/asm/syscall_wrapper.h
> +++ b/arch/riscv/include/asm/syscall_wrapper.h
> @@ -36,7 +36,8 @@ asmlinkage long __riscv_sys_ni_syscall(const struct pt_regs *);
>                                         ulong)                                          \
>                         __attribute__((alias(__stringify(___se_##prefix##name))));      \
>         __diag_pop();                                                                   \
> -       static long noinline ___se_##prefix##name(__MAP(x,__SC_LONG,__VA_ARGS__));      \
> +       static long noinline ___se_##prefix##name(__MAP(x,__SC_LONG,__VA_ARGS__))       \
> +                       __used;                                                         \
>         static long ___se_##prefix##name(__MAP(x,__SC_LONG,__VA_ARGS__))

It does: the hundreds of warnings are gone. Build-tested with Clang
17. Logs, configs, binaries, etc., here:

  https://tuxapi.tuxsuite.com/v1/groups/linaro/projects/daniel/builds/2eC43UtTjYk6loC9pNKT28SGmd5

Tested-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>

Thanks and greetings!

Daniel Díaz
daniel.diaz@xxxxxxxxxx