[2/2] ipc: fix sparc64 ipc() wrapper

Matt bisected a sparc64 specific issue with semctl, shmctl and msgctl
to a commit from my y2038 series in linux-5.1, as I missed the custom
sys_ipc() wrapper that sparc64 uses in place of the generic version that
I patched.

The problem is that the sys_{sem,shm,msg}ctl() functions in the kernel
now do not allow being called with the IPC_64 flag any more, resulting
in a -EINVAL error when they don't recognize the command.

Instead, the correct way to do this now is to call the internal
ksys_old_{sem,shm,msg}ctl() functions to select the API version.

As we generally move towards these functions anyway, change all of
sparc_ipc() to consistently use those in place of the sys_*() versions,
and move the required ksys_*() declarations into linux/syscalls.h

Reported-by: Matt Turner <mattst88@gmail.com>
Fixes: 275f22148e87 ("ipc: rename old-style shmctl/semctl/msgctl syscalls")
Cc: stable@vger.kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
Hi Matt,

Can you check that this solves your problem?
---
 arch/sparc/kernel/sys_sparc_64.c | 30 +++++++++++++++---------------
 include/linux/syscalls.h         | 19 +++++++++++++++++++
 ipc/util.h                       | 25 ++-----------------------
 3 files changed, 36 insertions(+), 38 deletions(-)

On Thu, Sep 5, 2019 at 8:23 AM Arnd Bergmann <arnd@arndb.de> wrote:
>
> Matt bisected a sparc64 specific issue with semctl, shmctl and msgctl
> to a commit from my y2038 series in linux-5.1, as I missed the custom
> sys_ipc() wrapper that sparc64 uses in place of the generic version that
> I patched.
>
> The problem is that the sys_{sem,shm,msg}ctl() functions in the kernel
> now do not allow being called with the IPC_64 flag any more, resulting
> in a -EINVAL error when they don't recognize the command.
>
> Instead, the correct way to do this now is to call the internal
> ksys_old_{sem,shm,msg}ctl() functions to select the API version.
>
> As we generally move towards these functions anyway, change all of
> sparc_ipc() to consistently use those in place of the sys_*() versions,
> and move the required ksys_*() declarations into linux/syscalls.h
>
> Reported-by: Matt Turner <mattst88@gmail.com>
> Fixes: 275f22148e87 ("ipc: rename old-style shmctl/semctl/msgctl syscalls")
> Cc: stable@vger.kernel.org
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> Hi Matt,
>
> Can you check that this solves your problem?

Works great. Thank you Arnd!

Tested-by: Matt Turner <mattst88@gmail.com>

On Thu, Sep 5, 2019 at 9:39 PM Arnd Bergmann <arnd@arndb.de> wrote:
>
> Matt bisected a sparc64 specific issue with semctl, shmctl and msgctl
> to a commit from my y2038 series in linux-5.1, as I missed the custom
> sys_ipc() wrapper that sparc64 uses in place of the generic version that
> I patched.
>
> The problem is that the sys_{sem,shm,msg}ctl() functions in the kernel
> now do not allow being called with the IPC_64 flag any more, resulting
> in a -EINVAL error when they don't recognize the command.
>
> Instead, the correct way to do this now is to call the internal
> ksys_old_{sem,shm,msg}ctl() functions to select the API version.
>
> As we generally move towards these functions anyway, change all of
> sparc_ipc() to consistently use those in place of the sys_*() versions,
> and move the required ksys_*() declarations into linux/syscalls.h
>
> Reported-by: Matt Turner <mattst88@gmail.com>
> Fixes: 275f22148e87 ("ipc: rename old-style shmctl/semctl/msgctl syscalls")
> Cc: stable@vger.kernel.org
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>


Not Matt,

but this patch fixes util-linux.git ipcs test-suite (make check)
regression for me on current sparc64 git kernel (5.3.0-rc7), which was
broken somewhere in between 4.19 (debian unstable kernel) and 5.3-rcX.

Thanks!

PS: wanted to bisect kernel, but Matt did it first.

On Thu, Sep 5, 2019 at 5:24 PM Arnd Bergmann <arnd@arndb.de> wrote:

> diff --git a/arch/sparc/kernel/sys_sparc_64.c b/arch/sparc/kernel/sys_sparc_64.c
> index ccc88926bc00..5ad0494df367 100644
> --- a/arch/sparc/kernel/sys_sparc_64.c
> +++ b/arch/sparc/kernel/sys_sparc_64.c
> @@ -340,21 +340,21 @@ SYSCALL_DEFINE6(sparc_ipc, unsigned int, call, int, first, unsigned long, second
>         if (call <= SEMTIMEDOP) {
>                 switch (call) {
>                 case SEMOP:
> -                       err = sys_semtimedop(first, ptr,
> -                                            (unsigned int)second, NULL);
> +                       err = ksys_semtimedop(first, ptr,
> +                                             (unsigned int)second, NULL);
>                         goto out;

The zero-day bot found a link error in sparc64 allnoconfig:

   arch/sparc/kernel/sys_sparc_64.o: In function `__se_sys_sparc_ipc':
>> sys_sparc_64.c:(.text+0x724): undefined reference to `ksys_semtimedop'
>> sys_sparc_64.c:(.text+0x76c): undefined reference to `ksys_old_msgctl'
>> sys_sparc_64.c:(.text+0x7a8): undefined reference to `ksys_semget'
>> sys_sparc_64.c:(.text+0x7c8): undefined reference to `ksys_old_semctl'
>> sys_sparc_64.c:(.text+0x7e4): undefined reference to `ksys_msgsnd'
>> sys_sparc_64.c:(.text+0x7fc): undefined reference to `ksys_shmget'
>> sys_sparc_64.c:(.text+0x808): undefined reference to `ksys_shmdt'
   sys_sparc_64.c:(.text+0x828): undefined reference to `ksys_semtimedop'
>> sys_sparc_64.c:(.text+0x844): undefined reference to `ksys_old_shmctl'
>> sys_sparc_64.c:(.text+0x858): undefined reference to `ksys_msgget'
>> sys_sparc_64.c:(.text+0x86c): undefined reference to `ksys_msgrcv'

I've added this hunk to my patch and plan to send both fixes to Linus
in the next few days, after I get a positive report from the bot as well:

--- a/arch/sparc/kernel/sys_sparc_64.c
+++ b/arch/sparc/kernel/sys_sparc_64.c
@@ -336,6 +336,9 @@ SYSCALL_DEFINE6(sparc_ipc, unsigned int, call,
int, first, unsigned long, second
 {
        long err;

+       if (!IS_ENABLED(CONFIG_SYSVIPC))
+               return -ENOSYS;
+
        /* No need for backward compatibility. We can start fresh... */

        if (call <= SEMTIMEDOP) {
                switch (call) {