Re: [Qemu-devel] [PATCH] linux-user: fix __NR_semtimedop undeclared error

[Laurent Vivier]

On 23/05/2019 19:54, Laurent Vivier wrote:
> In current code, __NR_msgrcv and__NR_semtimedop are supposed to be
> defined if __NR_msgsnd is defined.
>
> But linux headers 5.2-rc1 for MIPS define __NR_msgsnd without defining
> __NR_semtimedop and it breaks the QEMU build.
>
> __NR_semtimedop is defined in asm-mips/unistd_n64.h and asm-mips/unistd_n32.h
> but not in asm-mips/unistd_o32.h.
>
> Commit d9cb4336159a ("linux headers: update against Linux 5.2-rc1") has
> updated asm-mips/unistd_o32.h and added __NR_msgsnd but not __NR_semtimedop.
> It introduces __NR_semtimedop_time64 instead.
>
> This patch fixes the problem by checking for each __NR_XXX symbol
> before defining the corresponding syscall.
>
> Fixes: d9cb4336159a ("linux headers: update against Linux 5.2-rc1")
> Reported-by: Philippe Mathieu-Daudé <address@hidden>
> Signed-off-by: Laurent Vivier <address@hidden>
> ---
>   linux-user/syscall.c | 24 ++++++++++++++++--------
>   1 file changed, 16 insertions(+), 8 deletions(-)

This only fixes the problem at build time, but the changes in the kernel 
headers introduce also a regression at execution time:

if the host kernel doesn't implement the syscall, the syscall fails 
(ENOSYS) whereas it was working before because it was using ipc() 
instead. I have this problem with a Fedora 28 on ppc64 
(5.0.16-100.fc28.ppc64) (LTP test msgctl07).

I'm preparing a fix.

Thanks,
Laurent