On Mon, Dec 03, 2018 at 06:18:23AM +0300, Dmitry V. Levin wrote:
> From: Elvira Khabirova <lineprinter@altlinux.org>
> 
> Arch code should use tracehook_*() helpers, as documented
> in include/linux/tracehook.h,
> ptrace_report_syscall() is not expected to be used outside that file.
> 
> Co-authored-by: Dmitry V. Levin <ldv@altlinux.org>
> Fixes: 5521eb4bca2d ("powerpc/ptrace: Add support for PTRACE_SYSEMU")
> Signed-off-by: Elvira Khabirova <lineprinter@altlinux.org>
> Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
> ---
> v4: rewritten to call tracehook_report_syscall_entry() once, compile-tested
> v3: add a descriptive comment
> v2: explicitly ignore tracehook_report_syscall_entry() return code
> 
>  arch/powerpc/kernel/ptrace.c | 54 +++++++++++++++++++++++-------------
>  1 file changed, 35 insertions(+), 19 deletions(-)

Sorry, this patch does not work, please ignore it.
However, the bug blocks PTRACE_GET_SYSCALL_INFO, so please fix it.

I'm going to use
	if (tracehook_report_syscall_entry(regs))
		return -1;
	return -1;
in the series until you have a better fix.


-- 
ldv