[PATCH 2/2] powerpc/ptrace: Fix setting 512B aligned breakpoints with PTRACE_SET_DEBUGREG

[Michael Neuling]

On Fri, 2018-05-18 at 22:56 +1000, Michael Ellerman wrote:
> Michael Neuling <mikey at neuling.org> writes:
> > In this change:
> >   e2a800beac powerpc/hw_brk: Fix off by one error when validating DAWR
> > region end
> > 
> > We fixed setting the DAWR end point to its max value via
> > PPC_PTRACE_SETHWDEBUG. Unfortunately we broke PTRACE_SET_DEBUGREG when
> > setting a 512 byte aligned breakpoint.
> > 
> > PTRACE_SET_DEBUGREG currently sets the length of the breakpoint to
> > zero (memset() in hw_breakpoint_init()).  This worked with
> > arch_validate_hwbkpt_settings() before the above patch was applied but
> > is now broken if the breakpoint is 512byte aligned.
> > 
> > This sets the length of the breakpoint to 8 bytes when using
> > PTRACE_SET_DEBUGREG.
> > 
> > Signed-off-by: Michael Neuling <mikey at neuling.org>
> > Cc: stable at vger.kernel.org # 3.10+
> 
> If this is "fixing" e2a800beac then I think v3.11 is right for the
> stable tag?
> 
> $ git describe --contains --long e2a800beaca1
> v3.11-rc1~94^2~4

You're right. I think read the output of gitk incorrectly.

Thanks.
Mikey