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

Michael Neuling [off-list ref] 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 <redacted>
Cc: stable@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

cheers