4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Michael Neuling <mikey@xxxxxxxxxxx>
commit 4f7c06e26ec9cf7fe9f0c54dc90079b6a4f4b2c3 upstream.
In commit e2a800beaca1 ("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.
Fixes: e2a800beaca1 ("powerpc/hw_brk: Fix off by one error when validating DAWR region end")
Cc: stable@xxxxxxxxxxxxxxx # v3.11+
Signed-off-by: Michael Neuling <mikey@xxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/kernel/ptrace.c | 1 +
1 file changed, 1 insertion(+)
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -2380,6 +2380,7 @@ static int ptrace_set_debugreg(struct ta
/* Create a new breakpoint request if one doesn't exist already */
hw_breakpoint_init(&attr);
attr.bp_addr = hw_brk.address;
+ attr.bp_len = 8;
arch_bp_generic_fields(hw_brk.type,
&attr.bp_type);
