| From: Michael Neuling <mikey@neuling.org> |
| Date: Thu, 17 May 2018 15:37:15 +1000 |
| Subject: powerpc/ptrace: Fix setting 512B aligned breakpoints with |
| PTRACE_SET_DEBUGREG |
| |
| 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") |
| Signed-off-by: Michael Neuling <mikey@neuling.org> |
| Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> |
| Signed-off-by: Ben Hutchings <ben@decadent.org.uk> |
| --- |
| arch/powerpc/kernel/ptrace.c | 1 + |
| 1 file changed, 1 insertion(+) |
| |
| --- a/arch/powerpc/kernel/ptrace.c |
| +++ b/arch/powerpc/kernel/ptrace.c |
| @@ -1011,6 +1011,7 @@ int ptrace_set_debugreg(struct task_stru |
| /* 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); |
| |