powerpc/tm: Fix saving of TM SPRs in core dump

Currently flush_tmregs_to_thread() does not save the TM SPRs (TFHAR,
TFIAR, TEXASR) to the thread struct, unless the process is currently
inside a suspended transaction.

If the process is core dumping, and the TM SPRs have changed since the
last time the process was context switched, then we will save stale
values of the TM SPRs to the core dump.

Fix it by saving the live register state to the thread struct in that
case.

Fixes: 08e1c01d6aed ("powerpc/ptrace: Enable support for TM SPR state")
Cc: stable@vger.kernel.org # v4.8+
Signed-off-by: Gustavo Romero <gromero@linux.vnet.ibm.com>
Reviewed-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index 925a4ef9055932174b4dc5a8f0424b330149132b..660ed39e9c9a59fc3b7087362787502a41ba50fd 100644 (file)
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -127,12 +127,19 @@ static void flush_tmregs_to_thread(struct task_struct *tsk)
         * If task is not current, it will have been flushed already to
         * it's thread_struct during __switch_to().
         *
-        * A reclaim flushes ALL the state.
+        * A reclaim flushes ALL the state or if not in TM save TM SPRs
+        * in the appropriate thread structures from live.
         */
 
-       if (tsk == current && MSR_TM_SUSPENDED(mfmsr()))
-               tm_reclaim_current(TM_CAUSE_SIGNAL);
+       if (tsk != current)
+               return;
 
+       if (MSR_TM_SUSPENDED(mfmsr())) {
+               tm_reclaim_current(TM_CAUSE_SIGNAL);
+       } else {
+               tm_enable();
+               tm_save_sprs(&(tsk->thread));
+       }
 }
 #else
 static inline void flush_tmregs_to_thread(struct task_struct *tsk) { }