powerpc/tm: Fix null pointer deference in flush_hash_page

Make sure that current->thread.reg exists before we deference it in
flush_hash_page.

Signed-off-by: Michael Neuling <[email protected]>
Reported-by: John J Miller <[email protected]>
Cc: <[email protected]>
Signed-off-by: Benjamin Herrenschmidt <[email protected]>

diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 3e4c4ed19335d6bd9fc6393c0663cad5bf05c1f7..88ac0eeaadde69bfeceb82d44527754638ed351b 100644 (file)
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -1230,6 +1230,7 @@ void flush_hash_page(unsigned long vpn, real_pte_t pte, int psize, int ssize,
         * unmapping it first, it may see the speculated version.
         */
        if (local && cpu_has_feature(CPU_FTR_TM) &&
+           current->thread.regs &&
            MSR_TM_ACTIVE(current->thread.regs->msr)) {
                tm_enable();
                tm_abort(TM_CAUSE_TLBI);