[IA64] mca_drv: Add minstate validation

MCA driver can cause panic if kernel gets a state info with no minstate.
This patch adds minstate validation before handling it.

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/arch/ia64/kernel/mca_drv.c b/arch/ia64/kernel/mca_drv.c
index 3492e3211a44..8fd93afa75a7 100644
--- a/arch/ia64/kernel/mca_drv.c
+++ b/arch/ia64/kernel/mca_drv.c
@@ -437,6 +437,9 @@ recover_from_read_error(slidx_table_t *slidx,
          *    the process not have any locks of kernel.
          */
 
+        /* Is minstate valid? */
+        if (!peidx_bottom(peidx) || !(peidx_bottom(peidx)->valid.minstate))
+                return 0;
         psr1 =(struct ia64_psr *)&(peidx_minstate_area(peidx)->pmsa_ipsr);
 
         /*