riscv: Increase stack size under KASAN

KASAN requires more stack space because of compiler instrumentation.
Increase stack size as other arches do.
Signed-off-by: NDmitry Vyukov <dvyukov@google.com>
Reported-by: syzbot+0600986d88e2d4d7ebb8@syzkaller.appspotmail.com
Fixes: 8ad8b727 ("riscv: Add KASAN support")
Cc: stable@vger.kernel.org
Signed-off-by: NPalmer Dabbelt <palmer@rivosinc.com>

arch/riscv/include/asm/thread_info.h

@@ -11,11 +11,17 @@
 #include <asm/page.h>
 #include <linux/const.h>
 
+#ifdef CONFIG_KASAN
+#define KASAN_STACK_ORDER 1
+#else
+#define KASAN_STACK_ORDER 0
+#endif
+
 /* thread information allocation */
 #ifdef CONFIG_64BIT
-#define THREAD_SIZE_ORDER	(2)
+#define THREAD_SIZE_ORDER	(2 + KASAN_STACK_ORDER)
 #else
-#define THREAD_SIZE_ORDER	(1)
+#define THREAD_SIZE_ORDER	(1 + KASAN_STACK_ORDER)
 #endif
 #define THREAD_SIZE		(PAGE_SIZE << THREAD_SIZE_ORDER)