Fail reads which return the flag value for a non-existent register

Also check for read success in get_runlist_iter().

1 files changed, 2 insertions, 0 deletions

diff --git a/runlist.c b/runlist.c
index 94be18e..f6a05ac 100644
--- a/runlist.c
+++ b/runlist.c
@@ -41,6 +41,8 @@ int get_runlist_iter(struct nvdebug_state *g, int rl_id, struct runlist_iter *rl
         // before because the GPU had simply gone to sleep and invalidated its
         // register state, so nvgpu_readl() was simply returning garbage.
         rl_info.raw = nvdebug_readl(g, NV_PFIFO_ENG_RUNLIST(rl_id));
+        if (rl_info.raw == -1)
+                return -EIO;
         runlist_iova = ((u64)rl_base.ptr) << 12;
         printk(KERN_INFO "[nvdebug] Runlist %d @ %llx in %s (config raw: %x)\n",
                rl_id, runlist_iova, target_to_text(rl_base.target), rl_base.raw);