NVMe: Detect command IDs completing that are out of range

If the adapter completes a command ID that is outside the bounds of
the array, return CMD_CTX_INVALID instead of random data, and print a
message in the sync_completion handler (which is rapidly becoming the
misc completion handler :-)

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/block/nvme.c b/drivers/block/nvme.c
index 2dd09e7e142d..f4085d4fe0f2 100644
--- a/drivers/block/nvme.c
+++ b/drivers/block/nvme.c
@@ -170,12 +170,15 @@ enum {
 #define CMD_CTX_BASE            (POISON_POINTER_DELTA + sync_completion_id)
 #define CMD_CTX_CANCELLED       (0x2008 + CMD_CTX_BASE)
 #define CMD_CTX_COMPLETED       (0x2010 + CMD_CTX_BASE)
+#define CMD_CTX_INVALID         (0x2014 + CMD_CTX_BASE)
 
 static unsigned long free_cmdid(struct nvme_queue *nvmeq, int cmdid)
 {
         unsigned long data;
         unsigned offset = cmdid + BITS_TO_LONGS(nvmeq->q_depth);
 
+        if (cmdid > nvmeq->q_depth)
+                return CMD_CTX_INVALID;
         data = nvmeq->cmdid_data[offset];
         nvmeq->cmdid_data[offset] = CMD_CTX_COMPLETED;
         clear_bit(cmdid, nvmeq->cmdid_data);
@@ -411,6 +414,12 @@ static void sync_completion(struct nvme_queue *nvmeq, void *ctx,
                                 cqe->command_id, le16_to_cpup(&cqe->sq_id));
                 return;
         }
+        if (unlikely((unsigned long)cmdinfo == CMD_CTX_INVALID)) {
+                dev_warn(nvmeq->q_dmadev,
+                                "invalid id %d completed on queue %d\n",
+                                cqe->command_id, le16_to_cpup(&cqe->sq_id));
+                return;
+        }
         cmdinfo->result = le32_to_cpup(&cqe->result);
         cmdinfo->status = le16_to_cpup(&cqe->status) >> 1;
         wake_up_process(cmdinfo->task);