[media] coda: fix timestamp list handling

Lock modification of the timestamp list with bitstream_mutex and do not
try to remove a timestamp element if the list is empty. This can happen
if the userspace feeds us garbage or multiple encoded frames in a single
buffer.

Signed-off-by: Michael Olbrich <m.olbrich@pengutronix.de>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Kamil Debski <k.debski@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

2 files changed, 21 insertions, 9 deletions

diff --git a/drivers/media/platform/coda/coda-bit.c b/drivers/media/platform/coda/coda-bit.c
index 529cc3e8acb0..18fa369d204d 100644
--- a/drivers/media/platform/coda/coda-bit.c
+++ b/drivers/media/platform/coda/coda-bit.c
@@ -1699,18 +1699,28 @@ static void coda_finish_decode(struct coda_ctx *ctx)
                 v4l2_err(&dev->v4l2_dev,
                          "decoded frame index out of range: %d\n", decoded_idx);
         } else {
-                ts = list_first_entry(&ctx->timestamp_list,
-                                      struct coda_timestamp, list);
-                list_del(&ts->list);
                 val = coda_read(dev, CODA_RET_DEC_PIC_FRAME_NUM) - 1;
                 val -= ctx->sequence_offset;
-                if (val != (ts->sequence & 0xffff)) {
-                        v4l2_err(&dev->v4l2_dev,
-                                 "sequence number mismatch (%d(%d) != %d)\n",
-                                 val, ctx->sequence_offset, ts->sequence);
+                mutex_lock(&ctx->bitstream_mutex);
+                if (!list_empty(&ctx->timestamp_list)) {
+                        ts = list_first_entry(&ctx->timestamp_list,
+                                              struct coda_timestamp, list);
+                        list_del(&ts->list);
+                        if (val != (ts->sequence & 0xffff)) {
+                                v4l2_err(&dev->v4l2_dev,
+                                         "sequence number mismatch (%d(%d) != %d)\n",
+                                         val, ctx->sequence_offset,
+                                         ts->sequence);
+                        }
+                        ctx->frame_timestamps[decoded_idx] = *ts;
+                        kfree(ts);
+                } else {
+                        v4l2_err(&dev->v4l2_dev, "empty timestamp list!\n");
+                        memset(&ctx->frame_timestamps[decoded_idx], 0,
+                               sizeof(struct coda_timestamp));
+                        ctx->frame_timestamps[decoded_idx].sequence = val;
                 }
-                ctx->frame_timestamps[decoded_idx] = *ts;
-                kfree(ts);
+                mutex_unlock(&ctx->bitstream_mutex);
 
                 val = coda_read(dev, CODA_RET_DEC_PIC_TYPE) & 0x7;
                 if (val == 0)
diff --git a/drivers/media/platform/coda/coda-common.c b/drivers/media/platform/coda/coda-common.c
index 0f8a2c970405..e84b32088fc0 100644
--- a/drivers/media/platform/coda/coda-common.c
+++ b/drivers/media/platform/coda/coda-common.c
@@ -1116,12 +1116,14 @@ static void coda_stop_streaming(struct vb2_queue *q)
         if (!ctx->streamon_out && !ctx->streamon_cap) {
                 struct coda_timestamp *ts;
 
+                mutex_lock(&ctx->bitstream_mutex);
                 while (!list_empty(&ctx->timestamp_list)) {
                         ts = list_first_entry(&ctx->timestamp_list,
                                               struct coda_timestamp, list);
                         list_del(&ts->list);
                         kfree(ts);
                 }
+                mutex_unlock(&ctx->bitstream_mutex);
                 kfifo_init(&ctx->bitstream_fifo,
                         ctx->bitstream.vaddr, ctx->bitstream.size);
                 ctx->runcounter = 0;