Fix: kernel consumer: issue put_subbuf on error

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>

diff --git a/src/common/kernel-consumer/kernel-consumer.c b/src/common/kernel-consumer/kernel-consumer.c
index cca522dadd5a3210fd5ef79d5496e13eeedddfbc..e5595a1c3c106973bbbd285997612b98d422bca0 100644 (file)
--- a/src/common/kernel-consumer/kernel-consumer.c
+++ b/src/common/kernel-consumer/kernel-consumer.c
@@ -1084,6 +1084,17 @@ ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
        err = kernctl_get_padded_subbuf_size(infd, &len);
        if (err != 0) {
                perror("Getting sub-buffer len failed.");
+               err = kernctl_put_subbuf(infd);
+               if (err != 0) {
+                       if (errno == EFAULT) {
+                               perror("Error in unreserving sub buffer\n");
+                       } else if (errno == EIO) {
+                               /* Should never happen with newer LTTng versions */
+                               perror("Reader has been pushed by the writer, last sub-buffer corrupted.");
+                       }
+                       ret = -errno;
+                       goto end;
+               }
                ret = -errno;
                goto end;
        }
@@ -1091,6 +1102,17 @@ ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
        if (!stream->metadata_flag) {
                ret = get_index_values(&index, infd);
                if (ret < 0) {
+                       err = kernctl_put_subbuf(infd);
+                       if (err != 0) {
+                               if (errno == EFAULT) {
+                                       perror("Error in unreserving sub buffer\n");
+                               } else if (errno == EIO) {
+                                       /* Should never happen with newer LTTng versions */
+                                       perror("Reader has been pushed by the writer, last sub-buffer corrupted.");
+                               }
+                               ret = -errno;
+                               goto end;
+                       }
                        goto end;
                }
        } else {
@@ -1129,6 +1151,17 @@ ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
                err = kernctl_get_subbuf_size(infd, &subbuf_size);
                if (err != 0) {
                        perror("Getting sub-buffer len failed.");
+                       err = kernctl_put_subbuf(infd);
+                       if (err != 0) {
+                               if (errno == EFAULT) {
+                                       perror("Error in unreserving sub buffer\n");
+                               } else if (errno == EIO) {
+                                       /* Should never happen with newer LTTng versions */
+                                       perror("Reader has been pushed by the writer, last sub-buffer corrupted.");
+                               }
+                               ret = -errno;
+                               goto end;
+                       }
                        ret = -errno;
                        goto end;
                }