ctf_close_trace was being called twice when calling bt_context_remove_trace thus
causing free() to be called on an invalid pointer.

Calling bt_context_remove_trace() would call ctf_close_trace() once via the
close_handle callback registered on the ctf format struct and a second call 
would
take place from bt_trace_handle_destroy() which is registered as the
value_destroy_func on the trace_handles hash table of the current context.

The first explicit call to handle->format->close_trace is unnecessary.

The crash is reproducible by invoking the tests-python.py script.

Signed-off-by: Jérémie Galarneau <[email protected]>
---
 lib/context.c      | 8 +-------
 lib/trace-handle.c | 5 ++++-
 2 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/lib/context.c b/lib/context.c
index 5516e49..05fb994 100644
--- a/lib/context.c
+++ b/lib/context.c
@@ -156,7 +156,6 @@ end:
 int bt_context_remove_trace(struct bt_context *ctx, int handle_id)
 {
        struct bt_trace_handle *handle;
-       int ret;
 
        if (!ctx)
                return -EINVAL;
@@ -168,12 +167,7 @@ int bt_context_remove_trace(struct bt_context *ctx, int 
handle_id)
 
        /* Remove from containers */
        trace_collection_remove(ctx->tc, handle->td);
-       /* Close the trace */
-       ret = handle->format->close_trace(handle->td);
-       if (ret) {
-               fprintf(stderr, "Error in close_trace callback\n");
-               return ret;
-       }
+
        /* Remove and free the handle */
        g_hash_table_remove(ctx->trace_handles,
                        (gpointer) (unsigned long) handle_id);
diff --git a/lib/trace-handle.c b/lib/trace-handle.c
index 0da565b..17a6e0d 100644
--- a/lib/trace-handle.c
+++ b/lib/trace-handle.c
@@ -49,7 +49,10 @@ struct bt_trace_handle *bt_trace_handle_create(struct 
bt_context *ctx)
 
 void bt_trace_handle_destroy(struct bt_trace_handle *th)
 {
-       th->format->close_trace(th->td);
+       if (th->format->close_trace(th->td)) {
+               fprintf(stderr, "Error in close_trace callback\n");
+       }
+
        g_free(th);
 }
 
-- 
1.8.1.1


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