Re: [PATCH v18 12/18] trace-cmd: Implement new option in trace.dat file: TRACECMD_OPTION_TIME_SHIFT

[Steven Rostedt <rostedt@goodmis.org>]

On Fri, 13 Dec 2019 17:30:23 +0200
"Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:

> @@ -2370,6 +2489,28 @@ static int handle_options(struct tracecmd_input *handle)
>  			offset = strtoll(buf, NULL, 0);
>  			handle->ts_offset += offset;
>  			break;
> +		case TRACECMD_OPTION_TIME_SHIFT:
> +			/*
> +			 * long long int (8 bytes) trace session ID
> +			 * int (4 bytes) count of timestamp offsets.
> +			 * long long array of size [count] of times,
> +			 *      when the offsets were calculated.
> +			 * long long array of size [count] of timestamp offsets.
> +			 */
> +			if (size < 12 || handle->flags & TRACECMD_FL_IGNORE_DATE)
> +				break;
> +			handle->host.trace_id = tep_read_number(handle->pevent,
> +								buf, 8);
> +			handle->host.ts_samples_count = tep_read_number(handle->pevent,
> +									buf + 8, 4);
> +			samples_size = (8 * handle->host.ts_samples_count);
> +			if (size != (12 + (2 * samples_size)))
> +				break;
> +			handle->host.ts_samples = malloc(2 * samples_size);
> +			if (!handle->host.ts_samples)
> +				return -ENOMEM;
> +			tsync_offset_load(handle, buf + 12);
> +			break;
>  		case TRACECMD_OPTION_CPUSTAT:
>  			buf[size-1] = '\n';
>  			cpustats = realloc(cpustats, cpustats_size + size + 1);
> @@ -3078,6 +3219,8 @@ void tracecmd_close(struct tracecmd_input *handle)
>  	trace_pid_map_free(handle->pid_maps);
>  	handle->pid_maps = NULL;
>  
> +	trace_tsync_offset_free(&handle->host);

You need to add in tracecmd_buffer_instance_handle() something like:

	memset(&new_handle->host, 0, sizeof(new_handle->host));

or make a copy of it. Because if the host created sub buffers along
with the top level, you get multiple frees on the host.ts_samples, as
the new_handle will have a pointer to the original handle.

This is the same bug fixed by ca4b997b6505df3ce for trace_clock.

-- Steve


> +
>  	if (handle->flags & TRACECMD_FL_BUFFER_INSTANCE)
>  		tracecmd_close(handle->parent);
>  	else {