[ltt-dev] [PATCH] LTTNG: hold markers_mutex during marker section iteration

[mathieu.desnoyers@polymtl.ca (Mathieu Desnoyers)]

* Gui Jianfeng (guijianfeng at cn.fujitsu.com) wrote:
> Hold the markers_mutex during marker section iteration.
> 

Will merge, thanks !

Mathieu

> Signed-off-by: Gui Jianfeng <guijianfeng at cn.fujitsu.com>
> ---
>  kernel/marker.c         |    2 ++
>  ltt/ltt-trace-control.c |   12 ++++++++++++
>  2 files changed, 14 insertions(+), 0 deletions(-)
> 
> diff --git a/kernel/marker.c b/kernel/marker.c
> index 7d11393..93ffa8e 100644
> --- a/kernel/marker.c
> +++ b/kernel/marker.c
> @@ -44,11 +44,13 @@ void lock_markers(void)
>  {
>  	mutex_lock(&markers_mutex);
>  }
> +EXPORT_SYMBOL_GPL(lock_markers);
>  
>  void unlock_markers(void)
>  {
>  	mutex_unlock(&markers_mutex);
>  }
> +EXPORT_SYMBOL_GPL(unlock_markers);
>  
>  /*
>   * Marker hash table, containing the active markers.
> diff --git a/ltt/ltt-trace-control.c b/ltt/ltt-trace-control.c
> index c1c44c6..63cbb29 100644
> --- a/ltt/ltt-trace-control.c
> +++ b/ltt/ltt-trace-control.c
> @@ -846,6 +846,8 @@ static ssize_t marker_info_read(struct file *filp, char __user *ubuf,
>  	len = 0;
>  	buf = (char *)__get_free_page(GFP_KERNEL);
>  
> +	lock_markers();
> +
>  	marker_iter_reset(&iter);
>  	marker_iter_start(&iter);
>  	for (; iter.marker != NULL; marker_iter_next(&iter)) {
> @@ -872,6 +874,8 @@ static ssize_t marker_info_read(struct file *filp, char __user *ubuf,
>  	}
>  	marker_iter_stop(&iter);
>  
> +	unlock_markers();
> +
>  	if (len >= PAGE_SIZE) {
>  		len = PAGE_SIZE;
>  		buf[PAGE_SIZE] = '\0';
> @@ -958,6 +962,8 @@ static int build_marker_control_files(void)
>  	if (!markers_control_dir)
>  		return -EEXIST;
>  
> +	lock_markers();
> +
>  	marker_iter_reset(&iter);
>  	marker_iter_start(&iter);
>  	for (; iter.marker != NULL; marker_iter_next(&iter)) {
> @@ -966,6 +972,9 @@ static int build_marker_control_files(void)
>  			goto err_build_fail;
>  	}
>  	marker_iter_stop(&iter);
> +
> +	unlock_markers();
> +
>  	return 0;
>  
>  err_build_fail:
> @@ -991,6 +1000,8 @@ static int remove_marker_control_dir(struct module *mod, struct marker *marker)
>  		return -ENOENT;
>  	name = marker_d->d_name.name;
>  
> +	lock_markers();
> +
>  	marker_iter_reset(&iter);
>  	marker_iter_start(&iter);
>  	for (; iter.marker != NULL; marker_iter_next(&iter)) {
> @@ -1008,6 +1019,7 @@ static int remove_marker_control_dir(struct module *mod, struct marker *marker)
>  
>  end:
>  	marker_iter_stop(&iter);
> +	unlock_markers();
>  	return 0;
>  }
>  
> -- 
> 1.5.4.rc3
> 
> 
> 

-- 
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68