Re: [PATCH 3/6] uprobes/tracing: Ensure inode != NULL in create_trace_uprobe()

[Srikar Dronamraju <srikar@linux.vnet.ibm.com>]

* Oleg Nesterov <oleg@redhat.com> [2013-01-31 20:18:22]:

> probe_event_enable/disable() check tu->inode != NULL at the start.
> This is ugly, if igrab() can fail create_trace_uprobe() should not
> succeed and "postpone" the failure.
> 
> Note: alloc_uprobe() should probably check igrab() != NULL as well.
> 
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>

Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

> ---
>  kernel/trace/trace_uprobe.c |    6 ++++--
>  1 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
> index 7b75949..f02bbec 100644
> --- a/kernel/trace/trace_uprobe.c
> +++ b/kernel/trace/trace_uprobe.c
> @@ -255,6 +255,8 @@ static int create_trace_uprobe(int argc, char **argv)
> 
>  	inode = igrab(path.dentry->d_inode);
>  	path_put(&path);
> +	if (!inode)
> +		goto fail_address_parse;
> 
>  	ret = kstrtoul(arg, 0, &offset);
>  	if (ret)
> @@ -539,7 +541,7 @@ static int probe_event_enable(struct trace_uprobe *tu, int flag)
>  	struct uprobe_trace_consumer *utc;
>  	int ret = 0;
> 
> -	if (!tu->inode || tu->consumer)
> +	if (tu->consumer)
>  		return -EINTR;
> 
>  	utc = kzalloc(sizeof(struct uprobe_trace_consumer), GFP_KERNEL);
> @@ -563,7 +565,7 @@ static int probe_event_enable(struct trace_uprobe *tu, int flag)
> 
>  static void probe_event_disable(struct trace_uprobe *tu, int flag)
>  {
> -	if (!tu->inode || !tu->consumer)
> +	if (!tu->consumer)
>  		return;
> 
>  	uprobe_unregister(tu->inode, tu->offset, &tu->consumer->cons);
> -- 
> 1.5.5.1
> 

-- 
Thanks and Regards
Srikar Dronamraju