lkml.org 
[lkml]   [2014]   [Jun]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH 4/4] tracing/uprobes: Fix the usage of uprobe_buffer_enable() in probe_event_enable()
Date
On Fri, 27 Jun 2014 19:01:46 +0200, Oleg Nesterov wrote:
> The usage of uprobe_buffer_enable() added by dcad1a20 is very wrong,
>
> 1. uprobe_buffer_enable() and uprobe_buffer_disable() are not balanced,
> _enable() should be called only if !enabled.
>
> 2. If uprobe_buffer_enable() fails probe_event_enable() should clear
> tp.flags and free event_file_link.
>
> 3. If uprobe_register() fails it should do uprobe_buffer_disable().
>
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>

Thanks for the fix.

Acked-by: Namhyung Kim <namhyung@kernel.org>


> ---
> kernel/trace/trace_uprobe.c | 31 +++++++++++++++++++------------
> 1 files changed, 19 insertions(+), 12 deletions(-)
>
> diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
> index c4cf0ab..3c9b97e 100644
> --- a/kernel/trace/trace_uprobe.c
> +++ b/kernel/trace/trace_uprobe.c
> @@ -911,26 +911,33 @@ probe_event_enable(struct trace_uprobe *tu, struct ftrace_event_file *file,
> tu->tp.flags |= TP_FLAG_PROFILE;
> }
>
> - ret = uprobe_buffer_enable();
> - if (ret < 0)
> - return ret;
> -
> WARN_ON(!uprobe_filter_is_empty(&tu->filter));
>
> if (enabled)
> return 0;
>
> + ret = uprobe_buffer_enable();
> + if (ret)
> + goto err_flags;
> +
> tu->consumer.filter = filter;
> ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
> - if (ret) {
> - if (file) {
> - list_del(&link->list);
> - kfree(link);
> - tu->tp.flags &= ~TP_FLAG_TRACE;
> - } else
> - tu->tp.flags &= ~TP_FLAG_PROFILE;
> - }
> + if (ret)
> + goto err_buffer;
>
> + return 0;
> +
> + err_buffer:
> + uprobe_buffer_disable();
> +
> + err_flags:
> + if (file) {
> + list_del(&link->list);
> + kfree(link);
> + tu->tp.flags &= ~TP_FLAG_TRACE;
> + } else {
> + tu->tp.flags &= ~TP_FLAG_PROFILE;
> + }
> return ret;
> }


\
 
 \ /
  Last update: 2014-06-30 09:01    [W:0.189 / U:1.152 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site