Re: [patch V4 part 1 15/36] kprobes: Lock kprobe_mutex while showing kprobe_blacklist

Alexandre Chartre
2020-05-06T15:40:35Z

On 5/5/20 3:16 PM, Thomas Gleixner wrote:
> From: Masami Hiramatsu <mhiramat@kernel.org>
>
> Lock kprobe_mutex while showing kprobe_blacklist to prevent updating the
> kprobe_blacklist.
>
> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Link: https://lkml.kernel.org/r/158523417665.24735.10253198878535635600.stgit@devnote2
>
> ---
> kernel/kprobes.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)

Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>

alex.

> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -2426,6 +2426,7 @@ static const struct file_operations debu
> /* kprobes/blacklist -- shows which functions can not be probed */
> static void *kprobe_blacklist_seq_start(struct seq_file *m, loff_t *pos)
> {
> + mutex_lock(&kprobe_mutex);
> return seq_list_start(&kprobe_blacklist, *pos);
> }
>
> @@ -2452,10 +2453,15 @@ static int kprobe_blacklist_seq_show(str
> return 0;
> }
>
> +static void kprobe_blacklist_seq_stop(struct seq_file *f, void *v)
> +{
> + mutex_unlock(&kprobe_mutex);
> +}
> +
> static const struct seq_operations kprobe_blacklist_seq_ops = {
> .start = kprobe_blacklist_seq_start,
> .next = kprobe_blacklist_seq_next,
> - .stop = kprobe_seq_stop, /* Reuse void function */
> + .stop = kprobe_blacklist_seq_stop,
> .show = kprobe_blacklist_seq_show,
> };
>
>