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

[Alexandre Chartre]

On 5/5/20 3:16 PM, Thomas Gleixner wrote:

From: Masami Hiramatsu <mhira...@kernel.org>

Lock kprobe_mutex while showing kprobe_blacklist to prevent updating the
kprobe_blacklist.

Signed-off-by: Masami Hiramatsu <mhira...@kernel.org>
Signed-off-by: Thomas Gleixner <t...@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.char...@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,
  };