[tip: core/kprobes] kprobes: Lock kprobe_mutex while showing kprobe_blacklist

tip-bot2 for Masami Hiramatsu
2020-05-12T15:19:07Z

The following commit has been merged into the core/kprobes branch of tip:

Commit-ID: 4fdd88877e5259dcc5e504dca449acc0324d71b9
Gitweb: https://git.kernel.org/tip/4fdd88877e5259dcc5e504dca449acc0324d71b9
Author: Masami Hiramatsu <mhiramat@kernel.org>
AuthorDate: Thu, 26 Mar 2020 23:49:36 +09:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Tue, 12 May 2020 17:15:31 +02:00

kprobes: Lock kprobe_mutex while showing kprobe_blacklist

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>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134059.571125195@linutronix.de

---
kernel/kprobes.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 2625c24..570d608 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2420,6 +2420,7 @@ static const struct file_operations debugfs_kprobes_operations = {
/* 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);
}

@@ -2446,10 +2447,15 @@ static int kprobe_blacklist_seq_show(struct seq_file *m, void *v)
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,
};