[tip:perf/kprobes] kprobes: Show blacklist entries via debugfs

tip-bot for Masami Hiramatsu
2014-04-24T11:01:43Z

Commit-ID: 637247403abff8c963bc7be8002b3f49ea604563
Gitweb: http://git.kernel.org/tip/637247403abff8c963bc7be8002b3f49ea604563
Author: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
AuthorDate: Thu, 17 Apr 2014 17:18:49 +0900
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 24 Apr 2014 10:26:41 +0200

kprobes: Show blacklist entries via debugfs

Show blacklist entries (function names with the address
range) via /sys/kernel/debug/kprobes/blacklist.

Note that at this point the blacklist supports only
in vmlinux, not module. So the list is fixed and
not updated.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Link: http://lkml.kernel.org/r/20140417081849.26341.11609.stgit@ltc230.yrl.intra.hitachi.co.jp
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/kprobes.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++++--------
1 file changed, 53 insertions(+), 8 deletions(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index a21b4e6..3214289 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2249,6 +2249,46 @@ static const struct file_operations debugfs_kprobes_operations = {
.release = seq_release,
};

+/* kprobes/blacklist -- shows which functions can not be probed */
+static void *kprobe_blacklist_seq_start(struct seq_file *m, loff_t *pos)
+{
+ return seq_list_start(&kprobe_blacklist, *pos);
+}
+
+static void *kprobe_blacklist_seq_next(struct seq_file *m, void *v, loff_t *pos)
+{
+ return seq_list_next(v, &kprobe_blacklist, pos);
+}
+
+static int kprobe_blacklist_seq_show(struct seq_file *m, void *v)
+{
+ struct kprobe_blacklist_entry *ent =
+ list_entry(v, struct kprobe_blacklist_entry, list);
+
+ seq_printf(m, "0x%p-0x%p\t%ps\n", (void *)ent->start_addr,
+ (void *)ent->end_addr, (void *)ent->start_addr);
+ return 0;
+}
+
+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 */
+ .show = kprobe_blacklist_seq_show,
+};
+
+static int kprobe_blacklist_open(struct inode *inode, struct file *filp)
+{
+ return seq_open(filp, &kprobe_blacklist_seq_ops);
+}
+
+static const struct file_operations debugfs_kprobe_blacklist_ops = {
+ .open = kprobe_blacklist_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
static void arm_all_kprobes(void)
{
struct hlist_head *head;
@@ -2372,19 +2412,24 @@ static int __init debugfs_kprobe_init(void)

file = debugfs_create_file("list", 0444, dir, NULL,
&debugfs_kprobes_operations);
- if (!file) {
- debugfs_remove(dir);
- return -ENOMEM;
- }
+ if (!file)
+ goto error;

file = debugfs_create_file("enabled", 0600, dir,
&value, &fops_kp);
- if (!file) {
- debugfs_remove(dir);
- return -ENOMEM;
- }
+ if (!file)
+ goto error;
+
+ file = debugfs_create_file("blacklist", 0444, dir, NULL,
+ &debugfs_kprobe_blacklist_ops);
+ if (!file)
+ goto error;

return 0;
+
+error:
+ debugfs_remove(dir);
+ return -ENOMEM;
}

late_initcall(debugfs_kprobe_init);