File bcc-bsc1172493-Make-reading-blacklist-optional.patch of Package bcc

From 5558e36bd97ace7bc3efe3a70d0c9d4fc0d34e2a Mon Sep 17 00:00:00 2001
From: Ivan Babrou <github@ivan.computer>
Date: Fri, 29 May 2020 15:33:25 -0700
Subject: [PATCH] Make reading blacklist from debugfs optional

With lockdown enabled one sees the following:

```
$ sudo /usr/share/bcc/tools/funccount -Ti 1 run_timer_softirq
[Errno 1] Operation not permitted: '/sys/kernel/debug/tracing/../kprobes/blacklist'
```

Which is accompanied by the following in `dmesg`:

```
[Fri May 29 22:12:47 2020] Lockdown: funccount: debugfs access is restricted; see man kernel_lockdown.7
```

Since blacklist is not a required feature, let's make
reading from it optional, so that bcc can work out of the box.
---
 src/python/bcc/__init__.py | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/src/python/bcc/__init__.py b/src/python/bcc/__init__.py
index 8496ee62..749ebfe5 100644
--- a/src/python/bcc/__init__.py
+++ b/src/python/bcc/__init__.py
@@ -546,8 +546,15 @@ class BPF(object):
 
     @staticmethod
     def get_kprobe_functions(event_re):
-        with open("%s/../kprobes/blacklist" % TRACEFS, "rb") as blacklist_f:
-            blacklist = set([line.rstrip().split()[1] for line in blacklist_f])
+        blacklist_file = "%s/../kprobes/blacklist" % TRACEFS
+        try:
+            with open(blacklist_file, "rb") as blacklist_f:
+                blacklist = set([line.rstrip().split()[1] for line in blacklist_f])
+        except IOError as e:
+            if e.errno != errno.EPERM:
+                raise e
+            blacklist = set([])
+
         fns = []
 
         in_init_section = 0
@@ -607,7 +614,7 @@ class BPF(object):
         global _num_open_probes
         del self.kprobe_fds[name]
         _num_open_probes -= 1
- 
+
     def _add_uprobe_fd(self, name, fd):
         global _num_open_probes
         self.uprobe_fds[name] = fd
@@ -643,7 +650,7 @@ class BPF(object):
             if name.startswith(prefix):
                 return self.get_syscall_fnname(name[len(prefix):])
         return name
-       
+
     def attach_kprobe(self, event=b"", event_off=0, fn_name=b"", event_re=b""):
         event = _assert_is_bytes(event)
         fn_name = _assert_is_bytes(fn_name)
-- 
2.25.1