Update BCC docs with more common issues examples
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
diff --git a/BCC.md b/BCC.md
index 6adc058..7428b74 100644
--- a/BCC.md
+++ b/BCC.md
@@ -81,6 +81,8 @@
Common Issues
-------------
+Here are some common issues you may face when running different BCC tools.
+
* Issue 1: Headers are missing on the target device.
Symptom: This will usually result in an error like the following:
@@ -110,3 +112,43 @@
extern char _stext[];
```
+
+* Issue 2: `CONFIG_KPROBES` isn't enabled.
+
+Symptom: This will result in an error like the following:
+```
+Traceback (most recent call last):
+ File "/usr/share/bcc/tools/cachetop", line 263, in <module>
+ curses.wrapper(handle_loop, args)
+ File "/usr/lib/python2.7/curses/wrapper.py", line 43, in wrapper
+ return func(stdscr, *args, **kwds)
+ File "/usr/share/bcc/tools/cachetop", line 172, in handle_loop
+ b.attach_kprobe(event="add_to_page_cache_lru", fn_name="do_count")
+ File "/usr/lib/python2.7/dist-packages/bcc/__init__.py", line 543, in
+attach_kprobe
+ fn = self.load_func(fn_name, BPF.KPROBE)
+ File "/usr/lib/python2.7/dist-packages/bcc/__init__.py", line 355, in
+load_func
+ (func_name, errstr))
+Exception: Failed to load BPF program do_count: Invalid argument
+```
+
+* Issue 3: `CONFIG_BPF_SYSCALL` isn't enabled.
+
+Symptom: This will result in an error like the following:
+```
+Traceback (most recent call last):
+ File "/usr/share/bcc/tools/cachetop", line 263, in <module>
+ curses.wrapper(handle_loop, args)
+ File "/usr/lib/python2.7/curses/wrapper.py", line 43, in wrapper
+ return func(stdscr, *args, **kwds)
+ File "/usr/share/bcc/tools/cachetop", line 172, in handle_loop
+ b.attach_kprobe(event="add_to_page_cache_lru", fn_name="do_count")
+ File "/usr/lib/python2.7/dist-packages/bcc/__init__.py", line 543, in
+attach_kprobe
+ fn = self.load_func(fn_name, BPF.KPROBE)
+ File "/usr/lib/python2.7/dist-packages/bcc/__init__.py", line 355, in
+load_func
+ (func_name, errstr))
+Exception: Failed to load BPF program do_count: Invalid argument
+```
