fix zfsslower check for zpl_read / zpl_iter (fixes iovisor#4952) (iov…

…isor#4953)

* fix zfsslower/zfsdist check for zpl_read / zpl_iter (fixes iovisor#4952)

This fixes a regression of iovisor#1248: The original fix iovisor#1324 assumed that
BPF.get_kprobe_functions checks the given regex against any substring of
the function name, but 2b203ea later changed get_kprobe_functions to do
re.fullmatch instead.

zfsdist was also not updated since
iovisor@2b203ea
and it the get_kprobe_functions seem to originate from the same
commit as those in zfsslower. So I assume the intend is the same.

Co-authored-by: seb314 <[email protected]>

tools/zfsdist.py

@@ -142,21 +142,21 @@
 b = BPF(text=bpf_text)
 
 # common file functions
-if BPF.get_kprobe_functions(b'zpl_iter'):
+if BPF.get_kprobe_functions(b'zpl_iter.*'):
  b.attach_kprobe(event="zpl_iter_read", fn_name="trace_entry")
  b.attach_kprobe(event="zpl_iter_write", fn_name="trace_entry")
-elif BPF.get_kprobe_functions(b'zpl_aio'):
+elif BPF.get_kprobe_functions(b'zpl_aio.*'):
  b.attach_kprobe(event="zpl_aio_read", fn_name="trace_entry")
  b.attach_kprobe(event="zpl_aio_write", fn_name="trace_entry")
 else:
  b.attach_kprobe(event="zpl_read", fn_name="trace_entry")
  b.attach_kprobe(event="zpl_write", fn_name="trace_entry")
 b.attach_kprobe(event="zpl_open", fn_name="trace_entry")
 b.attach_kprobe(event="zpl_fsync", fn_name="trace_entry")
-if BPF.get_kprobe_functions(b'zpl_iter'):
+if BPF.get_kprobe_functions(b'zpl_iter.*'):
  b.attach_kretprobe(event="zpl_iter_read", fn_name="trace_read_return")
  b.attach_kretprobe(event="zpl_iter_write", fn_name="trace_write_return")
-elif BPF.get_kprobe_functions(b'zpl_aio'):
+elif BPF.get_kprobe_functions(b'zpl_aio.*'):
  b.attach_kretprobe(event="zpl_aio_read", fn_name="trace_read_return")
  b.attach_kretprobe(event="zpl_aio_write", fn_name="trace_write_return")
 else:

tools/zfsslower.py

@@ -264,21 +264,21 @@ def print_event(cpu, data, size):
 b = BPF(text=bpf_text)
 
 # common file functions
-if BPF.get_kprobe_functions(b'zpl_iter'):
+if BPF.get_kprobe_functions(b'zpl_iter.*'):
  b.attach_kprobe(event="zpl_iter_read", fn_name="trace_rw_entry")
  b.attach_kprobe(event="zpl_iter_write", fn_name="trace_rw_entry")
-elif BPF.get_kprobe_functions(b'zpl_aio'):
+elif BPF.get_kprobe_functions(b'zpl_aio.*'):
  b.attach_kprobe(event="zpl_aio_read", fn_name="trace_rw_entry")
  b.attach_kprobe(event="zpl_aio_write", fn_name="trace_rw_entry")
 else:
  b.attach_kprobe(event="zpl_read", fn_name="trace_rw_entry")
  b.attach_kprobe(event="zpl_write", fn_name="trace_rw_entry")
 b.attach_kprobe(event="zpl_open", fn_name="trace_open_entry")
 b.attach_kprobe(event="zpl_fsync", fn_name="trace_fsync_entry")
-if BPF.get_kprobe_functions(b'zpl_iter'):
+if BPF.get_kprobe_functions(b'zpl_iter.*'):
  b.attach_kretprobe(event="zpl_iter_read", fn_name="trace_read_return")
  b.attach_kretprobe(event="zpl_iter_write", fn_name="trace_write_return")
-elif BPF.get_kprobe_functions(b'zpl_aio'):
+elif BPF.get_kprobe_functions(b'zpl_aio.*'):
  b.attach_kretprobe(event="zpl_aio_read", fn_name="trace_read_return")
  b.attach_kretprobe(event="zpl_aio_write", fn_name="trace_write_return")
 else: