[PATCH v3] scripts/gdb: fix 'lx-timerlist' on newer kernel

[Lin Ma]

After commit 511885d7061e ("lib/timerqueue: Rely on rbtree semantics for
next timer"), the struct timerqueue_head changes the internal field hence
causes the old lx-timerlist command keeps reporting errors.

This fix adds a simple version comparison and necessary code for
traversing timerqueue on a newer kernel. Moreover, it fixes some
python 3.X compatibility bugs.

Test with python 2.7 and python 3.6
Test with gdb 10.2

Signed-off-by: Lin Ma <linma@xxxxxxxxxx>
---
V1->V2: remove the support of old versions, fix typo and adjust the
        commit message
V2->V3: remove redundant re package
 scripts/gdb/linux/timerlist.py | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/scripts/gdb/linux/timerlist.py b/scripts/gdb/linux/timerlist.py
index 071d0dd5a634..85072be2a196 100644
--- a/scripts/gdb/linux/timerlist.py
+++ b/scripts/gdb/linux/timerlist.py
@@ -43,8 +43,10 @@ def print_timer(rb_node, idx):
 
 
 def print_active_timers(base):
-    curr = base['active']['next']['node']
-    curr = curr.address.cast(rbtree.rb_node_type.get_type().pointer())
+    # 511885d7061e ("lib/timerqueue: Rely on rbtree semantics for next timer")
+    leftmost = base['active']['rb_root']['rb_leftmost']
+    curr = leftmost.cast(rbtree.rb_node_type.get_type().pointer())
+
     idx = 0
     while curr:
         yield print_timer(curr, idx)
@@ -73,10 +75,9 @@ def print_cpu(hrtimer_bases, cpu, max_clock_bases):
     ts = cpus.per_cpu(tick_sched_ptr, cpu)
 
     text = "cpu: {}\n".format(cpu)
-    for i in xrange(max_clock_bases):
+    for i in range(max_clock_bases):
         text += " clock {}:\n".format(i)
         text += print_base(cpu_base['clock_base'][i])
-
         if constants.LX_CONFIG_HIGH_RES_TIMERS:
             fmts = [("  .{}   : {} nsecs", 'expires_next'),
                     ("  .{}    : {}", 'hres_active'),
@@ -165,7 +166,7 @@ def pr_cpumask(mask):
         i -= 1
         start = i * 2
         end = start + 2
-        chunks.append(buf[start:end])
+        chunks.append(str(buf[start:end]))
         if i != 0 and i % 4 == 0:
             chunks.append(',')
 
@@ -184,7 +185,7 @@ class LxTimerList(gdb.Command):
 
     def invoke(self, arg, from_tty):
         hrtimer_bases = gdb.parse_and_eval("&hrtimer_bases")
-        max_clock_bases = gdb.parse_and_eval("HRTIMER_MAX_CLOCK_BASES")
+        max_clock_bases = gdb.parse_and_eval("(int)HRTIMER_MAX_CLOCK_BASES")
 
         text = "Timer List Version: gdb scripts\n"
         text += "HRTIMER_MAX_CLOCK_BASES: {}\n".format(max_clock_bases)
-- 
2.17.1