From f12fa28595b0dbab4ef33972832f355dc305db95 Mon Sep 17 00:00:00 2001
From: Avi Kivity <avi@cloudius-systems.com>
Date: Tue, 12 Feb 2013 11:29:36 +0200
Subject: [PATCH] gdb: improved running thread detection
Detect running threads by checking whether any cpu's rsp is within the thread
stack. If so, the thread is running on that cpu, and the saved context is
ignored as stale. This improves 'osv info threads' greatly.
It doesn't work all that well for threads taking interrupts though.
---
scripts/loader.py | 67 ++++++++++++++++++++++++++++++++++++++---------
1 file changed, 55 insertions(+), 12 deletions(-)
diff --git a/scripts/loader.py b/scripts/loader.py
index 322e0eb04..bba8b181b 100644
--- a/scripts/loader.py
+++ b/scripts/loader.py
@@ -75,15 +75,15 @@ class osv_heap(gdb.Command):
print page_range, page_range['size']
self.show(node['right_'])
+ulong_type = gdb.lookup_type('unsigned long')
+
def ulong(x):
+ x = x.cast(ulong_type)
+ x = long(x)
if x < 0:
- print x
x += 1L << 64
- print x
return x
-ulong_type = gdb.lookup_type('unsigned long')
-
class osv_syms(gdb.Command):
def __init__(self):
gdb.Command.__init__(self, 'osv syms',
@@ -105,11 +105,42 @@ class osv_info(gdb.Command):
gdb.Command.__init__(self, 'osv info', gdb.COMMAND_USER,
gdb.COMPLETE_COMMAND, True)
+class cpu(object):
+ def __init__(self, cpu_thread):
+ self.load(cpu_thread)
+ def load(self, cpu_thread):
+ self.cpu_thread = cpu_thread
+ self.id = cpu_thread.num - 1
+ cur = gdb.selected_thread()
+ try:
+ self.cpu_thread.switch()
+ old = gdb.selected_frame()
+ try:
+ gdb.newest_frame().select()
+ self.rsp = ulong(gdb.parse_and_eval('$rsp'))
+ self.rbp = ulong(gdb.parse_and_eval('$rbp'))
+ self.rip = ulong(gdb.parse_and_eval('$rip'))
+ finally:
+ old.select()
+ finally:
+ cur.switch()
+ g_cpus = gdb.parse_and_eval('sched::cpus._M_impl._M_start')
+ self.obj = g_cpus + self.id
+
class vmstate(object):
def __init__(self):
self.reload()
def reload(self):
+ self.load_cpu_list()
self.load_thread_list()
+ def load_cpu_list(self):
+ # cause gdb to initialize thread list
+ gdb.execute('info threads', False, True)
+ cpu_list = {}
+ for cpu_thread in gdb.selected_inferior().threads():
+ c = cpu(cpu_thread)
+ cpu_list[c.id] = c
+ self.cpu_list = cpu_list
def load_thread_list(self):
ret = []
thread_list = gdb.lookup_global_symbol('sched::thread_list').value()
@@ -126,34 +157,46 @@ class vmstate(object):
ret.append(t.dereference())
node = node['next_']
self.thread_list = ret
+ def cpu_from_thread(self, thread):
+ stack = thread['_attr']['stack']
+ stack_begin = ulong(stack['begin'])
+ stack_size = ulong(stack['size'])
+ for c in self.cpu_list.viewvalues():
+ if c.rsp > stack_begin and c.rsp <= stack_begin + stack_size:
+ return c
+ return None
class thread_context(object):
- def __init__(self, thread):
+ def __init__(self, thread, state):
self.old_frame = gdb.selected_frame()
self.new_frame = gdb.newest_frame()
self.new_frame.select()
- self.running = (not long(thread['_on_runqueue'])
- and not long(thread['_waiting']['_M_base']['_M_i']))
self.old_rsp = ulong(gdb.parse_and_eval('$rsp').cast(ulong_type))
self.old_rip = ulong(gdb.parse_and_eval('$rip').cast(ulong_type))
self.old_rbp = ulong(gdb.parse_and_eval('$rbp').cast(ulong_type))
- if not self.running:
+ self.running_cpu = state.cpu_from_thread(thread)
+ self.vm_thread = gdb.selected_thread()
+ if not self.running_cpu:
self.old_frame.select()
self.new_rsp = thread['_state']['rsp'].cast(ulong_type)
def __enter__(self):
self.new_frame.select()
- if not self.running:
+ if not self.running_cpu:
gdb.execute('set $rsp = %s' % (self.new_rsp + 16))
inf = gdb.selected_inferior()
stack = inf.read_memory(self.new_rsp, 16)
(new_rip, new_rbp) = struct.unpack('qq', stack)
gdb.execute('set $rip = %s' % (new_rip + 1))
gdb.execute('set $rbp = %s' % new_rbp)
+ else:
+ self.running_cpu.cpu_thread.switch()
def __exit__(self, *_):
- if not self.running:
+ if not self.running_cpu:
gdb.execute('set $rsp = %s' % self.old_rsp)
gdb.execute('set $rip = %s' % self.old_rip)
gdb.execute('set $rbp = %s' % self.old_rbp)
+ else:
+ self.vm_thread.switch()
self.old_frame.select()
class osv_info_threads(gdb.Command):
@@ -163,7 +206,7 @@ class osv_info_threads(gdb.Command):
def invoke(self, arg, for_tty):
state = vmstate()
for t in state.thread_list:
- with thread_context(t):
+ with thread_context(t, state):
cpu = t['_cpu']
fr = gdb.selected_frame()
sal = fr.find_sal()
@@ -208,7 +251,7 @@ class osv_thread_apply_all(gdb.Command):
state = vmstate()
for t in state.thread_list:
gdb.write('thread %s\n\n' % t.address)
- with thread_context(t):
+ with thread_context(t, state):
gdb.execute(arg, from_tty)
gdb.write('\n')
--
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