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

From: Lin Ma
Date: Mon Jan 02 2023 - 04:04:21 EST


Hi Jan,

> > After commit 511885d7061e ("lib/timerqueue: Rely on rbtree semantics for
> > next timer"), the struct timerqueue_head changes internal field hence
> > causes the old lx-timerlist command keeps reporting errors.
> >
> > This fix addes a simple version comparison and necessary code for
>
> typo: "adds"

Thanks, my bad. dx

>
> > traversing timerqueue on a newer kernel. Moreover, it fixes some
> > python 3.X compatibility bugs.
>
> The gdb scripts are in lock-step with the kernel version they can
> inspect. So just move the logic to the current kernel and drop support
> for older versions.

Okay, roger that. Will send another version soon.

Regards
Lin

>
> Jan
>
> >
> > Test with python 2.7 and python 3.6
> > Test with
> > * commit 442284a89a65 ("scripts/gdb: add a timer list command") and
> > * commit 88603b6dc419 ("Linux 6.2-rc2") kernel
> >
> > Signed-off-by: Lin Ma <linma@xxxxxxxxxx>
> > ---
> > scripts/gdb/linux/timerlist.py | 41 ++++++++++++++++++++++------------
> > 1 file changed, 27 insertions(+), 14 deletions(-)
> >
> > diff --git a/scripts/gdb/linux/timerlist.py b/scripts/gdb/linux/timerlist.py
> > index 071d0dd5a634..65d035df253d 100644
> > --- a/scripts/gdb/linux/timerlist.py
> > +++ b/scripts/gdb/linux/timerlist.py
> > @@ -4,6 +4,7 @@
> >
> > import binascii
> > import gdb
> > +import re
> >
> > from linux import constants
> > from linux import cpus
> > @@ -42,9 +43,15 @@ def print_timer(rb_node, idx):
> > return text
> >
> >
> > -def print_active_timers(base):
> > - curr = base['active']['next']['node']
> > - curr = curr.address.cast(rbtree.rb_node_type.get_type().pointer())
> > +def print_active_timers(base, oldver):
> > + # 511885d7061e ("lib/timerqueue: Rely on rbtree semantics for next timer")
> > + if oldver:
> > + curr = base['active']['next']['node']
> > + curr = curr.address.cast(rbtree.rb_node_type.get_type().pointer())
> > + else:
> > + 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)
> > @@ -52,7 +59,7 @@ def print_active_timers(base):
> > idx += 1
> >
> >
> > -def print_base(base):
> > +def print_base(base, oldver):
> > text = " .base: {}\n".format(base.address)
> > text += " .index: {}\n".format(base['index'])
> >
> > @@ -62,21 +69,20 @@ def print_base(base):
> > if constants.LX_CONFIG_HIGH_RES_TIMERS:
> > text += " .offset: {} nsecs\n".format(base['offset'])
> > text += "active timers:\n"
> > - text += "".join([x for x in print_active_timers(base)])
> > + text += "".join([x for x in print_active_timers(base, oldver)])
> > return text
> >
> >
> > -def print_cpu(hrtimer_bases, cpu, max_clock_bases):
> > +def print_cpu(hrtimer_bases, cpu, max_clock_bases, oldver):
> > cpu_base = cpus.per_cpu(hrtimer_bases, cpu)
> > jiffies = gdb.parse_and_eval("jiffies_64")
> > tick_sched_ptr = gdb.parse_and_eval("&tick_cpu_sched")
> > 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])
> > -
> > + text += print_base(cpu_base['clock_base'][i], oldver)
> > if constants.LX_CONFIG_HIGH_RES_TIMERS:
> > fmts = [(" .{} : {} nsecs", 'expires_next'),
> > (" .{} : {}", 'hres_active'),
> > @@ -165,7 +171,7 @@ 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(',')
> >
> > @@ -184,14 +190,21 @@ 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")
> > -
> > - text = "Timer List Version: gdb scripts\n"
> > + max_clock_bases = gdb.parse_and_eval("(int)HRTIMER_MAX_CLOCK_BASES")
> > + banner = gdb.parse_and_eval("(char *)linux_banner").string()
> > + r = re.match(r"^Linux version (.+) \(.*@.*$", banner)
> > + if not r:
> > + gdb.write("failed to load image version")
> > + return
> > + lver = r.group(1)
> > + oldver = lver < '5.3.0-rc1'
> > +
> > + text = "Timer List Version: gdb scripts, old version: {}\n".format(oldver)
> > text += "HRTIMER_MAX_CLOCK_BASES: {}\n".format(max_clock_bases)
> > text += "now at {} nsecs\n".format(ktime_get())
> >
> > for cpu in cpus.each_online_cpu():
> > - text += print_cpu(hrtimer_bases, cpu, max_clock_bases)
> > + text += print_cpu(hrtimer_bases, cpu, max_clock_bases, oldver)
> >
> > if constants.LX_CONFIG_GENERIC_CLOCKEVENTS:
> > if constants.LX_CONFIG_GENERIC_CLOCKEVENTS_BROADCAST:
>
> --
> Siemens AG, Technology
> Competence Center Embedded Linux