[Crash-utility] [PATCH v2] Add ending identifier for union when parsing task structure

[lijiang]

On Mon, Aug 29, 2022 at 3:21 PM <crash-utility-request at redhat.com> wrote:

> Date: Mon, 29 Aug 2022 07:15:15 +0000
> From: HAGIO KAZUHITO(?????)  <k-hagio-ab at nec.com>
> To: "Discussion list for crash utility usage, maintenance and
>         development" <crash-utility at redhat.com>, Tao Liu <ltao at redhat.com>
> Subject: Re: [Crash-utility] [PATCH v2] Add ending identifier for
>         union when parsing task structure
> Message-ID: <b5f22630-9649-20a2-6233-f229f76353dc at nec.com>
> Content-Type: text/plain; charset="utf-8"
>
> On 2022/08/25 15:39, Tao Liu wrote:
> > Previously, the start and end identifier for union is "  {\n"
> > and "  }, \n". However the end identifier is not always as
> > expected. "  },\n" can also be the end identifier. As a result,
> > variable "randomized" is in incorrect state after union, and
> > fails to identify the later struct members. For example, we can
> > reproduce the issue as follows:
> >
> >      crash> task
> >      PID: 847      TASK: ffff94f8038f4000  CPU: 72   COMMAND:
> "khungtaskd"
> >      struct task_struct {
> >        thread_info = {
> >       flags = 2148024320,
> >       status = 0,
> >       preempt_lazy_count = 0
> >        },
> >        {
> >       <the union>
> >        },
> >        ...
> >        wake_entry = {
> >       next = 0x0
> >        },
> >        ...
> >
> > Before patch:
> >
> >      crash> task -R wake_entry
> >      PID: 847      TASK: ffff94f8038f4000  CPU: 72   COMMAND:
> "khungtaskd"
> >
> > After patch:
> >
> >      crash> task -R wake_entry
> >      PID: 847      TASK: ffff94f8038f4000  CPU: 72   COMMAND:
> "khungtaskd"
> >        wake_entry = {
> >       next = 0x0
> >        },
> >
> > Signed-off-by: Tao Liu <ltao at redhat.com>
> > ---
> >
> > v1 -> v2: Rewrite the commit log.
>
> Thanks for the update.
>
> I will add "with gdb-10.2" to the commit log when applying.
>
>
This is indeed a specific gdb-10.2 issue. They have different output styles
between gdb-7.6 and gdb-10.2.


> Acked-by: Kazuhito Hagio <k-hagio-ab at nec.com>
>
> Thanks,
> Kazu
>
>
> >
> > ---
> >   task.c | 3 ++-
> >   1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/task.c b/task.c
> > index 071c787..db2abc8 100644
> > --- a/task.c
> > +++ b/task.c
> > @@ -3436,7 +3436,8 @@ parse_task_thread(int argcnt, char *arglist[],
> struct task_context *tc) {
> >           while (fgets(buf, BUFSIZE, pc->tmpfile)) {
> >               if (STREQ(buf, "  {\n"))
> >                       randomized = TRUE;
> > -             else if (randomized && STREQ(buf, "  }, \n"))
> > +             else if (randomized &&
> > +                      (STREQ(buf, "  }, \n") || STREQ(buf, "  },\n")))
>

This change looks good, and the test is ok.  So for the v2: Ack.

Thanks.
Lianbo

>                       randomized = FALSE;
> >
> >               if (strlen(lookfor2)) {
>
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