[Crash-utility] [PATCH 1/1] Handle task_struct cpu member changes in linux-next

[HAGIO KAZUHITO(萩尾 一仁)]

-----Original Message-----
> > Kernel commit bcf9033e5449bdcaa9bed46467a7141a8049dadb
> > ("sched: move CPU field back into thread_info if THREAD_INFO_IN_TASK=y")
> > moved the member cpu of task_struct back into thread_info.
> >
> > https://lkml.org/lkml/2021/9/30/517
> >
> > This fixes the following problem:
> >
> > please wait... (gathering task table data)
> > crash: invalid structure member offset: task_struct_cpu
> >        FILE: task.c  LINE: 2904  FUNCTION: add_context()
> >
> > [/usr/bin/crash] error trace: 114840a => 115560a => 114e360 => 11d6394
> >
> >   11d6394: (undetermined)
> >   114e360: (undetermined)
> >   115560a: (undetermined)
> >   114840a: task_init+4634
> >
> > Signed-off-by: Alexander Egorenkov <egorenar at linux.ibm.com>
> > ---
> >  task.c | 7 ++++---
> >  1 file changed, 4 insertions(+), 3 deletions(-)
> >
> > diff --git a/task.c b/task.c
> > index 672b41697e75..bb6a5da8ad33 100644
> > --- a/task.c
> > +++ b/task.c
> > @@ -278,8 +278,10 @@ task_init(void)
> >         } else if (VALID_MEMBER(task_struct_stack))
> >                 MEMBER_OFFSET_INIT(task_struct_thread_info, "task_struct", "stack");
> >
> > +       MEMBER_OFFSET_INIT(task_struct_cpu, "task_struct", "cpu");
> > +
> >         if (VALID_MEMBER(task_struct_thread_info)) {
> > -               if (tt->flags & THREAD_INFO_IN_TASK) {
> > +               if (tt->flags & THREAD_INFO_IN_TASK && VALID_MEMBER(task_struct_cpu)) {
> >                         MEMBER_OFFSET_INIT(thread_info_flags, "thread_info", "flags");
> >                         /* (unnecessary) reminders */
> >                         ASSIGN_OFFSET(thread_info_task) = INVALID_OFFSET;
> > @@ -315,7 +317,6 @@ task_init(void)
> >          MEMBER_OFFSET_INIT(task_struct_has_cpu, "task_struct", "has_cpu");
> >          MEMBER_OFFSET_INIT(task_struct_cpus_runnable,
> >                 "task_struct", "cpus_runnable");
> > -       MEMBER_OFFSET_INIT(task_struct_cpu, "task_struct", "cpu");
> >         MEMBER_OFFSET_INIT(task_struct_active_mm, "task_struct", "active_mm");
> >         MEMBER_OFFSET_INIT(task_struct_next_run, "task_struct", "next_run");
> >         MEMBER_OFFSET_INIT(task_struct_flags, "task_struct", "flags");
> > @@ -2900,7 +2901,7 @@ add_context(ulong task, char *tp)
> >                 else
> >                         tc->thread_info = ULONG(tp + OFFSET(task_struct_thread_info));
> >                 fill_thread_info(tc->thread_info);
> > -               if (tt->flags & THREAD_INFO_IN_TASK)
> > +               if (tt->flags & THREAD_INFO_IN_TASK && VALID_MEMBER(task_struct_cpu))
> >                         processor_addr = (int *) (tp + OFFSET(task_struct_cpu));
> >                 else
> >                         processor_addr = (int *) (tt->thread_info +
> > --
> > 2.31.1
> 
> Thank you for the fix, Alexander.
> Acked-by: Lianbo Jiang <lijiang at redhat.com>

ok, we will merge this when the kernel commit gets into mainline.

Thanks,
Kazu