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

[lijiang]

On Thu, Oct 14, 2021 at 12:03 AM <crash-utility-request at redhat.com> wrote:
> Date: Wed, 13 Oct 2021 10:56:39 +0200
> From: Alexander Egorenkov <egorenar at linux.ibm.com>
> To: crash-utility at redhat.com
> Subject: [Crash-utility] [PATCH 1/1] Handle task_struct cpu member
>         changes in linux-next
> Message-ID: <20211013085639.192233-1-egorenar at linux.ibm.com>
> Content-Type: text/plain; charset="US-ASCII"
>
> 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>