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    SubjectRe: [PATCH v2 bpf-next 2/4] bpf: introduce helper bpf_get_task_stak()
    On Fri, Jun 26, 2020 at 1:17 PM Andrii Nakryiko
    <andrii.nakryiko@gmail.com> wrote:
    >
    > On Thu, Jun 25, 2020 at 5:14 PM Song Liu <songliubraving@fb.com> wrote:
    > >
    > > Introduce helper bpf_get_task_stack(), which dumps stack trace of given
    > > task. This is different to bpf_get_stack(), which gets stack track of
    > > current task. One potential use case of bpf_get_task_stack() is to call
    > > it from bpf_iter__task and dump all /proc/<pid>/stack to a seq_file.
    > >
    > > bpf_get_task_stack() uses stack_trace_save_tsk() instead of
    > > get_perf_callchain() for kernel stack. The benefit of this choice is that
    > > stack_trace_save_tsk() doesn't require changes in arch/. The downside of
    > > using stack_trace_save_tsk() is that stack_trace_save_tsk() dumps the
    > > stack trace to unsigned long array. For 32-bit systems, we need to
    > > translate it to u64 array.
    > >
    > > Signed-off-by: Song Liu <songliubraving@fb.com>
    > > ---
    >
    > Looks great, I just think that there are cases where user doesn't
    > necessarily has valid task_struct pointer, just pid, so would be nice
    > to not artificially restrict such cases by having extra helper.
    >
    > Acked-by: Andrii Nakryiko <andriin@fb.com>

    oh, please also fix a typo in the subject, it will make grepping more
    frustrating

    [...]

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