Re: [RFC PATCH v2 06/18] x86: dump_trace() error handling

Josh Poimboeuf
2016-04-29T14:00:45Z

On Fri, Apr 29, 2016 at 09:45:58PM +0800, Minfei Huang wrote:
> On 04/28/16 at 03:44P, Josh Poimboeuf wrote:
> > In preparation for being able to determine whether a given stack trace
> > is reliable, allow the stacktrace_ops functions to propagate errors to
> > dump_trace().
>
> Hi, Josh.
>
> Have you considered to make walk_stack function as non-return function,
> since there is no obvious error during detecting the frame points?

If you look at the next patch 07/18, there are several cases where
walk_stack (print_context_stack_reliable) returns an error.

For example, if a function gets preempted before it gets a chance to
save the frame pointer, the function's caller would get skipped on the
stack trace. So for preempted tasks, we always have to consider their
stacks unreliable.

--
Josh