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SubjectRe: [PATCH] stacktrace: fix CONFIG_ARCH_STACKWALK stack_trace_save_tsk_reliable return
On Fri, May 17, 2019 at 02:51:17PM -0400, Joe Lawrence wrote:
> Miroslav reported that the livepatch self-tests were failing,
> specifically a case in which the consistency model ensures that we do
> not patch a current executing function, "TEST: busy target module".
>
> Recent renovations to stack_trace_save_tsk_reliable() left it returning
> only an -ERRNO success indication in some configuration combinations:
>
> klp_check_stack()
> ret = stack_trace_save_tsk_reliable()
> #ifdef CONFIG_ARCH_STACKWALK && CONFIG_HAVE_RELIABLE_STACKTRACE
> stack_trace_save_tsk_reliable()
> ret = arch_stack_walk_reliable()
> return 0
> return -EINVAL
> ...
> return ret;
> ...
> if (ret < 0)
> /* stack_trace_save_tsk_reliable error */
> nr_entries = ret; << 0
>
> Previously (and currently for !CONFIG_ARCH_STACKWALK &&
> CONFIG_HAVE_RELIABLE_STACKTRACE) stack_trace_save_tsk_reliable()
> returned the number of entries that it consumed in the passed storage
> array.
>
> In the case of the above config and trace, be sure to return the
> stacktrace_cookie.len on stack_trace_save_tsk_reliable() success.
>
> Fixes: 25e39e32b0a3f ("livepatch: Simplify stack trace retrieval")
> Reported-by: Miroslav Benes <mbenes@suse.cz>
> Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>

It's great to see the livepatch selftests working and finding
regressions.

Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>

--
Josh

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