livepatch: Remove duplicate warning about missing reliable stacktrace support

WARN_ON_ONCE() could not be called safely under rq lock because
of console deadlock issues. Moreover WARN_ON_ONCE() is superfluous in
klp_check_stack(), because stack_trace_save_tsk_reliable() cannot return
-ENOSYS thanks to klp_have_reliable_stack() check in
klp_try_switch_task().

[ mbenes: changelog edited ]
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>

diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c
index cb85dae..3c764e7 100644 (file)
--- a/kernel/livepatch/transition.c
+++ b/kernel/livepatch/transition.c
@@ -259,7 +259,6 @@ static int klp_check_stack(struct task_struct *task, char *err_buf)
        int ret, nr_entries;
 
        ret = stack_trace_save_tsk_reliable(task, entries, ARRAY_SIZE(entries));
-       WARN_ON_ONCE(ret == -ENOSYS);
        if (ret < 0) {
                snprintf(err_buf, STACK_ERR_BUF_SIZE,
                         "%s: %s:%d has an unreliable stack\n",