module_put() is not called for a patch with "forced" flag. It should
block the removal of the livepatch module when the code might still
be in use after forced transition.
klp_force_transition() currently sets "forced" flag for all patches on
the list.
In fact, any patch can be safely unloaded when it passed through
the consistency model in KLP_UNPATCHED transition.
In other words, the "forced" flag must be set only for livepatches
that are being removed. In particular, set the "forced" flag:
+ only for klp_transition_patch when the transition to KLP_UNPATCHED
state was forced.
+ all replaced patches when the transition to KLP_PATCHED state was
forced and the patch was replacing the existing patches.
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Petr Mladek <pmladek@suse.com>
[mbenes@suse.cz: wording improvements]
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220312152220.88127-1-zhouchengming@bytedance.com
for_each_possible_cpu(cpu)
klp_update_patch_state(idle_task(cpu));
- klp_for_each_patch(patch)
- patch->forced = true;
+ /* Set forced flag for patches being removed. */
+ if (klp_target_state == KLP_UNPATCHED)
+ klp_transition_patch->forced = true;
+ else if (klp_transition_patch->replace) {
+ klp_for_each_patch(patch) {
+ if (patch != klp_transition_patch)
+ patch->forced = true;
+ }
+ }
}