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| author | Chengming Zhou <zhouchengming@bytedance.com> | 2022-03-12 23:22:20 +0800 |
|---|---|---|
| committer | Petr Mladek <pmladek@suse.com> | 2022-03-17 19:02:30 +0100 |
| commit | 2957308343fa7c621df9f342fab88cb970b8d5f3 (patch) | |
| tree | ab8a8824eb612fbcb7424cab05fa11438430b50d /kernel/livepatch | |
| parent | 77dbd72b982ca648b42b4feac5f8b2ea55e4ed09 (diff) | |
| download | linux-stable-2957308343fa7c621df9f342fab88cb970b8d5f3.tar.gz linux-stable-2957308343fa7c621df9f342fab88cb970b8d5f3.tar.bz2 linux-stable-2957308343fa7c621df9f342fab88cb970b8d5f3.zip | |
livepatch: Don't block removal of patches that are safe to unload
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
Diffstat (limited to 'kernel/livepatch')
| -rw-r--r-- | kernel/livepatch/transition.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c index 5683ac0d2566..77ef45a1e0a3 100644 --- a/kernel/livepatch/transition.c +++ b/kernel/livepatch/transition.c @@ -641,6 +641,13 @@ void klp_force_transition(void) 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; + } + } } |