Messages in this thread | | | Subject | Re: [PATCH] livepatch: fix race between enabled_store() and klp_unregister_patch() | From | Jiri Slaby <> | Date | Tue, 1 Dec 2015 15:28:19 +0100 |
| |
On 12/01/2015, 03:13 PM, Petr Mladek wrote: > --- a/kernel/livepatch/core.c > +++ b/kernel/livepatch/core.c > @@ -612,7 +612,19 @@ static ssize_t enabled_store(struct kobject *kobj, struct kobj_attribute *attr, > > patch = container_of(kobj, struct klp_patch, kobj); > > - mutex_lock(&klp_mutex); > + /* > + * Avoid a deadlock with kobject_put(&patch->kobj) that is > + * called under klp_mutex. Bail out when the patch is not > + * longer registered. > + */ > + if (!mutex_trylock(&klp_mutex)) {
This introduces false positives. Deleting/enabling/disabling/other_op_under_klp_mutex of an unrelated patch may now cause enabled_store to fail. Hence I don't like this approach at all.
thanks, -- js suse labs
| |