Messages in this thread Patch in this message | | | From | Li Bin <> | Subject | [PATCH] livepatch: fix race between enabled_store() and klp_unregister_patch() | Date | Mon, 30 Nov 2015 11:54:37 +0800 |
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There is a potential race as following:
CPU0 | CPU1 -----------------------------|----------------------------------- enabled_store() | klp_unregister_patch() | |-mutex_lock(&klp_mutex); |-mutex_lock(&klp_mutex); | |-klp_free_patch(); | |-mutex_unlock(&klp_mutex); |-[process the patch's state]| |-mutex_unlock(&klp_mutex) |
Fix this race condition by adding klp_is_patch_registered() check in enabled_store() after get the lock klp_mutex.
Signed-off-by: Li Bin <huawei.libin@huawei.com> --- kernel/livepatch/core.c | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-)
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index db545cb..50af971 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -614,6 +614,11 @@ static ssize_t enabled_store(struct kobject *kobj, struct kobj_attribute *attr, mutex_lock(&klp_mutex); + if (!klp_is_patch_registered(patch)) { + ret = -EINVAL; + goto err; + } + if (val == patch->state) { /* already in requested state */ ret = -EINVAL; -- 1.7.1
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