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Date: Mon, 30 Nov 2015 11:54:37 +0800 From: Li Bin <huawei.libin@...wei.com> To: <jpoimboe@...hat.com>, <sjenning@...hat.com>, <jikos@...nel.org>, <vojtech@...e.com> CC: <live-patching@...r.kernel.org>, <linux-kernel@...r.kernel.org>, <guohanjun@...wei.com>, <dingtianhong@...wei.com>, <xiexiuqi@...wei.com>, <zhouchengming1@...wei.com> Subject: [PATCH] livepatch: fix race between enabled_store() and klp_unregister_patch() 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@...wei.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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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