Messages in this thread Patch in this message | | | From | Wang ShaoBo <> | Subject | [PATCH] kretprobe: avoid re-registration of the same kretprobe earlier | Date | Tue, 24 Nov 2020 19:57:19 +0800 |
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Our system encountered a re-init error when re-registering same kretprobe, where the kretprobe_instance in rp->free_instances is illegally accessed after re-init.
Implementation to avoid re-registration has been introduced for kprobe before, but lags for register_kretprobe(). We must check if kprobe has been re-registered before re-initializing kretprobe, otherwise it will destroy the data struct of kretprobe registered, which can lead to memory leak, system crash, also some unexpected behaviors.
we use check_kprobe_rereg() to check if kprobe has been re-registered before calling register_kretprobe(), for giving a warning message and terminate registration process.
Signed-off-by: Wang ShaoBo <bobo.shaobowang@huawei.com> Signed-off-by: Cheng Jian <cj.chengjian@huawei.com> --- kernel/kprobes.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 41fdbb7953c6..7f54a70136f3 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -2117,6 +2117,14 @@ int register_kretprobe(struct kretprobe *rp) } } + /* + * Return error if it's being re-registered, + * also give a warning message to the developer. + */ + ret = check_kprobe_rereg(&rp->kp); + if (WARN_ON(ret)) + return ret; + rp->kp.pre_handler = pre_handler_kretprobe; rp->kp.post_handler = NULL; rp->kp.fault_handler = NULL; -- 2.17.1
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