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 running register_kretprobe()'s body, for giving a warning message and terminate registration process. Signed-off-by: Wang ShaoBo <[email protected]> Signed-off-by: Cheng Jian <[email protected]> --- kernel/kprobes.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index f7fb5d135930..5c4a884953e9 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1978,6 +1978,10 @@ int register_kretprobe(struct kretprobe *rp) if (!kprobe_on_func_entry(rp->kp.addr, rp->kp.symbol_name, rp->kp.offset)) return -EINVAL; + /* If only rp->kp.addr is specified, check reregistering kprobes */ + if (rp->kp.addr && check_kprobe_rereg(&rp->kp)) + return -EINVAL; + if (kretprobe_blacklist_size) { addr = kprobe_addr(&rp->kp); if (IS_ERR(addr)) -- 2.25.1
