From: Wang ShaoBo <bobo.shaobowang@xxxxxxxxxx> commit 0188b87899ffc4a1d36a0badbe77d56c92fd91dc upstream. 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. Link: https://lkml.kernel.org/r/20210128124427.2031088-1-bobo.shaobowang@xxxxxxxxxx Cc: stable@xxxxxxxxxxxxxxx Fixes: 1f0ab40976460 ("kprobes: Prevent re-registration of the same kprobe") [ The above commit should have been done for kretprobes too ] Acked-by: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx> Acked-by: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxxxxx> Acked-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx> Signed-off-by: Wang ShaoBo <bobo.shaobowang@xxxxxxxxxx> Signed-off-by: Cheng Jian <cj.chengjian@xxxxxxxxxx> Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/kprobes.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1884,6 +1884,10 @@ int register_kretprobe(struct kretprobe int i; void *addr; + /* 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))
