From: Wang ShaoBo <bobo.shaobow...@huawei.com> 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.shaobow...@huawei.com Cc: sta...@vger.kernel.org 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....@linux.vnet.ibm.com> Acked-by: Ananth N Mavinakayanahalli <ana...@linux.ibm.com> Acked-by: Masami Hiramatsu <mhira...@kernel.org> Signed-off-by: Wang ShaoBo <bobo.shaobow...@huawei.com> Signed-off-by: Cheng Jian <cj.chengj...@huawei.com> Signed-off-by: Steven Rostedt (VMware) <rost...@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- kernel/kprobes.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1945,6 +1945,10 @@ int register_kretprobe(struct kretprobe 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))
