On Tue, 24 Oct 2017 20:17:02 +0800
JianKang Chen <chenjianka...@huawei.com> wrote:
> The function register_kretprobe is used to initialize a struct
> kretprobe and allocate a list table for kprobe instance.
> However,in this function, there is a memory leak.
>
> The test case:
>
> static struct kretprobe rp;
> struct kretprobe *rps[10]={&rp ,&rp ,&rp ,
> &rp ,&rp ,&rp ,&rp ,&rp ,&rp,&rp};
What ? this is buggy code. you must not list same kretprobe.
But, year, since register_kprobe() already has similar protection against
reusing, register_kretprobe() should do so.
[..]
> raw_spin_lock_init(&rp->lock);
> +
> + if (!hlist_empty(&rp->free_instances))
> + return -EBUSY;
> +
Hmm, but can you use check_kprobe_rereg() before raw_spin_lock_init()?
If user reuses rp after it starts, rp->lock can already be used.
Thank you,
> INIT_HLIST_HEAD(&rp->free_instances);
> for (i = 0; i < rp->maxactive; i++) {
> inst = kmalloc(sizeof(struct kretprobe_instance) +
> --
> 1.7.12.4
>
--
Masami Hiramatsu <mhira...@kernel.org>
