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SubjectRe: [Memory Leak] free kprobe before optimized_kprobe free
(2012/08/24 2:05), akhilesh kumar wrote:
> From a77438899c7295299b59cdca8d1816ea69d6ed8e Mon Sep 17 00:00:00 2001
> From: Akhilesh Kumar <akhilesh.lxr@gmail.com>
> Date: Fri, 10 Aug 2012 14:02:07 +0530
> Subject:[Memory Leak] free kprobe before optimized_kprobe free
>
> Free *ap before *op otherwise ap pointer will be Dangling

Nack, since ap == op, this causes double free.

/*
* Internal structure for direct jump optimized probe
*/
struct optimized_kprobe {
struct kprobe kp;
struct list_head list; /* list for optimizing queue */
struct arch_optimized_insn optinsn;
};

Please look into alloc_aggr_kprobe() which allocates
optimized_kprobe, and returns op->kp.

Thank you,

>
> Signed-off-by: Akhilesh Kumar <akhilesh.lxr@gmail.com>
> ---
> kernel/kprobes.c | 1 +
> 1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index c62b854..ff0a97b 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -767,6 +767,7 @@ static __kprobes void
> try_to_optimize_kprobe(struct kprobe *p)
> if (!arch_prepared_optinsn(&op->optinsn)) {
> /* If failed to setup optimizing, fallback to kprobe */
> arch_remove_optimized_kprobe(op);
> + kfree(ap);
> kfree(op);
> return;
> }
>


--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com



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