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SubjectRe: [PATCH 4/5] ath6kl/wmi.c: eliminate possible double free
Hi Julia,

On 10/21/2012 01:52 PM, Julia Lawall wrote:
> From: Julia Lawall <Julia.Lawall@lip6.fr>
>
> This makes two changes. In ath6kl_wmi_cmd_send, a call to dev_kfree_skb on
> the skb argument is added to the initial sanity check to more completely
> establish the invariant that ath6kl_wmi_cmd_send owns its skb argument.
> Then, in ath6kl_wmi_sync_point, on failure of the call to
> ath6kl_wmi_cmd_send, the clearing of the local skb variable is moved up, so
> that the error-handling code at the end of the function does not free it
> again.
>
> A simplified version of the semantic match that finds this problem is as
> follows: (http://coccinelle.lip6.fr/)
>
> // <smpl>
> @r@
> identifier f,free,a;
> parameter list[n] ps;
> type T;
> expression e;
> @@
>
> f(ps,T a,...) {
> ... when any
> when != a = e
> if(...) { ... free(a); ... return ...; }
> ... when any
> }
>
> @@
> identifier r.f,r.free;
> expression x,a;
> expression list[r.n] xs;
> @@
>
> * x = f(xs,a,...);
> if (...) { ... free(a); ... return ...; }
> // </smpl>
>
> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

I think this patch which is commited to ath6kl.git has fixed this.

commit 0616dc1f2bef563d7916c0dcedbb1bff7d9bd80b
Author: Vasanthakumar Thiagarajan <vthiagar@qca.qualcomm.com>
Date: Tue Aug 14 10:10:33 2012 +0530

ath6kl: Fix potential skb double free in ath6kl_wmi_sync_point()

skb given to ath6kl_control_tx() is owned by ath6kl_control_tx().
Calling function should not free the skb for error cases.
This is found during code review.

kvalo: fix a checkpatch warning in ath6kl_wmi_cmd_send()

Signed-off-by: Vasanthakumar Thiagarajan <vthiagar@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

https://github.com/kvalo/ath6kl/commit/0616dc1f2bef563d7916c0dcedbb1bff7d9bd80b

If you have the time, I would appreciate if you could take a look and
confirm.

Kalle


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