Messages in this thread |  | | Date | Fri, 18 Dec 2015 06:55:34 -0800 | From | Davidlohr Bueso <> | Subject | Re: [PATCH] futex: Prevent pi_state from double freeing in case of error |
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On Fri, 18 Dec 2015, Bhuvanesh_Surachari@mentor.com wrote:
>From: Bhuvanesh Surachari <bhuvanesh_surachari@mentor.com> > >In case of error from rt_mutex_start_proxy_lock pi_state is freed >twice in futex_requeue function. Hence removing free_pi_state in >else branch and branching to the location where pi_state is freed.
This reads weird.
Do note that free_pi_state is already protected against passing it a nil pi_state, so this is merely cosmetic.
Hmm but yeah, looks legit. The cases were we free the pi_state on error are when doing retry kind of paths, EDEADLK not being one of those cases.
> >Signed-off-by: Bhuvanesh Surachari <Bhuvanesh_Surachari@mentor.com> >Signed-off-by: Andy Lowe <Andy_Lowe@mentor.com>
This last SoB tag is incorrect, Andy Lowe is not carrying the patch for you.
>--- > kernel/futex.c | 1 - > 1 file changed, 1 deletion(-) > >diff --git a/kernel/futex.c b/kernel/futex.c >index 684d754..264b3f2 100644 >--- a/kernel/futex.c >+++ b/kernel/futex.c >@@ -1815,7 +1815,6 @@ retry_private: > } else if (ret) { > /* -EDEADLK */ > this->pi_state = NULL; >- free_pi_state(pi_state); > goto out_unlock; > } > }
Nit but I think we also want to set pi_state to nil after freeing it in out_unlock. That way this scenario would simply be goto out_unlock.
Thanks, Davidlohr
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