2015-07-01 19:30:11

by Anshul Garg

[permalink] [raw]
Subject: [PATCH] Sched/rt:Fix memory leak in alloc_rt_sched_group

From: Anshul Garg <[email protected]>

Added code to free allocated memory by function
alloc_rt_sched_group in case kzalloc api fails.

Signed-off-by: Anshul Garg <[email protected]>
---
kernel/sched/rt.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index f4d4b07..47213e9 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -177,7 +177,7 @@ int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
goto err;
tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL);
if (!tg->rt_se)
- goto err;
+ goto err_free_rt_rq;

init_rt_bandwidth(&tg->rt_bandwidth,
ktime_to_ns(def_rt_bandwidth.rt_period), 0);
@@ -186,7 +186,7 @@ int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
rt_rq = kzalloc_node(sizeof(struct rt_rq),
GFP_KERNEL, cpu_to_node(i));
if (!rt_rq)
- goto err;
+ goto err_free_rt_se;

rt_se = kzalloc_node(sizeof(struct sched_rt_entity),
GFP_KERNEL, cpu_to_node(i));
@@ -202,6 +202,10 @@ int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)

err_free_rq:
kfree(rt_rq);
+err_free_rt_se:
+ kfree(tg->rt_se);
+err_free_rt_rq:
+ kfree(tg->rt_rq);
err:
return 0;
}
--
1.7.9.5


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Subject: [tip:sched/core] sched/rt: Fix memory leak in alloc_rt_sched_group()

Commit-ID: ecdd6804b7c9e15fe8fc836ba0233d9912834e8b
Gitweb: http://git.kernel.org/tip/ecdd6804b7c9e15fe8fc836ba0233d9912834e8b
Author: Anshul Garg <[email protected]>
AuthorDate: Wed, 1 Jul 2015 12:29:26 -0700
Committer: Ingo Molnar <[email protected]>
CommitDate: Mon, 6 Jul 2015 14:17:14 +0200

sched/rt: Fix memory leak in alloc_rt_sched_group()

Added code to free allocated memory by function
alloc_rt_sched_group() in case the kzalloc() API fails.

Signed-off-by: Anshul Garg <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
kernel/sched/rt.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 0d193a24..cfa907d 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -193,7 +193,7 @@ int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
goto err;
tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL);
if (!tg->rt_se)
- goto err;
+ goto err_free_rt_rq;

init_rt_bandwidth(&tg->rt_bandwidth,
ktime_to_ns(def_rt_bandwidth.rt_period), 0);
@@ -202,7 +202,7 @@ int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
rt_rq = kzalloc_node(sizeof(struct rt_rq),
GFP_KERNEL, cpu_to_node(i));
if (!rt_rq)
- goto err;
+ goto err_free_rt_se;

rt_se = kzalloc_node(sizeof(struct sched_rt_entity),
GFP_KERNEL, cpu_to_node(i));
@@ -218,6 +218,10 @@ int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)

err_free_rq:
kfree(rt_rq);
+err_free_rt_se:
+ kfree(tg->rt_se);
+err_free_rt_rq:
+ kfree(tg->rt_rq);
err:
return 0;
}

2015-07-06 19:43:30

by Anshul Garg

[permalink] [raw]
Subject: Re: [tip:sched/core] sched/rt: Fix memory leak in alloc_rt_sched_group()

Dear linux community,

I think this patch" sched/rt: Fix memory leak in
alloc_rt_sched_group()" with Commit-ID:
ecdd6804b7c9e15fe8fc836ba0233d9912834e8b is not correct.

As it will create panic in case of kzalloc failure because of doingkfree twice.

As if alloc_rt_sched_group fails it will return zero then core.c will
call free_sched_group in core.c
which subsequently calls free_rt_sched_group .

In free_rt_sched_group memory is getting freed properly.

so it seems patch sent by me is not correct.

Please help to review patch once again as it might break some things.

Sorry for inconvenience.

Thanks
Anshul Garg

On Mon, Jul 6, 2015 at 9:05 PM, tip-bot for Anshul Garg
<[email protected]> wrote:
> Commit-ID: ecdd6804b7c9e15fe8fc836ba0233d9912834e8b
> Gitweb: http://git.kernel.org/tip/ecdd6804b7c9e15fe8fc836ba0233d9912834e8b
> Author: Anshul Garg <[email protected]>
> AuthorDate: Wed, 1 Jul 2015 12:29:26 -0700
> Committer: Ingo Molnar <[email protected]>
> CommitDate: Mon, 6 Jul 2015 14:17:14 +0200
>
> sched/rt: Fix memory leak in alloc_rt_sched_group()
>
> Added code to free allocated memory by function
> alloc_rt_sched_group() in case the kzalloc() API fails.
>
> Signed-off-by: Anshul Garg <[email protected]>
> Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
> Cc: Linus Torvalds <[email protected]>
> Cc: Peter Zijlstra <[email protected]>
> Cc: Thomas Gleixner <[email protected]>
> Link: http://lkml.kernel.org/r/[email protected]
> Signed-off-by: Ingo Molnar <[email protected]>
> ---
> kernel/sched/rt.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
> index 0d193a24..cfa907d 100644
> --- a/kernel/sched/rt.c
> +++ b/kernel/sched/rt.c
> @@ -193,7 +193,7 @@ int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
> goto err;
> tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL);
> if (!tg->rt_se)
> - goto err;
> + goto err_free_rt_rq;
>
> init_rt_bandwidth(&tg->rt_bandwidth,
> ktime_to_ns(def_rt_bandwidth.rt_period), 0);
> @@ -202,7 +202,7 @@ int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
> rt_rq = kzalloc_node(sizeof(struct rt_rq),
> GFP_KERNEL, cpu_to_node(i));
> if (!rt_rq)
> - goto err;
> + goto err_free_rt_se;
>
> rt_se = kzalloc_node(sizeof(struct sched_rt_entity),
> GFP_KERNEL, cpu_to_node(i));
> @@ -218,6 +218,10 @@ int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
>
> err_free_rq:
> kfree(rt_rq);
> +err_free_rt_se:
> + kfree(tg->rt_se);
> +err_free_rt_rq:
> + kfree(tg->rt_rq);
> err:
> return 0;
> }

2015-07-07 06:45:57

by Ingo Molnar

[permalink] [raw]
Subject: Re: [tip:sched/core] sched/rt: Fix memory leak in alloc_rt_sched_group()


* Anshul Garg <[email protected]> wrote:

> Dear linux community,
>
> I think this patch" sched/rt: Fix memory leak in
> alloc_rt_sched_group()" with Commit-ID:
> ecdd6804b7c9e15fe8fc836ba0233d9912834e8b is not correct.
>
> As it will create panic in case of kzalloc failure because of doingkfree twice.
>
> As if alloc_rt_sched_group fails it will return zero then core.c will
> call free_sched_group in core.c
> which subsequently calls free_rt_sched_group .
>
> In free_rt_sched_group memory is getting freed properly.
>
> so it seems patch sent by me is not correct.
>
> Please help to review patch once again as it might break some things.
>
> Sorry for inconvenience.
>
> Thanks
> Anshul Garg

Ok, I've removed this patch.

Thanks!

Ingo