* [PATCH] kexec: fix memory leak in function kimage_normal_alloc
@ 2013-02-22 4:36 Zhang Yanfei
2013-02-22 21:59 ` Andrew Morton
2013-02-22 22:54 ` Simon Horman
0 siblings, 2 replies; 4+ messages in thread
From: Zhang Yanfei @ 2013-02-22 4:36 UTC (permalink / raw)
To: Eric W. Biederman
Cc: Sasha Levin, Andrew Morton, kexec@lists.infradead.org,
linux-kernel@vger.kernel.org
If kimage_normal_alloc() fails to alloc pages for image->swap_page, it
should call kimage_free_page_list() to free allocated pages in
image->control_pages list before it frees image.
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
---
kernel/kexec.c | 18 ++++++++++--------
1 files changed, 10 insertions(+), 8 deletions(-)
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 5e4bd78..a57face 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -223,6 +223,8 @@ out:
}
+static void kimage_free_page_list(struct list_head *list);
+
static int kimage_normal_alloc(struct kimage **rimage, unsigned long entry,
unsigned long nr_segments,
struct kexec_segment __user *segments)
@@ -248,22 +250,22 @@ static int kimage_normal_alloc(struct kimage **rimage, unsigned long entry,
get_order(KEXEC_CONTROL_PAGE_SIZE));
if (!image->control_code_page) {
printk(KERN_ERR "Could not allocate control_code_buffer\n");
- goto out;
+ goto out_free;
}
image->swap_page = kimage_alloc_control_pages(image, 0);
if (!image->swap_page) {
printk(KERN_ERR "Could not allocate swap buffer\n");
- goto out;
+ goto out_free;
}
- result = 0;
- out:
- if (result == 0)
- *rimage = image;
- else
- kfree(image);
+ *rimage = image;
+ return 0;
+out_free:
+ kimage_free_page_list(&image->control_pages);
+ kfree(image);
+out:
return result;
}
--
1.7.1
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http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] kexec: fix memory leak in function kimage_normal_alloc
2013-02-22 4:36 [PATCH] kexec: fix memory leak in function kimage_normal_alloc Zhang Yanfei
@ 2013-02-22 21:59 ` Andrew Morton
2013-02-23 13:48 ` Yanfei Zhang
2013-02-22 22:54 ` Simon Horman
1 sibling, 1 reply; 4+ messages in thread
From: Andrew Morton @ 2013-02-22 21:59 UTC (permalink / raw)
To: Zhang Yanfei
Cc: Sasha Levin, kexec@lists.infradead.org, Eric W. Biederman,
linux-kernel@vger.kernel.org
On Fri, 22 Feb 2013 12:36:13 +0800
Zhang Yanfei <zhangyanfei@cn.fujitsu.com> wrote:
> If kimage_normal_alloc() fails to alloc pages for image->swap_page, it
> should call kimage_free_page_list() to free allocated pages in
> image->control_pages list before it frees image.
>
> ...
>
> --- a/kernel/kexec.c
> +++ b/kernel/kexec.c
> @@ -223,6 +223,8 @@ out:
>
> }
>
> +static void kimage_free_page_list(struct list_head *list);
> +
> static int kimage_normal_alloc(struct kimage **rimage, unsigned long entry,
> unsigned long nr_segments,
> struct kexec_segment __user *segments)
> @@ -248,22 +250,22 @@ static int kimage_normal_alloc(struct kimage **rimage, unsigned long entry,
> get_order(KEXEC_CONTROL_PAGE_SIZE));
> if (!image->control_code_page) {
> printk(KERN_ERR "Could not allocate control_code_buffer\n");
> - goto out;
> + goto out_free;
> }
>
> image->swap_page = kimage_alloc_control_pages(image, 0);
> if (!image->swap_page) {
> printk(KERN_ERR "Could not allocate swap buffer\n");
> - goto out;
> + goto out_free;
> }
>
> - result = 0;
> - out:
> - if (result == 0)
> - *rimage = image;
> - else
> - kfree(image);
> + *rimage = image;
> + return 0;
>
> +out_free:
> + kimage_free_page_list(&image->control_pages);
> + kfree(image);
> +out:
> return result;
> }
kimage_alloc_normal_control_pages() won't add any pages to the image if
one of its allocation attemtps failed. So afaict the first `goto
out_free' could be just `goto out'.
The second `goto out_free' does appear to be needed: it frees the pages
allocated by the first call to kimage_alloc_control_pages(). I think.
The kimage_alloc_control_pages() handling of image->type is a bit
twisty.
Please double-check the logic?
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^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] kexec: fix memory leak in function kimage_normal_alloc
2013-02-22 21:59 ` Andrew Morton
@ 2013-02-23 13:48 ` Yanfei Zhang
0 siblings, 0 replies; 4+ messages in thread
From: Yanfei Zhang @ 2013-02-23 13:48 UTC (permalink / raw)
To: Andrew Morton
Cc: Sasha Levin, Zhang Yanfei, Eric W. Biederman,
linux-kernel@vger.kernel.org, kexec@lists.infradead.org
2013/2/23 Andrew Morton <akpm@linux-foundation.org>:
> On Fri, 22 Feb 2013 12:36:13 +0800
> Zhang Yanfei <zhangyanfei@cn.fujitsu.com> wrote:
>
>> If kimage_normal_alloc() fails to alloc pages for image->swap_page, it
>> should call kimage_free_page_list() to free allocated pages in
>> image->control_pages list before it frees image.
>>
>> ...
>>
>> --- a/kernel/kexec.c
>> +++ b/kernel/kexec.c
>> @@ -223,6 +223,8 @@ out:
>>
>> }
>>
>> +static void kimage_free_page_list(struct list_head *list);
>> +
>> static int kimage_normal_alloc(struct kimage **rimage, unsigned long entry,
>> unsigned long nr_segments,
>> struct kexec_segment __user *segments)
>> @@ -248,22 +250,22 @@ static int kimage_normal_alloc(struct kimage **rimage, unsigned long entry,
>> get_order(KEXEC_CONTROL_PAGE_SIZE));
>> if (!image->control_code_page) {
>> printk(KERN_ERR "Could not allocate control_code_buffer\n");
>> - goto out;
>> + goto out_free;
>> }
>>
>> image->swap_page = kimage_alloc_control_pages(image, 0);
>> if (!image->swap_page) {
>> printk(KERN_ERR "Could not allocate swap buffer\n");
>> - goto out;
>> + goto out_free;
>> }
>>
>> - result = 0;
>> - out:
>> - if (result == 0)
>> - *rimage = image;
>> - else
>> - kfree(image);
>> + *rimage = image;
>> + return 0;
>>
>> +out_free:
>> + kimage_free_page_list(&image->control_pages);
>> + kfree(image);
>> +out:
>> return result;
>> }
>
> kimage_alloc_normal_control_pages() won't add any pages to the image if
> one of its allocation attemtps failed. So afaict the first `goto
> out_free' could be just `goto out'.
Nop, the first 'goto out_free' is to free allocated 'image' if the allocation of
image->control_code_page failed. If changed to 'goto out', 'image' cannot
be freed and leads to memory leak.
>
> The second `goto out_free' does appear to be needed: it frees the pages
> allocated by the first call to kimage_alloc_control_pages(). I think.
> The kimage_alloc_control_pages() handling of image->type is a bit
> twisty.
Yeah, it could just call kimage_alloc_normal_control_pages directly.
>
> Please double-check the logic?
> --
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] kexec: fix memory leak in function kimage_normal_alloc
2013-02-22 4:36 [PATCH] kexec: fix memory leak in function kimage_normal_alloc Zhang Yanfei
2013-02-22 21:59 ` Andrew Morton
@ 2013-02-22 22:54 ` Simon Horman
1 sibling, 0 replies; 4+ messages in thread
From: Simon Horman @ 2013-02-22 22:54 UTC (permalink / raw)
To: Zhang Yanfei
Cc: Sasha Levin, Andrew Morton, kexec@lists.infradead.org,
Eric W. Biederman, linux-kernel@vger.kernel.org
On Fri, Feb 22, 2013 at 12:36:13PM +0800, Zhang Yanfei wrote:
> If kimage_normal_alloc() fails to alloc pages for image->swap_page, it
> should call kimage_free_page_list() to free allocated pages in
> image->control_pages list before it frees image.
>
> Cc: "Eric W. Biederman" <ebiederm@xmission.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Sasha Levin <sasha.levin@oracle.com>
> Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Reviewed-by: Simon Horman <horms@verge.net.au>
> ---
> kernel/kexec.c | 18 ++++++++++--------
> 1 files changed, 10 insertions(+), 8 deletions(-)
>
> diff --git a/kernel/kexec.c b/kernel/kexec.c
> index 5e4bd78..a57face 100644
> --- a/kernel/kexec.c
> +++ b/kernel/kexec.c
> @@ -223,6 +223,8 @@ out:
>
> }
>
> +static void kimage_free_page_list(struct list_head *list);
> +
> static int kimage_normal_alloc(struct kimage **rimage, unsigned long entry,
> unsigned long nr_segments,
> struct kexec_segment __user *segments)
> @@ -248,22 +250,22 @@ static int kimage_normal_alloc(struct kimage **rimage, unsigned long entry,
> get_order(KEXEC_CONTROL_PAGE_SIZE));
> if (!image->control_code_page) {
> printk(KERN_ERR "Could not allocate control_code_buffer\n");
> - goto out;
> + goto out_free;
> }
>
> image->swap_page = kimage_alloc_control_pages(image, 0);
> if (!image->swap_page) {
> printk(KERN_ERR "Could not allocate swap buffer\n");
> - goto out;
> + goto out_free;
> }
>
> - result = 0;
> - out:
> - if (result == 0)
> - *rimage = image;
> - else
> - kfree(image);
> + *rimage = image;
> + return 0;
>
> +out_free:
> + kimage_free_page_list(&image->control_pages);
> + kfree(image);
> +out:
> return result;
> }
>
> --
> 1.7.1
>
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec
>
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^ permalink raw reply [flat|nested] 4+ messages in thread
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2013-02-22 4:36 [PATCH] kexec: fix memory leak in function kimage_normal_alloc Zhang Yanfei
2013-02-22 21:59 ` Andrew Morton
2013-02-23 13:48 ` Yanfei Zhang
2013-02-22 22:54 ` Simon Horman
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