LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
* [PATCH] usb: storage: add error handling for kcalloc
@ 2018-06-11  8:52 Zhouyang Jia
  2018-06-12 14:31 ` Alan Stern
  2018-06-14 13:29 ` [PATCH v2] " Zhouyang Jia
  0 siblings, 2 replies; 7+ messages in thread
From: Zhouyang Jia @ 2018-06-11  8:52 UTC (permalink / raw)
  Cc: Zhouyang Jia, Alan Stern, Greg Kroah-Hartman, linux-usb,
	usb-storage, linux-kernel

When kcalloc fails, the lack of error-handling code may
cause unexpected results.

This patch adds error-handling code after calling kcalloc.

Signed-off-by: Zhouyang Jia <jiazhouyang09@gmail.com>
---
 drivers/usb/storage/alauda.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/usb/storage/alauda.c b/drivers/usb/storage/alauda.c
index 900591d..c56355c 100644
--- a/drivers/usb/storage/alauda.c
+++ b/drivers/usb/storage/alauda.c
@@ -437,6 +437,11 @@ static int alauda_init_media(struct us_data *us)
 		+ MEDIA_INFO(us).blockshift + MEDIA_INFO(us).pageshift);
 	MEDIA_INFO(us).pba_to_lba = kcalloc(num_zones, sizeof(u16*), GFP_NOIO);
 	MEDIA_INFO(us).lba_to_pba = kcalloc(num_zones, sizeof(u16*), GFP_NOIO);
+	if ((MEDIA_INFO(us).pba_to_lba == NULL)
+		|| (MEDIA_INFO(us).lba_to_pba == NULL)) {
+		pr_warn("alauda_init_media: memory allocation failed\n");
+		return USB_STOR_TRANSPORT_ERROR;
+	}
 
 	if (alauda_reset_media(us) != USB_STOR_XFER_GOOD)
 		return USB_STOR_TRANSPORT_ERROR;
-- 
2.7.4

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [PATCH] usb: storage: add error handling for kcalloc
  2018-06-11  8:52 [PATCH] usb: storage: add error handling for kcalloc Zhouyang Jia
@ 2018-06-12 14:31 ` Alan Stern
  2018-06-14 13:29 ` [PATCH v2] " Zhouyang Jia
  1 sibling, 0 replies; 7+ messages in thread
From: Alan Stern @ 2018-06-12 14:31 UTC (permalink / raw)
  To: Zhouyang Jia; +Cc: Greg Kroah-Hartman, linux-usb, usb-storage, linux-kernel

On Mon, 11 Jun 2018, Zhouyang Jia wrote:

> When kcalloc fails, the lack of error-handling code may
> cause unexpected results.
> 
> This patch adds error-handling code after calling kcalloc.
> 
> Signed-off-by: Zhouyang Jia <jiazhouyang09@gmail.com>
> ---
>  drivers/usb/storage/alauda.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/usb/storage/alauda.c b/drivers/usb/storage/alauda.c
> index 900591d..c56355c 100644
> --- a/drivers/usb/storage/alauda.c
> +++ b/drivers/usb/storage/alauda.c
> @@ -437,6 +437,11 @@ static int alauda_init_media(struct us_data *us)
>  		+ MEDIA_INFO(us).blockshift + MEDIA_INFO(us).pageshift);
>  	MEDIA_INFO(us).pba_to_lba = kcalloc(num_zones, sizeof(u16*), GFP_NOIO);
>  	MEDIA_INFO(us).lba_to_pba = kcalloc(num_zones, sizeof(u16*), GFP_NOIO);
> +	if ((MEDIA_INFO(us).pba_to_lba == NULL)
> +		|| (MEDIA_INFO(us).lba_to_pba == NULL)) {
> +		pr_warn("alauda_init_media: memory allocation failed\n");
> +		return USB_STOR_TRANSPORT_ERROR;
> +	}

pr_info() isn't a good routine to use here, because it doesn't print 
the device or driver name.

In any case, a log message isn't necessary.  kcalloc() will already 
put a message in the log if either of the allocations fails.

Alan Stern

>  
>  	if (alauda_reset_media(us) != USB_STOR_XFER_GOOD)
>  		return USB_STOR_TRANSPORT_ERROR;
> 


^ permalink raw reply	[flat|nested] 7+ messages in thread

* [PATCH v2] usb: storage: add error handling for kcalloc
  2018-06-11  8:52 [PATCH] usb: storage: add error handling for kcalloc Zhouyang Jia
  2018-06-12 14:31 ` Alan Stern
@ 2018-06-14 13:29 ` Zhouyang Jia
  2018-06-14 14:58   ` Alan Stern
  2018-06-25 12:33   ` Greg Kroah-Hartman
  1 sibling, 2 replies; 7+ messages in thread
From: Zhouyang Jia @ 2018-06-14 13:29 UTC (permalink / raw)
  Cc: Zhouyang Jia, Alan Stern, Greg Kroah-Hartman, linux-usb,
	usb-storage, linux-kernel

When kcalloc fails, the lack of error-handling code may
cause unexpected results.

This patch adds error-handling code after calling kcalloc.

Signed-off-by: Zhouyang Jia <jiazhouyang09@gmail.com>
---
v1->v2:
- Remove pr_warn statement.
---
 drivers/usb/storage/alauda.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/storage/alauda.c b/drivers/usb/storage/alauda.c
index 900591d..4e17609 100644
--- a/drivers/usb/storage/alauda.c
+++ b/drivers/usb/storage/alauda.c
@@ -437,6 +437,9 @@ static int alauda_init_media(struct us_data *us)
 		+ MEDIA_INFO(us).blockshift + MEDIA_INFO(us).pageshift);
 	MEDIA_INFO(us).pba_to_lba = kcalloc(num_zones, sizeof(u16*), GFP_NOIO);
 	MEDIA_INFO(us).lba_to_pba = kcalloc(num_zones, sizeof(u16*), GFP_NOIO);
+	if ((MEDIA_INFO(us).pba_to_lba == NULL)
+		|| (MEDIA_INFO(us).lba_to_pba == NULL))
+		return USB_STOR_TRANSPORT_ERROR;
 
 	if (alauda_reset_media(us) != USB_STOR_XFER_GOOD)
 		return USB_STOR_TRANSPORT_ERROR;
-- 
2.7.4


^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [PATCH v2] usb: storage: add error handling for kcalloc
  2018-06-14 13:29 ` [PATCH v2] " Zhouyang Jia
@ 2018-06-14 14:58   ` Alan Stern
  2018-06-25 12:33   ` Greg Kroah-Hartman
  1 sibling, 0 replies; 7+ messages in thread
From: Alan Stern @ 2018-06-14 14:58 UTC (permalink / raw)
  To: Zhouyang Jia; +Cc: Greg Kroah-Hartman, linux-usb, usb-storage, linux-kernel

On Thu, 14 Jun 2018, Zhouyang Jia wrote:

> When kcalloc fails, the lack of error-handling code may
> cause unexpected results.
> 
> This patch adds error-handling code after calling kcalloc.
> 
> Signed-off-by: Zhouyang Jia <jiazhouyang09@gmail.com>
> ---
> v1->v2:
> - Remove pr_warn statement.
> ---
>  drivers/usb/storage/alauda.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/usb/storage/alauda.c b/drivers/usb/storage/alauda.c
> index 900591d..4e17609 100644
> --- a/drivers/usb/storage/alauda.c
> +++ b/drivers/usb/storage/alauda.c
> @@ -437,6 +437,9 @@ static int alauda_init_media(struct us_data *us)
>  		+ MEDIA_INFO(us).blockshift + MEDIA_INFO(us).pageshift);
>  	MEDIA_INFO(us).pba_to_lba = kcalloc(num_zones, sizeof(u16*), GFP_NOIO);
>  	MEDIA_INFO(us).lba_to_pba = kcalloc(num_zones, sizeof(u16*), GFP_NOIO);
> +	if ((MEDIA_INFO(us).pba_to_lba == NULL)
> +		|| (MEDIA_INFO(us).lba_to_pba == NULL))
> +		return USB_STOR_TRANSPORT_ERROR;
>  
>  	if (alauda_reset_media(us) != USB_STOR_XFER_GOOD)
>  		return USB_STOR_TRANSPORT_ERROR;
> 

Acked-by: Alan Stern <stern@rowland.harvard.edu>


^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [PATCH v2] usb: storage: add error handling for kcalloc
  2018-06-14 13:29 ` [PATCH v2] " Zhouyang Jia
  2018-06-14 14:58   ` Alan Stern
@ 2018-06-25 12:33   ` Greg Kroah-Hartman
  2018-06-25 15:22     ` Alan Stern
  1 sibling, 1 reply; 7+ messages in thread
From: Greg Kroah-Hartman @ 2018-06-25 12:33 UTC (permalink / raw)
  To: Zhouyang Jia; +Cc: Alan Stern, linux-usb, usb-storage, linux-kernel

On Thu, Jun 14, 2018 at 09:29:11PM +0800, Zhouyang Jia wrote:
> When kcalloc fails, the lack of error-handling code may
> cause unexpected results.
> 
> This patch adds error-handling code after calling kcalloc.
> 
> Signed-off-by: Zhouyang Jia <jiazhouyang09@gmail.com>
> Acked-by: Alan Stern <stern@rowland.harvard.edu>
> ---
> v1->v2:
> - Remove pr_warn statement.
> ---
>  drivers/usb/storage/alauda.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/usb/storage/alauda.c b/drivers/usb/storage/alauda.c
> index 900591d..4e17609 100644
> --- a/drivers/usb/storage/alauda.c
> +++ b/drivers/usb/storage/alauda.c
> @@ -437,6 +437,9 @@ static int alauda_init_media(struct us_data *us)
>  		+ MEDIA_INFO(us).blockshift + MEDIA_INFO(us).pageshift);
>  	MEDIA_INFO(us).pba_to_lba = kcalloc(num_zones, sizeof(u16*), GFP_NOIO);
>  	MEDIA_INFO(us).lba_to_pba = kcalloc(num_zones, sizeof(u16*), GFP_NOIO);
> +	if ((MEDIA_INFO(us).pba_to_lba == NULL)
> +		|| (MEDIA_INFO(us).lba_to_pba == NULL))
> +		return USB_STOR_TRANSPORT_ERROR;

You just leaked memory if only one of these succeeded :(

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [PATCH v2] usb: storage: add error handling for kcalloc
  2018-06-25 12:33   ` Greg Kroah-Hartman
@ 2018-06-25 15:22     ` Alan Stern
  2018-06-28 10:52       ` Greg Kroah-Hartman
  0 siblings, 1 reply; 7+ messages in thread
From: Alan Stern @ 2018-06-25 15:22 UTC (permalink / raw)
  To: Greg Kroah-Hartman; +Cc: Zhouyang Jia, linux-usb, usb-storage, linux-kernel

On Mon, 25 Jun 2018, Greg Kroah-Hartman wrote:

> On Thu, Jun 14, 2018 at 09:29:11PM +0800, Zhouyang Jia wrote:
> > When kcalloc fails, the lack of error-handling code may
> > cause unexpected results.
> > 
> > This patch adds error-handling code after calling kcalloc.
> > 
> > Signed-off-by: Zhouyang Jia <jiazhouyang09@gmail.com>
> > Acked-by: Alan Stern <stern@rowland.harvard.edu>
> > ---
> > v1->v2:
> > - Remove pr_warn statement.
> > ---
> >  drivers/usb/storage/alauda.c | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/drivers/usb/storage/alauda.c b/drivers/usb/storage/alauda.c
> > index 900591d..4e17609 100644
> > --- a/drivers/usb/storage/alauda.c
> > +++ b/drivers/usb/storage/alauda.c
> > @@ -437,6 +437,9 @@ static int alauda_init_media(struct us_data *us)
> >  		+ MEDIA_INFO(us).blockshift + MEDIA_INFO(us).pageshift);
> >  	MEDIA_INFO(us).pba_to_lba = kcalloc(num_zones, sizeof(u16*), GFP_NOIO);
> >  	MEDIA_INFO(us).lba_to_pba = kcalloc(num_zones, sizeof(u16*), GFP_NOIO);
> > +	if ((MEDIA_INFO(us).pba_to_lba == NULL)
> > +		|| (MEDIA_INFO(us).lba_to_pba == NULL))
> > +		return USB_STOR_TRANSPORT_ERROR;
> 
> You just leaked memory if only one of these succeeded :(

That's not really true.  The memory gets deallocated later on in any 
case, when alauda_info_destructor() calls alauda_free_maps() if not 
before.

More troubling is the fact that this routine (i.e, alauda_init_media)  
gets called from only one place, in alauda_check_media, and the caller
completely ignores the return value!  Furthermore, the caller always
returns USB_STOR_TRANSPORT_FAILED.

So on the whole, I don't think this patch is going to make any 
difference to the driver's operation.

Alan Stern


^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [PATCH v2] usb: storage: add error handling for kcalloc
  2018-06-25 15:22     ` Alan Stern
@ 2018-06-28 10:52       ` Greg Kroah-Hartman
  0 siblings, 0 replies; 7+ messages in thread
From: Greg Kroah-Hartman @ 2018-06-28 10:52 UTC (permalink / raw)
  To: Alan Stern; +Cc: Zhouyang Jia, linux-usb, usb-storage, linux-kernel

On Mon, Jun 25, 2018 at 11:22:34AM -0400, Alan Stern wrote:
> On Mon, 25 Jun 2018, Greg Kroah-Hartman wrote:
> 
> > On Thu, Jun 14, 2018 at 09:29:11PM +0800, Zhouyang Jia wrote:
> > > When kcalloc fails, the lack of error-handling code may
> > > cause unexpected results.
> > > 
> > > This patch adds error-handling code after calling kcalloc.
> > > 
> > > Signed-off-by: Zhouyang Jia <jiazhouyang09@gmail.com>
> > > Acked-by: Alan Stern <stern@rowland.harvard.edu>
> > > ---
> > > v1->v2:
> > > - Remove pr_warn statement.
> > > ---
> > >  drivers/usb/storage/alauda.c | 3 +++
> > >  1 file changed, 3 insertions(+)
> > > 
> > > diff --git a/drivers/usb/storage/alauda.c b/drivers/usb/storage/alauda.c
> > > index 900591d..4e17609 100644
> > > --- a/drivers/usb/storage/alauda.c
> > > +++ b/drivers/usb/storage/alauda.c
> > > @@ -437,6 +437,9 @@ static int alauda_init_media(struct us_data *us)
> > >  		+ MEDIA_INFO(us).blockshift + MEDIA_INFO(us).pageshift);
> > >  	MEDIA_INFO(us).pba_to_lba = kcalloc(num_zones, sizeof(u16*), GFP_NOIO);
> > >  	MEDIA_INFO(us).lba_to_pba = kcalloc(num_zones, sizeof(u16*), GFP_NOIO);
> > > +	if ((MEDIA_INFO(us).pba_to_lba == NULL)
> > > +		|| (MEDIA_INFO(us).lba_to_pba == NULL))
> > > +		return USB_STOR_TRANSPORT_ERROR;
> > 
> > You just leaked memory if only one of these succeeded :(
> 
> That's not really true.  The memory gets deallocated later on in any 
> case, when alauda_info_destructor() calls alauda_free_maps() if not 
> before.
> 
> More troubling is the fact that this routine (i.e, alauda_init_media)  
> gets called from only one place, in alauda_check_media, and the caller
> completely ignores the return value!  Furthermore, the caller always
> returns USB_STOR_TRANSPORT_FAILED.
> 
> So on the whole, I don't think this patch is going to make any 
> difference to the driver's operation.

Ok, I'm just going to drop it then.

thanks,

greg k-h

^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2018-06-28 11:01 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-06-11  8:52 [PATCH] usb: storage: add error handling for kcalloc Zhouyang Jia
2018-06-12 14:31 ` Alan Stern
2018-06-14 13:29 ` [PATCH v2] " Zhouyang Jia
2018-06-14 14:58   ` Alan Stern
2018-06-25 12:33   ` Greg Kroah-Hartman
2018-06-25 15:22     ` Alan Stern
2018-06-28 10:52       ` Greg Kroah-Hartman

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).