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* [PATCH] ath9k: hif_usb: fix memory leak in ath9k_hif_usb_firmware_cb
@ 2021-07-09  8:43 Dongliang Mu
  2021-07-23 10:12 ` Dongliang Mu
                   ` (2 more replies)
  0 siblings, 3 replies; 5+ messages in thread
From: Dongliang Mu @ 2021-07-09  8:43 UTC (permalink / raw)
  To: ath9k-devel, Kalle Valo, David S. Miller, Jakub Kicinski, Brooke Basile
  Cc: Dongliang Mu, syzbot+6692c72009680f7c4eb2, linux-wireless,
	netdev, linux-kernel

The commit 03fb92a432ea ("ath9k: hif_usb: fix race condition between
usb_get_urb() and usb_kill_anchored_urbs()") adds three usb_get_urb
in ath9k_hif_usb_dealloc_tx_urbs and usb_free_urb.

Fix this bug by adding corresponding usb_free_urb in
ath9k_hif_usb_dealloc_tx_urbs other and hif_usb_stop.

Reported-by: syzbot+6692c72009680f7c4eb2@syzkaller.appspotmail.com
Fixes: 03fb92a432ea ("ath9k: hif_usb: fix race condition between usb_get_urb() and usb_kill_anchored_urbs()")
Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
---
 drivers/net/wireless/ath/ath9k/hif_usb.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/wireless/ath/ath9k/hif_usb.c b/drivers/net/wireless/ath/ath9k/hif_usb.c
index 860da13bfb6a..bda91ff3289b 100644
--- a/drivers/net/wireless/ath/ath9k/hif_usb.c
+++ b/drivers/net/wireless/ath/ath9k/hif_usb.c
@@ -457,6 +457,7 @@ static void hif_usb_stop(void *hif_handle)
 		usb_kill_urb(tx_buf->urb);
 		list_del(&tx_buf->list);
 		usb_free_urb(tx_buf->urb);
+		usb_free_urb(tx_buf->urb);
 		kfree(tx_buf->buf);
 		kfree(tx_buf);
 		spin_lock_irqsave(&hif_dev->tx.tx_lock, flags);
@@ -779,6 +780,7 @@ static void ath9k_hif_usb_dealloc_tx_urbs(struct hif_device_usb *hif_dev)
 		usb_kill_urb(tx_buf->urb);
 		list_del(&tx_buf->list);
 		usb_free_urb(tx_buf->urb);
+		usb_free_urb(tx_buf->urb);
 		kfree(tx_buf->buf);
 		kfree(tx_buf);
 		spin_lock_irqsave(&hif_dev->tx.tx_lock, flags);
@@ -797,6 +799,7 @@ static void ath9k_hif_usb_dealloc_tx_urbs(struct hif_device_usb *hif_dev)
 		usb_kill_urb(tx_buf->urb);
 		list_del(&tx_buf->list);
 		usb_free_urb(tx_buf->urb);
+		usb_free_urb(tx_buf->urb);
 		kfree(tx_buf->buf);
 		kfree(tx_buf);
 		spin_lock_irqsave(&hif_dev->tx.tx_lock, flags);
-- 
2.25.1


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] ath9k: hif_usb: fix memory leak in ath9k_hif_usb_firmware_cb
  2021-07-09  8:43 [PATCH] ath9k: hif_usb: fix memory leak in ath9k_hif_usb_firmware_cb Dongliang Mu
@ 2021-07-23 10:12 ` Dongliang Mu
  2021-07-27  6:02 ` Kalle Valo
  2021-07-27  7:24 ` Julian Calaby
  2 siblings, 0 replies; 5+ messages in thread
From: Dongliang Mu @ 2021-07-23 10:12 UTC (permalink / raw)
  To: ath9k-devel, Kalle Valo, David S. Miller, Jakub Kicinski, Brooke Basile
  Cc: syzbot+6692c72009680f7c4eb2, linux-wireless,
	open list:NETWORKING [GENERAL],
	linux-kernel

On Fri, Jul 9, 2021 at 4:44 PM Dongliang Mu <mudongliangabcd@gmail.com> wrote:
>
> The commit 03fb92a432ea ("ath9k: hif_usb: fix race condition between
> usb_get_urb() and usb_kill_anchored_urbs()") adds three usb_get_urb
> in ath9k_hif_usb_dealloc_tx_urbs and usb_free_urb.
>
> Fix this bug by adding corresponding usb_free_urb in
> ath9k_hif_usb_dealloc_tx_urbs other and hif_usb_stop.
>

Any idea about this patch?

> Reported-by: syzbot+6692c72009680f7c4eb2@syzkaller.appspotmail.com
> Fixes: 03fb92a432ea ("ath9k: hif_usb: fix race condition between usb_get_urb() and usb_kill_anchored_urbs()")
> Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
> ---
>  drivers/net/wireless/ath/ath9k/hif_usb.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/net/wireless/ath/ath9k/hif_usb.c b/drivers/net/wireless/ath/ath9k/hif_usb.c
> index 860da13bfb6a..bda91ff3289b 100644
> --- a/drivers/net/wireless/ath/ath9k/hif_usb.c
> +++ b/drivers/net/wireless/ath/ath9k/hif_usb.c
> @@ -457,6 +457,7 @@ static void hif_usb_stop(void *hif_handle)
>                 usb_kill_urb(tx_buf->urb);
>                 list_del(&tx_buf->list);
>                 usb_free_urb(tx_buf->urb);
> +               usb_free_urb(tx_buf->urb);
>                 kfree(tx_buf->buf);
>                 kfree(tx_buf);
>                 spin_lock_irqsave(&hif_dev->tx.tx_lock, flags);
> @@ -779,6 +780,7 @@ static void ath9k_hif_usb_dealloc_tx_urbs(struct hif_device_usb *hif_dev)
>                 usb_kill_urb(tx_buf->urb);
>                 list_del(&tx_buf->list);
>                 usb_free_urb(tx_buf->urb);
> +               usb_free_urb(tx_buf->urb);
>                 kfree(tx_buf->buf);
>                 kfree(tx_buf);
>                 spin_lock_irqsave(&hif_dev->tx.tx_lock, flags);
> @@ -797,6 +799,7 @@ static void ath9k_hif_usb_dealloc_tx_urbs(struct hif_device_usb *hif_dev)
>                 usb_kill_urb(tx_buf->urb);
>                 list_del(&tx_buf->list);
>                 usb_free_urb(tx_buf->urb);
> +               usb_free_urb(tx_buf->urb);
>                 kfree(tx_buf->buf);
>                 kfree(tx_buf);
>                 spin_lock_irqsave(&hif_dev->tx.tx_lock, flags);
> --
> 2.25.1
>

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] ath9k: hif_usb: fix memory leak in ath9k_hif_usb_firmware_cb
  2021-07-09  8:43 [PATCH] ath9k: hif_usb: fix memory leak in ath9k_hif_usb_firmware_cb Dongliang Mu
  2021-07-23 10:12 ` Dongliang Mu
@ 2021-07-27  6:02 ` Kalle Valo
  2021-07-27  7:24 ` Julian Calaby
  2 siblings, 0 replies; 5+ messages in thread
From: Kalle Valo @ 2021-07-27  6:02 UTC (permalink / raw)
  To: Dongliang Mu
  Cc: ath9k-devel, David S. Miller, Jakub Kicinski, Brooke Basile,
	syzbot+6692c72009680f7c4eb2, linux-wireless, netdev,
	linux-kernel

Dongliang Mu <mudongliangabcd@gmail.com> writes:

> The commit 03fb92a432ea ("ath9k: hif_usb: fix race condition between
> usb_get_urb() and usb_kill_anchored_urbs()") adds three usb_get_urb
> in ath9k_hif_usb_dealloc_tx_urbs and usb_free_urb.
>
> Fix this bug by adding corresponding usb_free_urb in
> ath9k_hif_usb_dealloc_tx_urbs other and hif_usb_stop.
>
> Reported-by: syzbot+6692c72009680f7c4eb2@syzkaller.appspotmail.com
> Fixes: 03fb92a432ea ("ath9k: hif_usb: fix race condition between usb_get_urb() and usb_kill_anchored_urbs()")
> Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>

In the past there have been so many problems with ath9k syzbot fixes
that I have now a hard time trusting them. Can someone review this in
detail, please?

-- 
https://patchwork.kernel.org/project/linux-wireless/list/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] ath9k: hif_usb: fix memory leak in ath9k_hif_usb_firmware_cb
  2021-07-09  8:43 [PATCH] ath9k: hif_usb: fix memory leak in ath9k_hif_usb_firmware_cb Dongliang Mu
  2021-07-23 10:12 ` Dongliang Mu
  2021-07-27  6:02 ` Kalle Valo
@ 2021-07-27  7:24 ` Julian Calaby
  2021-07-27 12:26   ` Kalle Valo
  2 siblings, 1 reply; 5+ messages in thread
From: Julian Calaby @ 2021-07-27  7:24 UTC (permalink / raw)
  To: Dongliang Mu
  Cc: QCA ath9k Development, Kalle Valo, David S. Miller,
	Jakub Kicinski, Brooke Basile, syzbot+6692c72009680f7c4eb2,
	linux-wireless, netdev, LKML

Hi Dongliang,

(Drive-by review, I know almost nothing about the code in question)

On Fri, Jul 9, 2021 at 6:47 PM Dongliang Mu <mudongliangabcd@gmail.com> wrote:
>
> The commit 03fb92a432ea ("ath9k: hif_usb: fix race condition between
> usb_get_urb() and usb_kill_anchored_urbs()") adds three usb_get_urb
> in ath9k_hif_usb_dealloc_tx_urbs and usb_free_urb.
>
> Fix this bug by adding corresponding usb_free_urb in
> ath9k_hif_usb_dealloc_tx_urbs other and hif_usb_stop.
>
> Reported-by: syzbot+6692c72009680f7c4eb2@syzkaller.appspotmail.com
> Fixes: 03fb92a432ea ("ath9k: hif_usb: fix race condition between usb_get_urb() and usb_kill_anchored_urbs()")
> Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
> ---
>  drivers/net/wireless/ath/ath9k/hif_usb.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/net/wireless/ath/ath9k/hif_usb.c b/drivers/net/wireless/ath/ath9k/hif_usb.c
> index 860da13bfb6a..bda91ff3289b 100644
> --- a/drivers/net/wireless/ath/ath9k/hif_usb.c
> +++ b/drivers/net/wireless/ath/ath9k/hif_usb.c
> @@ -457,6 +457,7 @@ static void hif_usb_stop(void *hif_handle)
>                 usb_kill_urb(tx_buf->urb);
>                 list_del(&tx_buf->list);
>                 usb_free_urb(tx_buf->urb);
> +               usb_free_urb(tx_buf->urb);

Ok, so if I'm reading this correctly, before the first usb_free_urb()
call, we have two references to the urb at tx_buf->urb.

Why?

Isn't the better fix here to detangle why there's more than one
reference to it and resolve it that way? This looks like a hack to fix
something much more fundamentally broken.

Thanks,

-- 
Julian Calaby

Email: julian.calaby@gmail.com
Profile: http://www.google.com/profiles/julian.calaby/

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] ath9k: hif_usb: fix memory leak in ath9k_hif_usb_firmware_cb
  2021-07-27  7:24 ` Julian Calaby
@ 2021-07-27 12:26   ` Kalle Valo
  0 siblings, 0 replies; 5+ messages in thread
From: Kalle Valo @ 2021-07-27 12:26 UTC (permalink / raw)
  To: Julian Calaby
  Cc: Dongliang Mu, QCA ath9k Development, David S. Miller,
	Jakub Kicinski, Brooke Basile, syzbot+6692c72009680f7c4eb2,
	linux-wireless, netdev, LKML

Julian Calaby <julian.calaby@gmail.com> writes:

> Hi Dongliang,
>
> (Drive-by review, I know almost nothing about the code in question)
>
> On Fri, Jul 9, 2021 at 6:47 PM Dongliang Mu <mudongliangabcd@gmail.com> wrote:
>>
>> The commit 03fb92a432ea ("ath9k: hif_usb: fix race condition between
>> usb_get_urb() and usb_kill_anchored_urbs()") adds three usb_get_urb
>> in ath9k_hif_usb_dealloc_tx_urbs and usb_free_urb.
>>
>> Fix this bug by adding corresponding usb_free_urb in
>> ath9k_hif_usb_dealloc_tx_urbs other and hif_usb_stop.
>>
>> Reported-by: syzbot+6692c72009680f7c4eb2@syzkaller.appspotmail.com
>> Fixes: 03fb92a432ea ("ath9k: hif_usb: fix race condition between usb_get_urb() and usb_kill_anchored_urbs()")
>> Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
>> ---
>>  drivers/net/wireless/ath/ath9k/hif_usb.c | 3 +++
>>  1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/net/wireless/ath/ath9k/hif_usb.c b/drivers/net/wireless/ath/ath9k/hif_usb.c
>> index 860da13bfb6a..bda91ff3289b 100644
>> --- a/drivers/net/wireless/ath/ath9k/hif_usb.c
>> +++ b/drivers/net/wireless/ath/ath9k/hif_usb.c
>> @@ -457,6 +457,7 @@ static void hif_usb_stop(void *hif_handle)
>>                 usb_kill_urb(tx_buf->urb);
>>                 list_del(&tx_buf->list);
>>                 usb_free_urb(tx_buf->urb);
>> +               usb_free_urb(tx_buf->urb);
>
> Ok, so if I'm reading this correctly, before the first usb_free_urb()
> call, we have two references to the urb at tx_buf->urb.
>
> Why?
>
> Isn't the better fix here to detangle why there's more than one
> reference to it and resolve it that way? This looks like a hack to fix
> something much more fundamentally broken.

Yeah, this looks very suspicious.

One more thing: also the patch should be tested with real hardware. I'm
worried that people are just trying to fix a syzbot warning and not
really considering how it works in real life. That's why I'm extra
careful with syzbot patches for wireless drivers.

-- 
https://patchwork.kernel.org/project/linux-wireless/list/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2021-07-27 12:26 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-07-09  8:43 [PATCH] ath9k: hif_usb: fix memory leak in ath9k_hif_usb_firmware_cb Dongliang Mu
2021-07-23 10:12 ` Dongliang Mu
2021-07-27  6:02 ` Kalle Valo
2021-07-27  7:24 ` Julian Calaby
2021-07-27 12:26   ` Kalle Valo

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