[PATCH 5/6] ath6kl: Fix a debugfs crash for USB devices

[PATCH 5/6] ath6kl: Fix a debugfs crash for USB devices

[Mohammed Shafi Shajakhan]

From: Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com>

Credit distribution stats is currently implemented
only for SDIO. This fixes a crash in debugfs for
USB interface.

BUG: unable to handle kernel NULL pointer dereference at   (null)
IP: [<f91c2048>] read_file_credit_dist_stats+0x38/0x330 [ath6kl_core]
*pde = b62bd067
Oops: 0000 [#1] SMP

EIP: 0060:[<f91c2048>] EFLAGS: 00210246 CPU: 0
EIP is at read_file_credit_dist_stats+0x38/0x330 [ath6kl_core]
EAX: 00000000 EBX: e6f7a9c0 ECX: e7b148b8 EDX: 00000000
ESI: 000000c8 EDI: e7b14000 EBP: e6e09f64 ESP: e6e09f30
DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
Process cat (pid: 4058, ti=e6e08000 task=e50cf230 task.ti=e6e08000)
Stack:
00008000 00000000 e6e09f64 c1132d3c 00004e71 e50cf230 00008000 089e4000
e7b148b8 00000000 e6f7a9c0 00008000 089e4000 e6e09f8c c11331fc e6e09f98
00000001 e6e09f7c f91c2010 e6e09fac e6f7a9c0 089e4877 089e4000 e6e09fac

	Call Trace:
	[<c1132d3c>] ? rw_verify_area+0x6c/0x120
	[<c11331fc>] vfs_read+0x8c/0x160
	[<f91c2010>] ? read_file_war_stats+0x130/0x130 [ath6kl_core]
	[<c113330d>] sys_read+0x3d/0x70
	[<c15755b4>] syscall_call+0x7/0xb
	[<c1570000>] ? fill_powernow_table_pstate+0x127/0x127

Cc: Ryan Hsu <ryanhsu@qca.qualcomm.com>
Signed-off-by: Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com>
---
 drivers/net/wireless/ath/ath6kl/debug.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/wireless/ath/ath6kl/debug.c b/drivers/net/wireless/ath/ath6kl/debug.c
index 15cfe30..0dbb67b 100644
--- a/drivers/net/wireless/ath/ath6kl/debug.c
+++ b/drivers/net/wireless/ath/ath6kl/debug.c
@@ -658,6 +658,9 @@ static ssize_t read_file_credit_dist_stats(struct file *file,
 	unsigned int buf_len, len = 0;
 	ssize_t ret_cnt;
 
+	if (ar->hif_type != ATH6KL_HIF_TYPE_SDIO)
+		return -EINVAL;
+
 	buf_len = CREDIT_INFO_DISPLAY_STRING_LEN +
 		  get_queue_depth(&target->cred_dist_list) * CREDIT_INFO_LEN;
 	buf = kzalloc(buf_len, GFP_KERNEL);
-- 
1.7.9.5

Re: [PATCH 5/6] ath6kl: Fix a debugfs crash for USB devices

[Kalle Valo]

Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com> writes:

> From: Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com>
>
> Credit distribution stats is currently implemented
> only for SDIO. This fixes a crash in debugfs for
> USB interface.
>
> BUG: unable to handle kernel NULL pointer dereference at   (null)
> IP: [<f91c2048>] read_file_credit_dist_stats+0x38/0x330 [ath6kl_core]
> *pde = b62bd067
> Oops: 0000 [#1] SMP

[...]

> --- a/drivers/net/wireless/ath/ath6kl/debug.c
> +++ b/drivers/net/wireless/ath/ath6kl/debug.c
> @@ -658,6 +658,9 @@ static ssize_t read_file_credit_dist_stats(struct file *file,
>  	unsigned int buf_len, len = 0;
>  	ssize_t ret_cnt;
>  
> +	if (ar->hif_type != ATH6KL_HIF_TYPE_SDIO)
> +		return -EINVAL;

Actually I think it would be better not to even create the debugfs when
using sdio.

-- 
Kalle Valo

Re: [PATCH 5/6] ath6kl: Fix a debugfs crash for USB devices

[Mohammed Shafi Shajakhan]

Hi Kalle,

On 02/15/2013 04:00 PM, Kalle Valo wrote:
> Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com> writes:
>
>> From: Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com>
>>
>> Credit distribution stats is currently implemented
>> only for SDIO. This fixes a crash in debugfs for
>> USB interface.
>>
>> BUG: unable to handle kernel NULL pointer dereference at   (null)
>> IP: [<f91c2048>] read_file_credit_dist_stats+0x38/0x330 [ath6kl_core]
>> *pde = b62bd067
>> Oops: 0000 [#1] SMP
>
> [...]
>
>> --- a/drivers/net/wireless/ath/ath6kl/debug.c
>> +++ b/drivers/net/wireless/ath/ath6kl/debug.c
>> @@ -658,6 +658,9 @@ static ssize_t read_file_credit_dist_stats(struct file *file,
>>   	unsigned int buf_len, len = 0;
>>   	ssize_t ret_cnt;
>>
>> +	if (ar->hif_type != ATH6KL_HIF_TYPE_SDIO)
>> +		return -EINVAL;
>
> Actually I think it would be better not to even create the debugfs when
> using sdio.

agreed, but looks bit ugly right ? thoughts.

>


-- 
thanks,
shafi

Re: [PATCH 5/6] ath6kl: Fix a debugfs crash for USB devices

[Kalle Valo]

Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com> writes:

>>> +	if (ar->hif_type != ATH6KL_HIF_TYPE_SDIO)
>>> +		return -EINVAL;
>>
>> Actually I think it would be better not to even create the debugfs when
>> using sdio.

Oops, meant of course s/debugfs/debugfs file/. There seems to be packet
loss between my brains and fingers...

> agreed, but looks bit ugly right ? thoughts.

Sorry, but I don't understand how not creating the debugfs file for usb
would be ugly? But this isn't that important, if you want we can do it
like you propose as well.

-- 
Kalle Valo

Re: [PATCH 5/6] ath6kl: Fix a debugfs crash for USB devices

[Mohammed Shafi Shajakhan]

On 02/15/2013 05:13 PM, Kalle Valo wrote:
> Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com> writes:
>
>>>> +	if (ar->hif_type != ATH6KL_HIF_TYPE_SDIO)
>>>> +		return -EINVAL;
>>>
>>> Actually I think it would be better not to even create the debugfs when
>>> using sdio.
>
> Oops, meant of course s/debugfs/debugfs file/. There seems to be packet
> loss between my brains and fingers...

yeah I think its USB and debugfs file :)

>
>> agreed, but looks bit ugly right ? thoughts.
>
> Sorry, but I don't understand how not creating the debugfs file for usb
> would be ugly? But this isn't that important, if you want we can do it
> like you propose as well.
>

I will cook up a new patch, please see if that's fine :)

-- 
thanks,
shafi