linux-kernel - Re: [PATCH 1/2] drivers: staging: wilc1000: Move spin lock to the start of critical section

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <5611ED46.7040800@atmel.com>
Date:	Mon, 5 Oct 2015 12:23:50 +0900
From:	Tony Cho <tony.cho@...el.com>
To:	Greg KH <gregkh@...uxfoundation.org>,
	Chandra S Gorentla <csgorentla@...il.com>
CC:	<rachel.kim@...el.com>, <devel@...verdev.osuosl.org>,
	<chris.park@...el.com>, <linux-wireless@...r.kernel.org>,
	<johnny.kim@...el.com>, <linux-kernel@...r.kernel.org>,
	<dan.carpenter@...cle.com>
Subject: Re: [PATCH 1/2] drivers: staging: wilc1000: Move spin lock to the
 start of critical section



On 2015년 10월 04일 17:43, Greg KH wrote:
> On Sat, Oct 03, 2015 at 02:57:29PM +0530, Chandra S Gorentla wrote:
>> The spin_lock_irqsave is moved to just beginning of critical section.
>> This change moves a couple of return statements out of the lock.
>>
>> Signed-off-by: Chandra S Gorentla <csgorentla@...il.com>
>> ---
>>   drivers/staging/wilc1000/wilc_msgqueue.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/staging/wilc1000/wilc_msgqueue.c b/drivers/staging/wilc1000/wilc_msgqueue.c
>> index d5ebd6d..284a3f5 100644
>> --- a/drivers/staging/wilc1000/wilc_msgqueue.c
>> +++ b/drivers/staging/wilc1000/wilc_msgqueue.c
>> @@ -72,8 +72,6 @@ int wilc_mq_send(WILC_MsgQueueHandle *pHandle,
>>   		goto ERRORHANDLER;
>>   	}
>>   
>> -	spin_lock_irqsave(&pHandle->strCriticalSection, flags);
>> -
>>   	/* construct a new message */
>>   	pstrMessage = kmalloc(sizeof(Message), GFP_ATOMIC);
> As you have moved the lock, can you also change this to GFP_KERNEL as
> well because we do not have a lock held?
>
> And how have you tested that this is ok?  What is this lock trying to
> protect?

This function is called even in interrupt context, so GFP_ATOMIC should be called. The spinlock
also should protect pstrMessage from allocating the memory, so we don't place it to the beginning
of critical section as Chandra said.

Thanks,
Tony.

> thanks,
>
> greg k-h
> --
> To unsubscribe from this list: send the line "unsubscribe linux-wireless" in
> the body of a message to majordomo@...r.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/