linux-kernel - Re: kernel panic with simple driver

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

Date:	Wed, 10 Aug 2011 11:29:09 +0900
From:	"Murali K. Vemuri" <vemuri.muralikrishna@...il.com>
To:	Greg KH <greg@...ah.com>
Cc:	Ryan Mallon <rmallon@...il.com>, linux-kernel@...r.kernel.org
Subject: Re: kernel panic with simple driver

On Wed, Aug 10, 2011 at 11:16 AM, Greg KH <greg@...ah.com> wrote:
> On Wed, Aug 10, 2011 at 10:33:28AM +0900, Murali K. Vemuri wrote:
>> There is no concurrent access to the timer. The design is that:
>> 1.Driver provides an IOCTL for start / stop
>> 2. when the driver receives START IOCTL, it toggles some GPIOs to ON / OFF.
>> 3. the GPIOs will be ON for 500 MSec and OFF for 500 MSec.
>> 4. Two successive START IOCTLs will not be honored.
>> 5. There is only one application that uses these IOCTLs
>> 6. When I receive a STOP IOCTL, I am doing :
>> if (timer_pending (&my_timer))
>> del_timer(&my_timer);
>
> What kind of driver is this?  For what type of hardware?
>
> Can't you control the gpios from userspace with out any need to write a
> kernel driver?
>

This driver is meant for controlling some LEDs. The CPU is OMAP 3530
and the OS is Android.
>From the user space, I could not control the GPIOs directly, and thus
I ended up supporting in the form of a simple driver.
I agree that these are better done from the user space, but as much as
I google'd studied, I could not find any better way to implement this.

If anyone has more info, that is also highly appreciated.
Thanks
Murali

> thanks,
>
> greg k-h
>
--
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/