Re: [PATCH] i2c:at91: Fix a race condition during signal handling in at91_do_twi_xfer.

[Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>]

[-- Attachment #1: Type: text/plain, Size: 1044 bytes --]

On Tue, Aug 26, 2014 at 09:13:24PM +0200, Simon Lindgren wrote:
> There is a race condition in at91_do_twi_xfer when signals arrive.
> If a signal is recieved while waiting for a transfer to complete
> wait_for_completion_interruptible_timeout() will return -ERESTARTSYS.
> This is not handled correctly resulting in interrupts still being
> enabled and a transfer being in flight when we return.
> 
> Symptoms include a range of oopses and bus lockups. Oopses can happen
> when the transfer completes because the interrupt handler will corrupt
> the stack. If a new transfer is started before the interrupt fires
> the controller will start a new transfer in the middle of the old one,
> resulting in confused slaves and a locked bus.
> 
> To avoid this, use wait_for_completion_io_timeout instead so that we
> don't have to deal with gracefully shutting down the transfer and
> disabling the interrupts.
> 
> Signed-off-by: Simon Lindgren <simon-IfRblWqrl23QT0dZR+AlfA@public.gmane.org>

Applied to for-current, thanks!


[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 819 bytes --]