On 8/20/20 1:59 PM, Paul Cercueil wrote:

Hi,

Le dim. 16 août 2020 à 12:52, madhuparnabhowmik10@gmail.com a écrit :

quoted

From: Madhuparna Bhowmik <redacted>

In probe IRQ is requested before zchan->id is initialized which can be
read in the irq handler. Hence, shift request irq and enable clock after
other initializations complete. Here, enable clock part is not part of
the race, it is just shifted down after request_irq to keep the error
path same as before.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Madhuparna Bhowmik <redacted>

I don't think there is a race at all, the interrupt handler won't be 
called before the DMA is registered.

 From a purely formal verification perspective there is a bug. The 
interrupt could fire if i.e. the hardware is buggy or something. In 
general it is a good idea to not request the IRQ until all the resources 
that are used in the interrupt handler are properly set up. Even if you 
know that in practice the interrupt will never fire this early.