PFNs busy flood during vchiq_test

Eric Anholt eric at
Mon Aug 28 09:34:56 PDT 2017

Stefan Wahren <stefan.wahren at> writes:

> Hi Eric,
> after fixing the HIGHMEM issue [1] in vchiq driver, i wanted to test vchiq_test on RPI3 64-bit (4.13rc6).
> The program works, but after some iterations i got a lot of PFN busy messages from the kernel.
> I've seen you already had this problem with vc4. Is there a solution for this?

Other than deleting the message, no.  I've had to tell all the distros
to do so, because mm thinks this spam at runtime is appropriate because
CMA is just badly architected.
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