io_uring/recvmsg using io_provide_buffers causes kernel NULL pointer dereference bug

[Mauro De Gennaro <mauro@xxxxxxxxxxxx>]

Hi,

First time reporting what seems to be a kernel bug, so I apologise if
I am not supposed to send bug reports to this mailing list as well.
The report was filed at Bugzilla:

https://bugzilla.kernel.org/show_bug.cgi?id=213639

It happens on 5.11 and I haven't tested the code yet on newer kernels.

Thank you.

Best,
Mauro