In the Linux kernel, the following vulnerability has been resolved: accel: ethosu: Don't read the U65 rounding mode as a storage mode Bits 15:14 of NPU_SET_{IFM,OFM}_PRECISION select the activation storage mode on U85 only

Overview

In the Linux kernel, the following vulnerability has been resolved:

accel: ethosu: Don't read the U65 rounding mode as a storage mode

Bits 15:14 of NPU_SET_{IFM,OFM}_PRECISION select the activation storage mode on U85 only. On U65 the same field holds the rounding mode, and the command stream parser has read it as a storage mode since the driver was added.

That went unnoticed while unknown values fell through the switch, but now that they are rejected, every U65 command stream that asks for natural rounding (2) fails CMDSTREAM_BO_CREATE with -EINVAL. Mesa emits it for average pooling, concatenation, split, unpack, strided slice, LUT and argmax, which is 72 failures of the Teflon test suite on an i.MX93. Truncating rounding (1) is misread as well: it picks the two-tile address path and computes a bogus feature map size from tile bases the command stream never set.

Read the field as a storage mode only on the hardware where it is one.

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.