Bug 2400633 (CVE-2025-39921)

Summary: CVE-2025-39921 kernel: spi: microchip-core-qspi: stop checking viability of op->max_freq in supports_op callback
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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OS: Linux   
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Description OSIDB Bzimport 2025-10-01 09:01:56 UTC
In the Linux kernel, the following vulnerability has been resolved:

spi: microchip-core-qspi: stop checking viability of op->max_freq in supports_op callback

In commit 13529647743d9 ("spi: microchip-core-qspi: Support per spi-mem
operation frequency switches") the logic for checking the viability of
op->max_freq in mchp_coreqspi_setup_clock() was copied into
mchp_coreqspi_supports_op(). Unfortunately, op->max_freq is not valid
when this function is called during probe but is instead zero.
Accordingly, baud_rate_val is calculated to be INT_MAX due to division
by zero, causing probe of the attached memory device to fail.

Seemingly spi-microchip-core-qspi was the only driver that had such a
modification made to its supports_op callback when the per_op_freq
capability was added, so just remove it to restore prior functionality.