Description

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

spi: cadence-qspi: remove system-wide suspend helper calls from runtime PM hooks

The ->runtime_suspend() and ->runtime_resume() callbacks are not
expected to call spi_controller_suspend() and spi_controller_resume().
Remove calls to those in the cadence-qspi driver.

Those helpers have two roles currently:
- They stop/start the queue, including dealing with the kworker.
- They toggle the SPI controller SPI_CONTROLLER_SUSPENDED flag. It
requires acquiring ctlr->bus_lock_mutex.

Step one is irrelevant because cadence-qspi is not queued. Step two
however has two implications:
- A deadlock occurs, because ->runtime_resume() is called in a context
where the lock is already taken (in the ->exec_op() callback, where
the usage count is incremented).
- It would disallow all operations once the device is auto-suspended.

Here is a brief call tree highlighting the mutex deadlock:

spi_mem_exec_op()
...
spi_mem_access_start()
mutex_lock(&ctlr->bus_lock_mutex)

cqspi_exec_mem_op()
pm_runtime_resume_and_get()
cqspi_resume()
spi_controller_resume()
mutex_lock(&ctlr->bus_lock_mutex)
...

spi_mem_access_end()
mutex_unlock(&ctlr->bus_lock_mutex)
...

Classification

CVE ID: CVE-2024-26806

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 11.48% (scored less or equal to compared to others)

EPSS Date: 2025-02-04 (when was this score calculated)

References

https://git.kernel.org/stable/c/041562ebc4759c9932b59a06527f8753b86da365
https://git.kernel.org/stable/c/959043afe53ae80633e810416cee6076da6e91c6

Timeline