In the Linux kernel, the following vulnerability has been resolved: mmc: mxcmmc: cancel data work and watchdog on remove mxcmci_remove() frees the host through the devm tail, but neither it nor mmc_remove_host() drains the driver's own…

Overview

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

mmc: mxcmmc: cancel data work and watchdog on remove

mxcmci_remove() frees the host through the devm tail, but neither it nor mmc_remove_host() drains the driver's own asynchronous state. host->watchdog, a 10 s timer armed on the DMA path in mxcmci_setup_data(), is deleted only by the DMA- and IRQ-complete paths, which the remove path does not explicitly drain; it can therefore fire after the host is freed and dereference it in mxcmci_watchdog(). host->datawork, armed from the IRQ handler on the PIO path, is not cancelled by the remove path either.

Free the devm-registered IRQ, then cancel datawork and delete the watchdog in mxcmci_remove(), before dma_release_channel(). Freeing the IRQ first keeps a trailing handler from re-arming datawork between the cancel and the host free. Both callbacks are non-self-rearming.

This issue was found by an in-house static analysis tool.

Remediation

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