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.