Because the irq was requested through device managed resources API
(devm_request_threaded_irq()) it was freed after meson_mmc_remove()
completion, thus after mmc_free_host() has reclaimed meson_host memory.
As this irq is IRQF_SHARED, while using CONFIG_DEBUG_SHIRQ, its handler
get called by free_irq(). So meson_mmc_irq() was called after the
meson_host memory reclamation and was using invalid memory.
We ended up with the following scenario:
device_release_driver()
meson_mmc_remove()
mmc_free_host() /* Freeing host memory */
...
devres_release_all()
devm_irq_release()
__free_irq()
meson_mmc_irq() /* Uses freed memory */
To avoid this, the irq is released in meson_mmc_remove() and in
mseon_mmc_probe() error path before mmc_free_host() gets called.