Re: [PATCH v2] PCI: vmd: Fix wrong kfree() in vmd_msi_free()

[Thomas Gleixner <tglx@linutronix.de>]

On Thu, Aug 07 2025 at 10:10, Nam Cao wrote:
> vmd_msi_alloc() allocates struct vmd_irq and stashes it into
> irq_data->chip_data associated with the VMD's interrupt domain.
> vmd_msi_free() extracts the pointer by calling irq_get_chip_data() and
> frees it.
>
> irq_get_chip_data() returns the chip_data associated with the top interrupt
> domain. This worked in the past, because VMD's interrupt domain was the top
> domain.
>
> But since commit d7d8ab87e3e7 ("PCI: vmd: Switch to
> msi_create_parent_irq_domain()") changed the interrupt domain hierarchy,
> VMD's interrupt domain is not the top domain anymore. irq_get_chip_data()
> now returns the chip_data at the MSI devices' interrupt domains. It is
> therefore broken for vmd_msi_free() to kfree() this chip_data.
>
> Fix this issue, correctly extract the chip_data associated with the VMD's
> interrupt domain.
>
> Fixes: d7d8ab87e3e7 ("PCI: vmd: Switch to msi_create_parent_irq_domain()")
> Reported-by: Kenneth Crudup <kenny@panix.com>
> Closes: https://lore.kernel.org/linux-pci/dfa40e48-8840-4e61-9fda-25cdb3ad81c1@panix.com/
> Reported-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
> Closes: https://lore.kernel.org/linux-pci/ed53280ed15d1140700b96cca2734bf327ee92539e5eb68e80f5bbbf0f01@linux.gnuweeb.org/
> Tested-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
> Tested-by: Kenneth Crudup <kenny@panix.com>
> Signed-off-by: Nam Cao <namcao@linutronix.de>

Reviewed-by: Thomas Gleixner <tglx@linutronix.de>