Re: [PATCH] irqdomain/treewide: Keep firmware node unconditionally allocated

[Bjorn Helgaas]

On Thu, Jul 09, 2020 at 11:53:06AM +0200, Thomas Gleixner wrote:
> Quite some non OF/ACPI users of irqdomains allocate firmware nodes of type
> IRQCHIP_FWNODE_NAMED or IRQCHIP_FWNODE_NAMED_ID and free them right after
> creating the irqdomain. The only purpose of these FW nodes is to convey
> name information. When this was introduced the core code did not store the
> pointer to the node in the irqdomain. A recent change stored the firmware
> node pointer in irqdomain for other reasons and missed to notice that the
> usage sites which do the alloc_fwnode/create_domain/free_fwnode sequence
> are broken by this. Storing a dangling pointer is dangerous itself, but in
> case that the domain is destroyed later on this leads to a double free.
> 
> Remove the freeing of the firmware node after creating the irqdomain from
> all affected call sites to cure this.
> 
> Fixes: 711419e504eb ("irqdomain: Add the missing assignment of domain->fwnode for named fwnode")
> Reported-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx

Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>	# drivers/pci/