Re: [PATCH] PCI: xilinx: Fix NULL pointer dereference

[Nam Cao <namcao@linutronix.de>]

On Mon, Aug 11, 2025 at 05:29:37PM -0500, Bjorn Helgaas wrote:
> On Mon, Aug 11, 2025 at 07:41:44AM +0200, Nam Cao wrote:
> > Commit f29861aa301c5 ("PCI: xilinx: Switch to
> > msi_create_parent_irq_domain()") changed xilinx_pcie::msi_domain from child
> > devices' interrupt domain into Xilinx AXI bridge's interrupt domain.
> > 
> > However, xilinx_pcie_intr_handler() wasn't changed and still reads Xilinx
> > AXI bridge's interrupt domain from xilinx_pcie::msi_domain->parent. This
> > pointer is NULL now.
> > 
> > Update xilinx_pcie_intr_handler() to read the correct interrupt domain
> > pointer.
> > 
> > Fixes: f29861aa301c5 ("PCI: xilinx: Switch to msi_create_parent_irq_domain()")
> 
> Since this appeared in v6.17-rc1, I suppose this should be merged for
> v6.17, right?  I provisionally put this on pci/for-linus for now.

Yes please.

> What does this look like to a user?  I assume a NULL pointer
> dereference in xilinx_pcie_intr_handler()?  Do you have a dmesg
> snippet from hitting it?  It would be nice to include a couple lines
> of that in the commit log to help users find this fix.

Sorry I didn't clarify this, but this has not been tested with hardware.

Claudiu pointed out this problem with another driver [1], so I audited all
the other drivers that I touched and noticed that this one has the same
problem.

Nam

https://lore.kernel.org/linux-pci/20250809144447.3939284-1-claudiu.beznea.uj@bp.renesas.com/ [1]