Re: [PATCH] PCI: sysfs: Reject unaligned resource I/O port accesses

[Bjorn Helgaas]

On Fri, Aug 21, 2026 at 07:16:32AM +0530, Deepanshu Kartikey wrote:
> On Sun, Aug 9, 2026 at 10:29 AM Deepanshu Kartikey
> <kartikey406@xxxxxxxxx> wrote:
> >
> > pci_resource_io() validates that off+count stays within the BAR's
> > range but never checks that the resulting port is aligned to the
> > access size. A pwrite64()/pread64() on a resourceN file with an odd
> > offset and count=2 or count=4 reaches outw()/outl() with a misaligned
> > address. On arm64 this becomes a store/load to a Device-memory
> > mapping (PCI_IOBASE + port), which architecturally requires natural
> > alignment, causing an alignment fault and kernel oops.
> >
> > Reject misaligned accesses before they reach the low-level accessor.
> >
> > Reported-by: syzbot+7134530b25073b4ef373@xxxxxxxxxxxxxxxxxxxxxxxxx
> > Closes: https://syzkaller.appspot.com/bug?extid=7134530b25073b4ef373
> > Signed-off-by: Deepanshu Kartikey <kartikey406@xxxxxxxxx>
> > ---
> >  drivers/pci/pci-sysfs.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> > index 5ec0b245a69b..72f0404a34e9 100644
> > --- a/drivers/pci/pci-sysfs.c
> > +++ b/drivers/pci/pci-sysfs.c
> > @@ -1175,6 +1175,9 @@ static ssize_t pci_resource_io(struct file *filp, struct kobject *kobj,
> >         if (port + count - 1 > pci_resource_end(pdev, bar))
> >                 return -EINVAL;
> >
> > +       if (!IS_ALIGNED(port, count))
> > +               return -EINVAL;
> > +
> >         switch (count) {
> >         case 1:
> >                 if (write)
> > --
> > 2.43.0
> >
> 
> Gentle Reminder. Please let me know the status of this patch

We're in the middle of the merge window, so won't be adding new
material until after v7.3-rc1 (probably Aug 31).