8250_pci.c, parport_serial.c, __devinit and !CONFIG_HOTPLUG

[Magnus Damm]

Hi all,

I've spotted a case where functions marked as __devinit may be used
after being freed.

8250_pci.c contains find_quirk() which is accessing
pci_serial_quirks[]. The functions pointed to by
pci_serial_quirks[x].init are marked as __devinit.

8250_pci.c exports pciserial_init_ports() which is using find_quirk().
pciserial_init_ports() may be used after __devinit data has been freed
from the module.

If parport_serial gets loaded after 8250_pci and CONFIG_HOTPLUG is
disabled and the quirk table is matching then we might call a
non-existing function.

I may of course be wrong, but it does look like a use-after-free
problem to me. I discovered this by running modpost on a vmlinux that
contains relocation information.

/ magnus
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