pcmcia: Fix a NULL pointer dereference in __iodyn_find_io_region()

In __iodyn_find_io_region(), pcmcia_make_resource() is assigned to
res and used in pci_bus_alloc_resource(). There is a dereference of res
in pci_bus_alloc_resource(), which could lead to a NULL pointer
dereference on failure of pcmcia_make_resource().

Fix this bug by adding a check of res.

Cc: stable@vger.kernel.org
Fixes: 49b1153adfe1 ("pcmcia: move all pcmcia_resource_ops providers into one module")
Signed-off-by: Ma Ke <make24@iscas.ac.cn>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

diff --git a/drivers/pcmcia/rsrc_iodyn.c b/drivers/pcmcia/rsrc_iodyn.c
index b04b16496b0c4b76ebb381b5965f69dfc817f950..2677b577c1f85862df5400483d09e55c51422a2b 100644 (file)
--- a/drivers/pcmcia/rsrc_iodyn.c
+++ b/drivers/pcmcia/rsrc_iodyn.c
@@ -62,6 +62,9 @@ static struct resource *__iodyn_find_io_region(struct pcmcia_socket *s,
        unsigned long min = base;
        int ret;
 
+       if (!res)
+               return NULL;
+
        data.mask = align - 1;
        data.offset = base & data.mask;