[Xen-devel] [PATCH 2/4] xen: xen-pciback: Replace GFP_ATOMIC with GFP_KERNEL in pcistub_init_device

[Jia-Ju Bai <baijiaju1990@xxxxxxxxx>]

pcistub_init_device() is never called in atomic context.

The call chain ending up at pcistub_init_device() is:
[1] pcistub_init_device() <- pcistub_seize() <- pcistub_probe()
[2] pcistub_init_device() <- pcistub_init_devices_late() <- 
        xen_pcibk_init()
pcistub_probe() is only set as ".probe" in struct pci_driver.
xen_pcibk_init() is is only set as a parameter of module_init().
These functions are not called in atomic context.

Despite never getting called from atomic context,
pcistub_init_device() calls kzalloc() with GFP_ATOMIC,
which does not sleep for allocation.
GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL,
which can sleep and improve the possibility of sucessful allocation.

This is found by a static analysis tool named DCNS written by myself.
And I also manually check it.

Signed-off-by: Jia-Ju Bai <baijiaju1990@xxxxxxxxx>
---
 drivers/xen/xen-pciback/pci_stub.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/xen/xen-pciback/pci_stub.c 
b/drivers/xen/xen-pciback/pci_stub.c
index 9e480fd..bf8c0d3 100644
--- a/drivers/xen/xen-pciback/pci_stub.c
+++ b/drivers/xen/xen-pciback/pci_stub.c
@@ -364,7 +364,7 @@ static int pcistub_init_device(struct pci_dev *dev)
         * here and then to call kfree(pci_get_drvdata(psdev->dev)).
         */
        dev_data = kzalloc(sizeof(*dev_data) +  strlen(DRV_NAME "[]")
-                               + strlen(pci_name(dev)) + 1, GFP_ATOMIC);
+                               + strlen(pci_name(dev)) + 1, GFP_KERNEL);
        if (!dev_data) {
                err = -ENOMEM;
                goto out;
-- 
1.9.1


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel