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New: Function c4iw_rdev_open() does not set error code when the call to __get_free_page() fails.

Bug 188821 bugzilla-daemon-590EEB7GvNiWaY/[email protected] 1 participant 1 message Nov 25, 2016 InfiniBand

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https://bugzilla.kernel.org/show_bug.cgi?id=188821

Bug ID: 188821
Summary: Function c4iw_rdev_open() does not set error code when
the call to __get_free_page() fails.
Product: Drivers
Version: 2.5
Kernel Version: linux-4.9-rc6
Hardware: All
OS: Linux
Tree: Mainline
Status: NEW
Severity: normal
Priority: P1
Component: Infiniband/RDMA
Assignee: drivers_infiniband-rdma-ztI5WcYan/[email protected]
Reporter: [email protected]
Regression: No

Function __get_free_page() returns a NULL pointer if there is no enough memory. In function c4iw_rdev_open defined in file drivers/infiniband/hw/cxgb4/device.c, __get_free_page() is called and its return value is checked against NULL (at line 831). When the return value is NULL, the control flow jumps to label "destroy_ocqp_pool", and returns the value of variable err. However, after the check of variable err at line 825, the value of err must be 0. As a result, 0 (indicates success) may be returned even when the memory allocation fails. Maybe it is better to assign "-ENOMEM" to err before the jump instruction at line 832. Codes related to this bug are summarised as follows.

c4iw_rdev_open @@ drivers/infiniband/hw/cxgb4/device.c
752 static int c4iw_rdev_open(struct c4iw_rdev *rdev) 753 {

 754     int err;
         ...

824 err = c4iw_ocqp_pool_create(rdev);
825 if (err) {
826 printk(KERN_ERR MOD "error %d initializing ocqp pool\n", err);
827 goto destroy_rqtpool;
828 }
829 rdev->status_page = (struct t4_dev_status_page *)
830 __get_free_page(GFP_KERNEL);
831 if (!rdev->status_page)
832 goto destroy_ocqp_pool; // insert "err = -ENOMEM" before this
line?

         ...

851 return 0;
852 destroy_ocqp_pool:
853 c4iw_ocqp_pool_destroy(rdev);
854 destroy_rqtpool:
855 c4iw_rqtpool_destroy(rdev);
856 destroy_pblpool:
857 c4iw_pblpool_destroy(rdev);
858 destroy_resource:
859 c4iw_destroy_resource(&rdev->resource);
860 return err;
861 }

Thanks very much!

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