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| author |   Wen Yang <wen.yang99@zte.com.cn> | 2019-01-15 10:31:27 +0800 |
|---|---|---|
| committer |   Boris Ostrovsky <boris.ostrovsky@oracle.com> | 2019-01-15 16:13:47 -0500 |
| commit | b4711098066f1cf808d4dc11a1a842860a3292fe (patch) | |
| tree | 4c628a969f0ba0333be86b28307815ba91e21d60 /drivers/xen | |
| parent | always clear the X2APIC_ENABLE bit for PV guest (diff) | |
| download | linux-dev-b4711098066f1cf808d4dc11a1a842860a3292fe.tar.xz linux-dev-b4711098066f1cf808d4dc11a1a842860a3292fe.zip | |
pvcalls-front: fix potential null dereference
static checker warning:
drivers/xen/pvcalls-front.c:373 alloc_active_ring()
error: we previously assumed 'map->active.ring' could be null
(see line 357)
drivers/xen/pvcalls-front.c
351 static int alloc_active_ring(struct sock_mapping *map)
352 {
353 void *bytes;
354
355 map->active.ring = (struct pvcalls_data_intf *)
356 get_zeroed_page(GFP_KERNEL);
357 if (!map->active.ring)
^^^^^^^^^^^^^^^^^
Check
358 goto out;
359
360 map->active.ring->ring_order = PVCALLS_RING_ORDER;
361 bytes = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
362 PVCALLS_RING_ORDER);
363 if (!bytes)
364 goto out;
365
366 map->active.data.in = bytes;
367 map->active.data.out = bytes +
368 XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER);
369
370 return 0;
371
372 out:
--> 373 free_active_ring(map);
^^^
Add null check on map->active.ring before dereferencing it to avoid
any NULL pointer dereferences.
Fixes: 9f51c05dc41a ("pvcalls-front: Avoid get_free_pages(GFP_KERNEL) under spinlock")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Suggested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
CC: Boris Ostrovsky <boris.ostrovsky@oracle.com>
CC: Juergen Gross <jgross@suse.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Dan Carpenter <dan.carpenter@oracle.com>
CC: xen-devel@lists.xenproject.org
CC: linux-kernel@vger.kernel.org
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Diffstat (limited to 'drivers/xen')
| -rw-r--r-- | drivers/xen/pvcalls-front.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c index 307861f9e485..8a249c95c193 100644 --- a/drivers/xen/pvcalls-front.c +++ b/drivers/xen/pvcalls-front.c @@ -343,6 +343,9 @@ int pvcalls_front_socket(struct socket *sock) static void free_active_ring(struct sock_mapping *map) { + if (!map->active.ring) + return; + free_pages((unsigned long)map->active.data.in, map->active.ring->ring_order); free_page((unsigned long)map->active.ring); |