commit e006043a4d2da52bba9fd9cb7e5a22e2951ff69b
author Jack Steiner <steiner@sgi.com> Tue Dec 15 16:48:10 2009 -0800
committer Linus Torvalds <torvalds@linux-foundation.org> Wed Dec 16 07:20:15 2009 -0800
tree 21fcb2c1997b3070b54df12ec4102d2489deeecd
parent 33f3648342dc40f8bd6383a5a1a91c22e06f6b77

gru: check for valid vma

Fix bug caused by failure to allocate a GRU gts structure.  The old code
failed to handle the case where the vma was invalid.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/misc/sgi-gru/grufault.c

diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufault.c
index ada7df7..7466234 100644
--- a/drivers/misc/sgi-gru/grufault.c
+++ b/drivers/misc/sgi-gru/grufault.c
@@ -90,19 +90,22 @@
 {
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
-	struct gru_thread_state *gts = NULL;
+	struct gru_thread_state *gts = ERR_PTR(-EINVAL);
 
 	down_write(&mm->mmap_sem);
 	vma = gru_find_vma(vaddr);
-	if (vma)
-		gts = gru_alloc_thread_state(vma, TSID(vaddr, vma));
-	if (!IS_ERR(gts)) {
-		mutex_lock(&gts->ts_ctxlock);
-		downgrade_write(&mm->mmap_sem);
-	} else {
-		up_write(&mm->mmap_sem);
-	}
+	if (!vma)
+		goto err;
 
+	gts = gru_alloc_thread_state(vma, TSID(vaddr, vma));
+	if (IS_ERR(gts))
+		goto err;
+	mutex_lock(&gts->ts_ctxlock);
+	downgrade_write(&mm->mmap_sem);
+	return gts;
+
+err:
+	up_write(&mm->mmap_sem);
 	return gts;
 }