blkback: don't call vbd_size() if bd_disk is NULL

PATCH In review Laszlo Ersek 3 participants 3 messages May 25, 2011 Xen hypervisor interface

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Laszlo Ersek

author

2011-05-25 10:24 UTC #0 lore raw

PATCH 1/1 blkback: don't call vbd_size() if bd_disk is NULL

...because vbd_size() dereferences bd_disk if bd_part is NULL.

Signed-off-by Laszlo Ersek<[email protected]>

---
 drivers/xen/blkback/vbd.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

drivers/xen/blkback/vbd.c +2 -1

diff -r 415a9b435fef drivers/xen/blkback/vbd.c
@@ -73,7 +73,6 @@ int vbd_create(blkif_t *blkif, blkif_vde
 	}
 
 	vbd->bdev = bdev;
-	vbd->size = vbd_size(vbd);
 
 	if (vbd->bdev->bd_disk == NULL) {
 		DPRINTK("vbd_creat: device %08x doesn't exist.\n",

@@ -82,6 +81,8 @@ int vbd_create(blkif_t *blkif, blkif_vde
 		return -ENOENT;
 	}
 
+	vbd->size = vbd_size(vbd);
+
 	if (vbd->bdev->bd_disk->flags & GENHD_FL_CD || cdrom)
 		vbd->type |= VDISK_CDROM;
 	if (vbd->bdev->bd_disk->flags & GENHD_FL_REMOVABLE)

Jan Beulich

Acked-by on v1 1/1

2011-05-25 10:36 UTC #1 lore raw

Quoted 4 lines

Quoted 1 line
Quoted 1 line · Laszlo Ersek
...because vbd_size() dereferences bd_disk if bd_part is NULL.
Signed-off-by Laszlo Ersek<[email protected]>

Acked-by Jan Beulich <[email protected]>

Quoted 29 lines

---
  drivers/xen/blkback/vbd.c |    3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)

diff -r 415a9b435fef drivers/xen/blkback/vbd.c

drivers/xen/blkback/vbd.c +2 -1

@@ -73,7 +73,6 @@ int vbd_create(blkif_t *blkif, blkif_vde
  	}
 
  	vbd->bdev = bdev;
-	vbd->size = vbd_size(vbd);
 
  	if (vbd->bdev->bd_disk == NULL) {
  		DPRINTK("vbd_creat: device %08x doesn't exist.\n",

@@ -82,6 +81,8 @@ int vbd_create(blkif_t *blkif, blkif_vde
  		return -ENOENT;
  	}
 
+	vbd->size = vbd_size(vbd);
+
  	if (vbd->bdev->bd_disk->flags & GENHD_FL_CD || cdrom)
  		vbd->type |= VDISK_CDROM;
  	if (vbd->bdev->bd_disk->flags & GENHD_FL_REMOVABLE)

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Konrad Rzeszutek Wilk

2011-05-25 13:01 UTC #2 lore raw

Quoted 2 lines · Jan Beulich

Quoted 2 lines
Quoted 1 line
Quoted 1 line · Laszlo Ersek
...because vbd_size() dereferences bd_disk if bd_part is NULL.

Which would imply that doing this on disk without any partitions would crash.

Weird, I don't seem to get that problem on a disk without any partitions (just a raw disk). Or does the kernel actually set the bd_part to something even if it does not have any partitions?

Quoted 42 lines

Quoted 2 lines
Signed-off-by Laszlo Ersek<[email protected]>
Acked-by Jan Beulich <[email protected]>
Quoted 25 lines
---
  drivers/xen/blkback/vbd.c |    3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)
diff -r 415a9b435fef drivers/xen/blkback/vbd.c
drivers/xen/blkback/vbd.c +2 -1
@@ -73,7 +73,6 @@ int vbd_create(blkif_t *blkif, blkif_vde
  	}
 
  	vbd->bdev = bdev;
-	vbd->size = vbd_size(vbd);
 
  	if (vbd->bdev->bd_disk == NULL) {
  		DPRINTK("vbd_creat: device %08x doesn't exist.\n",
@@ -82,6 +81,8 @@ int vbd_create(blkif_t *blkif, blkif_vde
  		return -ENOENT;
  	}
 
+	vbd->size = vbd_size(vbd);
+
  	if (vbd->bdev->bd_disk->flags & GENHD_FL_CD || cdrom)
  		vbd->type |= VDISK_CDROM;
  	if (vbd->bdev->bd_disk->flags & GENHD_FL_REMOVABLE)
Quoted 4 lines
_______________________________________________
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[email protected]
http://lists.xensource.com/xen-devel
_______________________________________________
Xen-devel mailing list
[email protected]
http://lists.xensource.com/xen-devel