Jan Beulich
2011-Jul-08 08:41 UTC
[Xen-devel] [PATCH] linux-2.6.18/blkfront: avoid NULL de-reference in CDROM ioctl handling
Just like already done in the default case, for CDROM_GET_CAPABILITY
info->gd should not be blindly de-referenced, as the ioctl can be
called prior to full device setup having completed.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
--- a/drivers/xen/blkfront/blkfront.c
+++ b/drivers/xen/blkfront/blkfront.c
@@ -566,12 +566,11 @@ int blkif_ioctl(struct block_device *bd,
return -EFAULT;
return 0;
- case CDROM_GET_CAPABILITY: {
- struct gendisk *gd = info->gd;
- if (gd->flags & GENHD_FL_CD)
+ case CDROM_GET_CAPABILITY:
+ if (info->gd && (info->gd->flags & GENHD_FL_CD))
return 0;
return -EINVAL;
- }
+
default:
if (info->mi && info->gd) {
switch (info->mi->major) {
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