Message ID | 20101208160500.GQ22381@us.ibm.com |
---|---|
State | New |
Headers | show |
On Wed, 8 Dec 2010 10:05:00 -0600 Ryan Harper <ryanh@us.ibm.com> wrote: > If a user decides to punish a guest by revoking its block device via > drive_del, and subsequently also attempts to remove the pci device > backing it, and the device is using blockdev_auto_del() then we get a > segfault when we attempt to access dinfo->auto_del.[1] > > The fix is to check if drive_get_by_blockdev() actually returns a valid > dinfo pointer or not. > > 1. (qemu) pci_add auto storage file=images/test01.raw,if=virtio,id=block1,snapshot=on > (qemu) drive_del block1 > (qemu) pci_del 5 > *segfault* > > Signed-off-by: Ryan Harper <ryanh@us.ibm.com> Fixes my test case: Tested-by: Luiz Capitulino <lcapitulino@redhat.com>
Am 08.12.2010 17:05, schrieb Ryan Harper: > If a user decides to punish a guest by revoking its block device via > drive_del, and subsequently also attempts to remove the pci device > backing it, and the device is using blockdev_auto_del() then we get a > segfault when we attempt to access dinfo->auto_del.[1] > > The fix is to check if drive_get_by_blockdev() actually returns a valid > dinfo pointer or not. > > 1. (qemu) pci_add auto storage file=images/test01.raw,if=virtio,id=block1,snapshot=on > (qemu) drive_del block1 > (qemu) pci_del 5 > *segfault* > > Signed-off-by: Ryan Harper <ryanh@us.ibm.com> Thanks, applied to the block branch. Kevin
diff --git a/blockdev.c b/blockdev.c index f6ac439..3b3b82d 100644 --- a/blockdev.c +++ b/blockdev.c @@ -30,14 +30,16 @@ void blockdev_mark_auto_del(BlockDriverState *bs) { DriveInfo *dinfo = drive_get_by_blockdev(bs); - dinfo->auto_del = 1; + if (dinfo) { + dinfo->auto_del = 1; + } } void blockdev_auto_del(BlockDriverState *bs) { DriveInfo *dinfo = drive_get_by_blockdev(bs); - if (dinfo->auto_del) { + if (dinfo && dinfo->auto_del) { drive_uninit(dinfo); } }
If a user decides to punish a guest by revoking its block device via drive_del, and subsequently also attempts to remove the pci device backing it, and the device is using blockdev_auto_del() then we get a segfault when we attempt to access dinfo->auto_del.[1] The fix is to check if drive_get_by_blockdev() actually returns a valid dinfo pointer or not. 1. (qemu) pci_add auto storage file=images/test01.raw,if=virtio,id=block1,snapshot=on (qemu) drive_del block1 (qemu) pci_del 5 *segfault* Signed-off-by: Ryan Harper <ryanh@us.ibm.com>