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Description of problem:

Covscan reports a possible NULL dereference in qcow2_check_refcounts.c:
    qemu-kvm-0.12.1.2/block/qcow2-refcount.c:1390: returned_null: Function "g_realloc(gpointer, gsize)" returns null.
    qemu-kvm-0.12.1.2/block/qcow2-refcount.c:1390: var_assigned: Assigning: "refcount_table" = null return value from "g_realloc(gpointer, gsize)".
    qemu-kvm-0.12.1.2/block/qcow2-refcount.c:1395: dereference: Dereferencing a null pointer "refcount_table".


Here is the patch that introduced the problem:

    commit 2f2ce9aa507d233f9a3c690e2cf815e7162de56c
    Author: Max Reitz <mreitz>
    Date:   Fri May 2 16:58:43 2014 -0500

        qcow2-refcount: Repair shared refcount blocks
    

Version-Release number of selected component (if applicable):
qemu-kvm-0.12.1.2-2.427.el6

How reproducible:
N/A

g_realloc() may only return NULL if the number of bytes requested is zero. nb_clusters is guaranteed to be non-zero, therefore g_realloc() should never return NULL here.

I'll add an assertion for refcount_table to be non-NULL, which will hopefully silence covscan.

*** Bug 1102416 has been marked as a duplicate of this bug. ***

Fix included in qemu-kvm-0.12.1.2-2.441.el6

This is incorrect result for coverity scan. Custom model file was added to our coverity packages to handle this situation properly.