[PATCH v2 6/6] xen/domain: Added debug safety in the domain_create() failure path

[Andrew Cooper <andrew.cooper3@citrix.com>]

Hitting the fail path with err = 0 causes callers to dereference a NULL
pointer, as 0 fails an IS_ERR() check.

All of the paths appear to be fine, but leave some logic to help catch stray
misuses.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: George Dunlap <George.Dunlap@eu.citrix.com>
CC: Jan Beulich <JBeulich@suse.com>
CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Tim Deegan <tim@xen.org>
CC: Wei Liu <wei.liu2@citrix.com>

v2:
 * Completely different implementation
---
 xen/common/domain.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/xen/common/domain.c b/xen/common/domain.c
index 3cefe76..fd054db 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -399,6 +399,9 @@ struct domain *domain_create(domid_t domid, unsigned int domcr_flags,
     return d;
 
  fail:
+    ASSERT(err < 0);      /* Sanity check paths leading here. */
+    err = err ?: -EINVAL; /* Release build safety. */
+
     d->is_dying = DOMDYING_dead;
     if ( hardware_domain == d )
         hardware_domain = old_hwdom;
-- 
2.1.4


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