There's this problem on the recent gcc-6.1: In file included from conf/domain_conf.c:37:0: conf/domain_conf.c: In function 'virDomainChrPreAlloc': conf/domain_conf.c:14109:35: error: potential null pointer dereference [-Werror=null-dereference] return VIR_REALLOC_N(*arrPtr, *cntPtr + 1); ^~ ./util/viralloc.h:158:73: note: in definition of macro 'VIR_REALLOC_N' # define VIR_REALLOC_N(ptr, count) virReallocN(&(ptr), sizeof(*(ptr)), (count), \ ^~~~~ conf/domain_conf.c: In function 'virDomainChrRemove': conf/domain_conf.c:14133:21: error: potential null pointer dereference [-Werror=null-dereference] for (i = 0; i < *cntPtr; i++) { ^~~~~~~ GCC basically fails to see, that the virDomainChrGetDomainPtrsInternal will never actually return NULL because it's never called over a domain char device with _LAST type. But to make it shut up, lets turn this function into returning an integer and check in the callers if a zero value value was returned. Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- diff to v2: - Yet another improvement as suggested in review of v2 src/conf/domain_conf.c | 39 +++++++++++++++++++++++---------------- 1 file changed, 23 insertions(+), 16 deletions(-) diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index 7d46d0b..9f9fdf2 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -14038,7 +14038,7 @@ virDomainChrFind(virDomainDefPtr def, /* Return the address within vmdef to be modified when working with a * chrdefptr of the given type. */ -static void +static int ATTRIBUTE_RETURN_CHECK virDomainChrGetDomainPtrsInternal(virDomainDefPtr vmdef, virDomainChrDeviceType type, virDomainChrDefPtr ***arrPtr, @@ -14048,28 +14048,30 @@ virDomainChrGetDomainPtrsInternal(virDomainDefPtr vmdef, case VIR_DOMAIN_CHR_DEVICE_TYPE_PARALLEL: *arrPtr = &vmdef->parallels; *cntPtr = &vmdef->nparallels; - break; + return 0; case VIR_DOMAIN_CHR_DEVICE_TYPE_SERIAL: *arrPtr = &vmdef->serials; *cntPtr = &vmdef->nserials; - break; + return 0; case VIR_DOMAIN_CHR_DEVICE_TYPE_CONSOLE: *arrPtr = &vmdef->consoles; *cntPtr = &vmdef->nconsoles; - break; + return 0; case VIR_DOMAIN_CHR_DEVICE_TYPE_CHANNEL: *arrPtr = &vmdef->channels; *cntPtr = &vmdef->nchannels; - break; + return 0; case VIR_DOMAIN_CHR_DEVICE_TYPE_LAST: - *arrPtr = NULL; - *cntPtr = NULL; break; } + + virReportError(VIR_ERR_INTERNAL_ERROR, + _("Unknown char device type: %d"), type); + return -1; } @@ -14085,14 +14087,13 @@ virDomainChrGetDomainPtrs(const virDomainDef *vmdef, size_t *cntVar = NULL; /* Cast away const; we add it back in the final assignment. */ - virDomainChrGetDomainPtrsInternal((virDomainDefPtr) vmdef, type, - &arrVar, &cntVar); - if (arrVar) { + if (virDomainChrGetDomainPtrsInternal((virDomainDefPtr) vmdef, type, + &arrVar, &cntVar) < 0) { + *arrPtr = NULL; + *cntPtr = 0; + } else { *arrPtr = (const virDomainChrDef **) *arrVar; *cntPtr = *cntVar; - } else { - *arrPtr = NULL; - *cntPtr = 0; } } @@ -14104,7 +14105,9 @@ virDomainChrPreAlloc(virDomainDefPtr vmdef, virDomainChrDefPtr **arrPtr = NULL; size_t *cntPtr = NULL; - virDomainChrGetDomainPtrsInternal(vmdef, chr->deviceType, &arrPtr, &cntPtr); + if (virDomainChrGetDomainPtrsInternal(vmdef, chr->deviceType, + &arrPtr, &cntPtr) < 0) + return -1; return VIR_REALLOC_N(*arrPtr, *cntPtr + 1); } @@ -14116,7 +14119,9 @@ virDomainChrInsertPreAlloced(virDomainDefPtr vmdef, virDomainChrDefPtr **arrPtr = NULL; size_t *cntPtr = NULL; - virDomainChrGetDomainPtrsInternal(vmdef, chr->deviceType, &arrPtr, &cntPtr); + if (virDomainChrGetDomainPtrsInternal(vmdef, chr->deviceType, + &arrPtr, &cntPtr) < 0) + return; VIR_APPEND_ELEMENT_INPLACE(*arrPtr, *cntPtr, chr); } @@ -14128,7 +14133,9 @@ virDomainChrRemove(virDomainDefPtr vmdef, virDomainChrDefPtr ret = NULL, **arrPtr = NULL; size_t i, *cntPtr = NULL; - virDomainChrGetDomainPtrsInternal(vmdef, chr->deviceType, &arrPtr, &cntPtr); + if (virDomainChrGetDomainPtrsInternal(vmdef, chr->deviceType, + &arrPtr, &cntPtr) < 0) + return NULL; for (i = 0; i < *cntPtr; i++) { ret = (*arrPtr)[i]; -- 2.8.3