This matters only if/when this realloc call fails. And then, only in the small way that with this patch, there's a slightly better chance of recovering from the low-memory condition. 2007-06-22 Jim Meyering <jim(a)meyering.net&gt; * qemud/driver.c (qemudMonitorCommand): Avoid leak upon failed realloc. Index: qemud/driver.c =================================================================== RCS file: /data/cvs/libvirt/qemud/driver.c,v retrieving revision 1.21 diff -u -p -r1.21 driver.c --- qemud/driver.c 15 Jun 2007 13:44:19 -0000 1.21 +++ qemud/driver.c 22 Jun 2007 09:43:59 -0000 @@ -75,6 +75,7 @@ int qemudMonitorCommand(struct qemud_ser for (;;) { char data[1024]; int got = read(vm->monitor, data, sizeof(data)); + char *b; if (got == 0) { if (buf) @@ -91,8 +92,11 @@ int qemudMonitorCommand(struct qemud_ser free(buf); return -1; } - if (!(buf = realloc(buf, size+got+1))) + if (!(b = realloc(buf, size+got+1))) { + free(buf); return -1; + } + buf = b; memmove(buf+size, data, got); buf[size+got] = '\0'; size += got;