Program main function

The main function of the process is to regularly train information about the subordinate devices added to the device. Suddenly found in some cases, the lower-level device information that will occur in some cases has been incorrect. However, this issue occasionally occasionally occasionally Plus your own blind self-confidence has always thought that there is no problem, I have not paying attention to this problem. Today, the stable recovery condition of this problem is found, and the process of resolving this bug in detail.

Process process

After the BUG recovery, use Strace to track the discovery that will always have problems when the Web gets the following device information is incorrect:

That is, the Web caused by the deadlock problem, which has not been able to get the correct device information when getting a lower device.
After final positioning, this problem is found to be due to the previously created a global array crosstree caused by the number of times of failure to obtain subordinate device information. The rough code is as follows:

int g_supportChNum=32;
int g_chNum=64;
char *g_subDevInfoGetFailTime=NULL;
g_subDevInfoGetFailTime = (char *)malloc(sizeof(g_subDevInfoGetFailTime) *g_supportChNum);
.....
int i=0;
for(i=0;i<g_chNum;i++){
	if(0 != com_getSubDevInfo(i))
		 g_subdevinfogetfailtime [i] = 1; // i = 62 get failed
}

Since the previous mistakes assigned to an array of length 32. However, this device is a device that supports 64 channels. There is a channel where the subordinate device gets failed is at 61 channels.
This has an obvious g_subdevinfogetfailtime that only assigns 32-byte space. In the event of acquiring failure, the 62th byte is operational G_SUBDEVINFOGETFAILTIME [61], which leads to the problem of memory and offshore. In turn, thread death Lock.