net: hibmcge: fix the division by zero issue

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: net: hibmcge: fix the division by zero issue When the network port is down, the queue is released, and ring->len is 0. In debugfs, hbg_get_queue_used_num() will be called, which may lead to a division by zero issue. This patch adds a check, if ring->len is 0, hbg_get_queue_used_num() directly returns 0.

References

• https://git.kernel.org/stable/c/c945e1ad4f3b77166a3215dabc0c6c980d4a9c73
• https://git.kernel.org/stable/c/475e06113c615dafd44262d6d6bd37786f7f4206
• https://git.kernel.org/stable/c/7004b26f0b64331143eb0b312e77a357a11427ce