【中文导读】Linux kernel 存在内存破坏、越界访问风险（高危风险）。具体受影响版本、触发条件和修复方案以 NVD/厂商公告为准。 【原始描述】In the Linux kernel, the following vulnerability has been resolved: fs: jfs: fix shift-out-of-bounds in dbAllocAG Syzbot found a crash : UBSAN: shift-out-of-bounds in dbAllocAG. The underlying bug is the missing check of bmp->db_agl2size. The field can be greater than 64 and trigger the shift-out-of-bounds. Fix this bug by adding a check of bmp->db_agl2size in dbMount since this field is used in many following functions. The upper bound for this field is L2MAXL2SIZE - L2MAXAG, thanks for the help of Dave Kleikamp. Note that, for maintenance, I reorganized error handling code of dbMount.