kernel: ext4: avoid use-after-free in ext4_ext_show_leaf()

In the Linux kernel, the following vulnerability has been resolved: ext4: avoid use-after-free in ext4extshowleaf In ext4findextent, path may be freed by error or be reallocated, so using a previously saved ppath may have been freed and thus may trigger use-after-free, as follows: ext4splitextent...