mm, slab: clean up slab->obj_exts always

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: mm, slab: clean up slab->obj_exts always When memory allocation profiling is disabled at runtime or due to an error, shutdown_mem_profiling() is called: slab->obj_exts which previously allocated remains. It won't be cleared by unaccount_slab() because of mem_alloc_profiling_enabled() not true. It's incorrect, slab->obj_exts should always be cleaned up in unaccount_slab() to avoid following error: [...]BUG: Bad page state in process... .. [...]page dumped because: page still charged to cgroup [andriy.shevchenko@linux.intel.com: fold need_slab_obj_ext() into its only user]

References

• https://git.kernel.org/stable/c/dab2a13059a475b6392550f882276e170fe2fcff
• https://git.kernel.org/stable/c/01db0e1a48345aa1937f3bdfc7c7108d03ebcf7e
• https://git.kernel.org/stable/c/be8250786ca94952a19ce87f98ad9906448bc9ef