* Kees Cook [off-list ref] wrote:

quoted

git commit b5a882fcf146c87cb6b67c6df353e1c042b8773d
"s390: restore address space when returning to user space".

If I'm understanding this, it won't catch corruption of addr_limit
during fast-path syscalls, though (i.e. addr_limit changed without a
call to set_fs()). :(

Nor does it, or the patch you propose, protect against against something 
corrupting task->mm pointer, or the task->*uid values, or any of the myriads of 
security relevant values stored in the task structure!

Making sure API (set_fs()) usage is bug-free and protecting against the effects of 
general data corruption are two unrelated things that should not mixed.

Thanks,

	Ingo