On Fri, Mar 20, 2020 at 04:21:06PM -0700, Stephen Boyd wrote: > Quoting Vincenzo Frascino (2020-03-20 07:53:43) > > The compat vdso library had some checks that are not anymore relevant. > > Can we get the information on why they aren't relevant anymore in the > commit text? I'd rather not find this commit three years from now and > have no idea why it was applied. Good point. But I'd rather say that the original reason for adding them was bogus (ABI compatibility between arm64 compat and arm32, when arm32 vdso never got them). There may be some (very hard to justify) reason to add them if we want compatibility between vdso and syscall fallback on addresses greater than TASK_SIZE. The vdso code generates a SIGSEGV or SIGBUS while the syscall returns -EFAULT. However, you'd have similar mismatch on unmapped addresses below TASK_SIZE which cannot be handled by the vdso (not a simple comparison). I think the vdsotest code should be adjusted accordingly. -- Catalin
