Re: locking question: do_mmap(), do_munmap()

Alexander Viro
1999-10-10T16:07:38Z

[Cc'd to mingo]

On Sun, 10 Oct 1999, Manfred Spraul wrote:

> I've started adding "assert_down()" and "assert_kernellocked()" macros,
> and now I don't see the login prompt any more...
>
> eg. sys_mprotect calls merge_segments without lock_kernel().

Manfred, Andrea - please stop it. Yes, it does and yes, it should.
Plonking the big lock around every access to VM is _not_ a solution. If
swapper doesn't use mmap_sem - _swapper_ should be fixed. How the hell
does lock_kernel() have smaller deadlock potential than
down(&mm->mmap_sem)?

If you want to return to 2.2 you know where to find it.