> On Mar 14, 2019, at 10:27 AM, Robert Elz <k...@munnari.oz.au> wrote:
>
> Date: Thu, 14 Mar 2019 08:06:58 -0700
> From: Jason Thorpe <thor...@me.com>
> Message-ID: <134778ad-a675-414a-bbb3-7eeeaf2c2...@me.com>
>
> | Great sleuthing, you pretty much nailed it.
>
> OK, great. This is the patch I plan to commit soon (rather than
> waiting on lots of review - so that the b5 tests can start working
> again ASAP).
>
> If anyone has any issues with this, please make them known soon
> (as in quite soon...)
Looks good to me. This is probably worth pulling up to netbsd-8 as well.
> Also, after this patch, I tested address wraparround (addr+llen < addr)
> and get the ENOMEM error that the patch returns (which seems to be the
> error that POSIX specifies for this kind of thing. Ans speaking of which
> we appear to differ with POSIX in several error codes, POSIX does not use
> EINVAL for mlock/munlock of a region which crosses a "hole" that would be
> ENOMEM (munlock converts the internal EINVAL into ENOMEM before returning,
> mlock() doesn't), and munlock() without a preceding mlock is not an error
> at all (POSIX says "regardless of how many times mlock( ) has been called by
> the process for any of the pages in the specified range." Zero is a
> number of times that mlock() might have been called. ALso, EAGAIN is
> correct for mlock() when the max number of pages the kernel will allow
> to be locked have been locked, but not for the case when a process exceeds
> its resource limit of locked pages ... that should be ENOMEM. There
> might be more like this. This patch doesn't do anything with those
> issues, they're not urgent, and we can fix them anytime (if we agree to
> do so.)
Yes, we should fix the error return cases as well.
>
> kre
>
> Index: uvm_map.c
> ===================================================================
> RCS file: /cvsroot/src/sys/uvm/uvm_map.c,v
> retrieving revision 1.358
> diff -u -r1.358 uvm_map.c
> --- uvm_map.c 3 Mar 2019 17:37:36 -0000 1.358
> +++ uvm_map.c 14 Mar 2019 16:29:57 -0000
> @@ -3359,6 +3359,14 @@
> }
> entry = start_entry;
>
> + if (start == end) { /* nothing required */
> + if ((lockflags & UVM_LK_EXIT) == 0)
> + vm_map_unlock(map);
> +
> + UVMHIST_LOG(maphist,"<- done (nothing)",0,0,0,0);
> + return 0;
> + }
> +
> /*
> * handle wiring and unwiring separately.
> */
> Index: uvm_mmap.c
> ===================================================================
> RCS file: /cvsroot/src/sys/uvm/uvm_mmap.c,v
> retrieving revision 1.169
> diff -u -r1.169 uvm_mmap.c
> --- uvm_mmap.c 19 Dec 2017 18:34:47 -0000 1.169
> +++ uvm_mmap.c 14 Mar 2019 16:29:58 -0000
> @@ -759,8 +759,12 @@
>
> pageoff = (addr & PAGE_MASK);
> addr -= pageoff;
> - size += pageoff;
> - size = (vsize_t)round_page(size);
> + if (size != 0) {
> + size += pageoff;
> + size = (vsize_t)round_page(size);
> + }
> + if (addr + size < addr)
> + return ENOMEM;
>
> error = range_test(&p->p_vmspace->vm_map, addr, size, false);
> if (error)
> @@ -810,8 +814,12 @@
>
> pageoff = (addr & PAGE_MASK);
> addr -= pageoff;
> - size += pageoff;
> - size = (vsize_t)round_page(size);
> + if (size != 0) {
> + size += pageoff;
> + size = (vsize_t)round_page(size);
> + }
> + if (addr + size < addr)
> + return ENOMEM;
>
> error = range_test(&p->p_vmspace->vm_map, addr, size, false);
> if (error)
> Index: uvm_page.c
> ===================================================================
> RCS file: /cvsroot/src/sys/uvm/uvm_page.c,v
> retrieving revision 1.198
> diff -u -r1.198 uvm_page.c
> --- uvm_page.c 19 May 2018 15:03:26 -0000 1.198
> +++ uvm_page.c 14 Mar 2019 16:29:58 -0000
> @@ -1605,9 +1605,11 @@
> uvm_pageunwire(struct vm_page *pg)
> {
> KASSERT(mutex_owned(&uvm_pageqlock));
> + KASSERT(pg->wire_count != 0);
> pg->wire_count--;
> if (pg->wire_count == 0) {
> uvm_pageactivate(pg);
> + KASSERT(uvmexp.wired != 0);
> uvmexp.wired--;
> }
> }
>
>
-- thorpej
