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Pull up following revision(s) (requested by riastradh in ticket #1622): 

sys/uvm/uvm_map.c: revision 1.395

uvm(9): Fix 19-year-old bug in assertion about mmap hint.

Previously this would _first_ remember the original hint, and _then_
clamp the hint to the VM map's range:

        orig_hint = hint;
        if (hint < vm_map_min(map)) {   /* check ranges ... */
                if (flags & UVM_FLAG_FIXED) {
                        UVMHIST_LOG(maphist,"<- VA below map range",0,0,0,0);
                        return (NULL);
                }
                hint = vm_map_min(map);
        ...
        KASSERTMSG(!topdown || hint <= orig_hint, "hint: %#jx, orig_hint: %#jx",
            (uintmax_t)hint, (uintmax_t)orig_hint);

Even if nothing else happens in the ellipsis, taking the branch
guarantees the assertion will fail in the topdown case.
This commit is contained in:
martin 2023-04-01 16:00:28 +00:00
parent ad029167bd
commit e7f7424d79
1 changed files with 13 additions and 7 deletions
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20
sys/uvm/uvm_map.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: uvm_map.c,v 1.362.2.2 2019/11/01 18:24:31 martin Exp $ */
/* $NetBSD: uvm_map.c,v 1.362.2.3 2023/04/01 16:00:28 martin Exp $ */
/*
* Copyright (c) 1997 Charles D. Cranor and Washington University.
@ -66,7 +66,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: uvm_map.c,v 1.362.2.2 2019/11/01 18:24:31 martin Exp $");
__KERNEL_RCSID(0, "$NetBSD: uvm_map.c,v 1.362.2.3 2023/04/01 16:00:28 martin Exp $");
#include "opt_ddb.h"
#include "opt_pax.h"
@ -1882,12 +1882,17 @@ uvm_map_findspace(struct vm_map *map, vaddr_t hint, vsize_t length,
uvm_map_check(map, "map_findspace entry");
/*
* remember the original hint. if we are aligning, then we
* may have to try again with no alignment constraint if
* we fail the first time.
* Clamp the hint to the VM map's min/max address, and remmeber
* the clamped original hint. Remember the original hint,
* clamped to the min/max address. If we are aligning, then we
* may have to try again with no alignment constraint if we
* fail the first time.
*
* We use the original hint to verify later that the search has
* been monotonic -- that is, nonincreasing or nondecreasing,
* according to topdown or !topdown respectively. But the
* clamping is not monotonic.
*/
orig_hint = hint;
if (hint < vm_map_min(map)) { /* check ranges ... */
if (flags & UVM_FLAG_FIXED) {
UVMHIST_LOG(maphist,"<- VA below map range",0,0,0,0);
@ -1900,6 +1905,7 @@ uvm_map_findspace(struct vm_map *map, vaddr_t hint, vsize_t length,
hint, vm_map_min(map), vm_map_max(map), 0);
return (NULL);
}
orig_hint = hint;
/*
* hint may not be aligned properly; we need round up or down it