If vm_map_protect fails with KERN_RESOURCE_SHORTAGE, be sure to
simplify modified entries before returning. Reviewed by: alc, markj (earlier version), kib (earlier version) Approved by: kib, markj (mentors, implicit) Differential Revision: https://reviews.freebsd.org/D20753
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parent
a852cb9596
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a72dce340d
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=349498
@ -2454,6 +2454,7 @@ vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end,
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vm_object_t obj;
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vm_object_t obj;
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struct ucred *cred;
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struct ucred *cred;
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vm_prot_t old_prot;
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vm_prot_t old_prot;
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int rv;
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if (start == end)
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if (start == end)
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return (KERN_SUCCESS);
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return (KERN_SUCCESS);
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@ -2508,10 +2509,13 @@ vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end,
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}
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}
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/*
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/*
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* Do an accounting pass for private read-only mappings that
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* Before changing the protections, try to reserve swap space for any
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* now will do cow due to allowed write (e.g. debugger sets
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* private (i.e., copy-on-write) mappings that are transitioning from
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* breakpoint on text segment)
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* read-only to read/write access. If a reservation fails, break out
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* of this loop early and let the next loop simplify the entries, since
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* some may now be mergeable.
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*/
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*/
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rv = KERN_SUCCESS;
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vm_map_clip_start(map, entry, start);
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vm_map_clip_start(map, entry, start);
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for (current = entry; current->start < end; current = current->next) {
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for (current = entry; current->start < end; current = current->next) {
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@ -2529,8 +2533,9 @@ vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end,
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if (obj == NULL || (current->eflags & MAP_ENTRY_NEEDS_COPY)) {
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if (obj == NULL || (current->eflags & MAP_ENTRY_NEEDS_COPY)) {
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if (!swap_reserve(current->end - current->start)) {
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if (!swap_reserve(current->end - current->start)) {
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vm_map_unlock(map);
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rv = KERN_RESOURCE_SHORTAGE;
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return (KERN_RESOURCE_SHORTAGE);
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end = current->end;
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break;
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}
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}
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crhold(cred);
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crhold(cred);
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current->cred = cred;
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current->cred = cred;
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@ -2553,8 +2558,9 @@ vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end,
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obj, current));
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obj, current));
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if (!swap_reserve(ptoa(obj->size))) {
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if (!swap_reserve(ptoa(obj->size))) {
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VM_OBJECT_WUNLOCK(obj);
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VM_OBJECT_WUNLOCK(obj);
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vm_map_unlock(map);
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rv = KERN_RESOURCE_SHORTAGE;
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return (KERN_RESOURCE_SHORTAGE);
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end = current->end;
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break;
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}
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}
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crhold(cred);
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crhold(cred);
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@ -2564,11 +2570,14 @@ vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end,
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}
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}
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/*
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/*
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* Go back and fix up protections. [Note that clipping is not
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* If enough swap space was available, go back and fix up protections.
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* necessary the second time.]
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* Otherwise, just simplify entries, since some may have been modified.
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* [Note that clipping is not necessary the second time.]
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*/
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*/
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for (current = entry; current->start < end; current = current->next) {
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for (current = entry; current->start < end;
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if ((current->eflags & MAP_ENTRY_GUARD) != 0)
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vm_map_simplify_entry(map, current), current = current->next) {
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if (rv != KERN_SUCCESS ||
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(current->eflags & MAP_ENTRY_GUARD) != 0)
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continue;
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continue;
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old_prot = current->protection;
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old_prot = current->protection;
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@ -2603,10 +2612,9 @@ vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end,
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current->protection & MASK(current));
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current->protection & MASK(current));
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#undef MASK
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#undef MASK
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}
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}
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vm_map_simplify_entry(map, current);
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}
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}
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vm_map_unlock(map);
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vm_map_unlock(map);
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return (KERN_SUCCESS);
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return (rv);
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}
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}
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/*
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/*
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