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process/vm: fix lookup_process_memory_range (again)

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That optimistically going left was a more serious bug than just
last iteration, we could just pass by a match and continue down
the tree if the match was not a leaf.

Fix the actual algorithm issue

Conflicts:
	kernel/process.c
This commit is contained in:
Dominique Martinet
2017-09-22 10:06:59 +09:00
committed by Balazs Gerofi
parent 67529f21ff
commit d23939da8c
1 changed files with 1 additions and 6 deletions
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7
kernel/process.c
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@@ -1293,7 +1293,7 @@ struct vm_range *lookup_process_memory_range(
int i; int i;
struct vm_range *range = NULL, *match = NULL; struct vm_range *range = NULL, *match = NULL;
struct rb_root *root = &vm->vm_range_tree; struct rb_root *root = &vm->vm_range_tree;
struct rb_node *node = root->rb_node, *prev = NULL; struct rb_node *node = root->rb_node;
dkprintf("lookup_process_memory_range(%p,%lx,%lx)\n", vm, start, end); dkprintf("lookup_process_memory_range(%p,%lx,%lx)\n", vm, start, end);
@@ -1312,7 +1312,6 @@ struct vm_range *lookup_process_memory_range(
} }
while (node) { while (node) {
prev = node;
range = rb_entry(node, struct vm_range, vm_rb_node); range = rb_entry(node, struct vm_range, vm_rb_node);
if (end <= range->start) { if (end <= range->start) {
node = node->rb_left; node = node->rb_left;
@@ -1329,10 +1328,6 @@ struct vm_range *lookup_process_memory_range(
} }
} }
/* We optimistically try to go left, go back if we went too far */
if (!node && range && start < range->end)
node = prev;
if (match && end > match->start) { if (match && end > match->start) {
vm->range_cache_ind = (vm->range_cache_ind - 1 + VM_RANGE_CACHE_SIZE) vm->range_cache_ind = (vm->range_cache_ind - 1 + VM_RANGE_CACHE_SIZE)
% VM_RANGE_CACHE_SIZE; % VM_RANGE_CACHE_SIZE;