This macro adds some debug code to check that the augment tree is maintained correctly, meaning that every node contains valid subtree_max_size value.
By default this option is set to 0 and not active. It requires recompilation of the kernel to activate it. Set to 1, compile the kernel. Signed-off-by: Uladzislau Rezki (Sony) <[email protected]> --- mm/vmalloc.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 3adbad3fb6c1..1449a8c43aa2 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -322,6 +322,8 @@ unsigned long vmalloc_to_pfn(const void *vmalloc_addr) EXPORT_SYMBOL(vmalloc_to_pfn); /*** Global kva allocator ***/ +#define DEBUG_AUGMENT_PROPAGATE_CHECK 0 + #define VM_LAZY_FREE 0x02 #define VM_VM_AREA 0x04 @@ -544,6 +546,53 @@ __unlink_va(struct vmap_area *va, struct rb_root *root) } } +#if DEBUG_AUGMENT_PROPAGATE_CHECK +static void +augment_tree_propagate_do_check(struct rb_node *n) +{ + struct vmap_area *va; + struct rb_node *node; + unsigned long size; + bool found = false; + + if (n == NULL) + return; + + va = rb_entry(n, struct vmap_area, rb_node); + size = va->subtree_max_size; + node = n; + + while (node) { + va = rb_entry(node, struct vmap_area, rb_node); + + if (get_subtree_max_size(node->rb_left) == size) { + node = node->rb_left; + } else { + if (__va_size(va) == size) { + found = true; + break; + } + + node = node->rb_right; + } + } + + if (!found) { + va = rb_entry(n, struct vmap_area, rb_node); + pr_emerg("tree is corrupted: %lu, %lu\n", + __va_size(va), va->subtree_max_size); + } + + augment_tree_propagate_do_check(n->rb_left); + augment_tree_propagate_do_check(n->rb_right); +} + +static void augment_tree_propagate_from_check(void) +{ + augment_tree_propagate_do_check(free_vmap_area_root.rb_node); +} +#endif + /* * This function populates subtree_max_size from bottom to upper * levels starting from VA point. The propagation must be done @@ -593,6 +642,10 @@ __augment_tree_propagate_from(struct vmap_area *va) va->subtree_max_size = new_va_sub_max_size; node = rb_parent(&va->rb_node); } + +#if DEBUG_AUGMENT_PROPAGATE_CHECK + augment_tree_propagate_from_check(); +#endif } static void -- 2.11.0
