Messages in this thread | | | From | Arnd Bergmann <> | Date | Mon, 17 Jun 2019 16:04:14 +0200 | Subject | Re: [BUG]: mm/vmalloc: uninitialized variable access in pcpu_get_vm_areas |
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On Mon, Jun 17, 2019 at 3:49 PM Roman Penyaev <rpenyaev@suse.de> wrote: > > augment_tree_propagate_from(va); > > > > - if (type == NE_FIT_TYPE) > > - insert_vmap_area_augment(lva, &va->rb_node, > > - &free_vmap_area_root, &free_vmap_area_list); > > - } > > - > > return 0; > > } > > > Hi Arnd, > > Seems the proper fix is just setting lva to NULL. The only place > where lva is allocated and then used is when type == NE_FIT_TYPE, > so according to my shallow understanding of the code everything > should be fine.
I don't see how NULL could work here. insert_vmap_area_augment() passes the va pointer into find_va_links() and link_va(), both of which dereference the pointer, see
static void insert_vmap_area_augment(struct vmap_area *va, struct rb_node *from, struct rb_root *root, struct list_head *head) { struct rb_node **link; struct rb_node *parent;
if (from) link = find_va_links(va, NULL, from, &parent); else link = find_va_links(va, root, NULL, &parent);
link_va(va, root, parent, link, head); augment_tree_propagate_from(va); }
static __always_inline struct rb_node ** find_va_links(struct vmap_area *va, struct rb_root *root, struct rb_node *from, struct rb_node **parent) { ... if (va->va_start < tmp_va->va_end && va->va_end <= tmp_va->va_start) ... }
static __always_inline void link_va(struct vmap_area *va, struct rb_root *root, struct rb_node *parent, struct rb_node **link, struct list_head *head) { ... rb_link_node(&va->rb_node, parent, link); ... }
Arnd
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