@@ -393,19 +393,20 @@ static bool find_aligned_area(struct ma_state *mas, unsigned long section_size,
static int vm_module_tags_populate(void)
{
- unsigned long phys_size = vm_module_tags->nr_pages << PAGE_SHIFT;
+ unsigned long phys_end = ALIGN_DOWN(module_tags.start_addr, PAGE_SIZE) +
+ (vm_module_tags->nr_pages << PAGE_SHIFT);
+ unsigned long new_end = module_tags.start_addr + module_tags.size;
- if (phys_size < module_tags.size) {
+ if (phys_end < new_end) {
struct page **next_page = vm_module_tags->pages + vm_module_tags->nr_pages;
- unsigned long addr = module_tags.start_addr + phys_size;
unsigned long more_pages;
unsigned long nr;
- more_pages = ALIGN(module_tags.size - phys_size, PAGE_SIZE) >> PAGE_SHIFT;
+ more_pages = ALIGN(new_end - phys_end, PAGE_SIZE) >> PAGE_SHIFT;
nr = alloc_pages_bulk_array_node(GFP_KERNEL | __GFP_NOWARN,
NUMA_NO_NODE, more_pages, next_page);
if (nr < more_pages ||
- vmap_pages_range(addr, addr + (nr << PAGE_SHIFT), PAGE_KERNEL,
+ vmap_pages_range(phys_end, phys_end + (nr << PAGE_SHIFT), PAGE_KERNEL,
next_page, PAGE_SHIFT) < 0) {
/* Clean up and error out */
for (int i = 0; i < nr; i++)
vm_module_tags_populate() calculation of the populated area assumes that area starts at a page boundary and therefore when new pages are allocation, the end of the area is page-aligned as well. If the start of the area is not page-aligned then allocating a page and incrementing the end of the area by PAGE_SIZE leads to an area at the end but within the area boundary which is not populated. Accessing this are will lead to a kernel panic. Fix the calculation by down-aligning the start of the area and using that as the location allocated pages are mapped to. Fixes: 0f9b685626da ("alloc_tag: populate memory for module tags as needed") Reported-by: kernel test robot <oliver.sang@intel.com> Closes: https://lore.kernel.org/oe-lkp/202411132111.6a221562-lkp@intel.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> --- Applies over mm-unstable lib/alloc_tag.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) base-commit: 539cd49425a4e9a66d601d9a8124f5c70e238d56