The patch titled Subject: alloc_tag: fix module allocation tags populated area calculation has been added to the -mm mm-hotfixes-unstable branch. Its filename is alloc_tag-fix-module-allocation-tags-populated-area-calculation.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: Suren Baghdasaryan surenb@google.com Subject: alloc_tag: fix module allocation tags populated area calculation Date: Fri, 29 Nov 2024 16:14:22 -0800

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.

Link: https://lkml.kernel.org/r/20241130001423.1114965-1-surenb@google.com Fixes: 0f9b685626da ("alloc_tag: populate memory for module tags as needed") Signed-off-by: Suren Baghdasaryan surenb@google.com Reported-by: kernel test robot oliver.sang@intel.com Closes: https://lore.kernel.org/oe-lkp/202411132111.6a221562-lkp@intel.com Cc: David Wang 00107082@163.com Cc: Kent Overstreet kent.overstreet@linux.dev Cc: Mike Rapoport (Microsoft) rppt@kernel.org Cc: Pasha Tatashin pasha.tatashin@soleen.com Cc: Sourav Panda souravpanda@google.com Cc: Yu Zhao yuzhao@google.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

lib/alloc_tag.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)

--- a/lib/alloc_tag.c~alloc_tag-fix-module-allocation-tags-populated-area-calculation +++ a/lib/alloc_tag.c @@ -401,19 +401,20 @@ repeat:

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++) _

Patches currently in -mm which might be from surenb@google.com are

alloc_tag-fix-module-allocation-tags-populated-area-calculation.patch alloc_tag-fix-set_codetag_empty-when-config_mem_alloc_profiling_debug.patch mm-convert-mm_lock_seq-to-a-proper-seqcount.patch mm-introduce-mmap_lock_speculation_beginend.patch