The quilt patch titled
Subject: alloc_tag: fix module allocation tags populated area calculation
has been removed from the -mm tree. Its filename was
alloc_tag-fix-module-allocation-tags-populated-area-calculation.patch
This patch was dropped because it was merged into the mm-hotfixes-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Suren Baghdasaryan <surenb@xxxxxxxxxx>
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.
[gehao@xxxxxxxxxx: fix vm_module_tags_populate's KASAN poisoning logic]
Link: https://lkml.kernel.org/r/20241205170528.81000-1-hao.ge@xxxxxxxxx
[gehao@xxxxxxxxxx: fix panic when CONFIG_KASAN enabled and CONFIG_KASAN_VMALLOC not enabled]
Link: https://lkml.kernel.org/r/20241212072126.134572-1-hao.ge@xxxxxxxxx
Link: https://lkml.kernel.org/r/20241130001423.1114965-1-surenb@xxxxxxxxxx
Fixes: 0f9b685626da ("alloc_tag: populate memory for module tags as needed")
Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
Closes: https://lore.kernel.org/oe-lkp/202411132111.6a221562-lkp@xxxxxxxxx
Acked-by: Yu Zhao <yuzhao@xxxxxxxxxx>
Tested-by: Adrian Huang <ahuang12@xxxxxxxxxx>
Cc: David Wang <00107082@xxxxxxx>
Cc: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Cc: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
Cc: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Sourav Panda <souravpanda@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/alloc_tag.c | 34 +++++++++++++++++++++++++++++-----
1 file changed, 29 insertions(+), 5 deletions(-)
--- a/lib/alloc_tag.c~alloc_tag-fix-module-allocation-tags-populated-area-calculation
+++ a/lib/alloc_tag.c
@@ -408,28 +408,52 @@ 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 old_shadow_end = ALIGN(phys_end, MODULE_ALIGN);
+ unsigned long new_shadow_end = ALIGN(new_end, MODULE_ALIGN);
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++)
__free_page(next_page[i]);
return -ENOMEM;
}
+
vm_module_tags->nr_pages += nr;
+
+ /*
+ * Kasan allocates 1 byte of shadow for every 8 bytes of data.
+ * When kasan_alloc_module_shadow allocates shadow memory,
+ * its unit of allocation is a page.
+ * Therefore, here we need to align to MODULE_ALIGN.
+ */
+ if (old_shadow_end < new_shadow_end)
+ kasan_alloc_module_shadow((void *)old_shadow_end,
+ new_shadow_end - old_shadow_end,
+ GFP_KERNEL);
}
+ /*
+ * Mark the pages as accessible, now that they are mapped.
+ * With hardware tag-based KASAN, marking is skipped for
+ * non-VM_ALLOC mappings, see __kasan_unpoison_vmalloc().
+ */
+ kasan_unpoison_vmalloc((void *)module_tags.start_addr,
+ new_end - module_tags.start_addr,
+ KASAN_VMALLOC_PROT_NORMAL);
+
return 0;
}
_
Patches currently in -mm which might be from surenb@xxxxxxxxxx are
seqlock-add-raw_seqcount_try_begin.patch
mm-convert-mm_lock_seq-to-a-proper-seqcount.patch
mm-introduce-mmap_lock_speculate_try_beginretry.patch
