The quilt patch titled
Subject: lib/test_vmalloc.c: avoid garbage in page array
has been removed from the -mm tree. Its filename was
lib-test_vmallocc-avoid-garbage-in-page-array.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: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Subject: lib/test_vmalloc.c: avoid garbage in page array
Date: Wed, 24 May 2023 09:24:24 +0100
It turns out that alloc_pages_bulk_array() does not treat the page_array
parameter as an output parameter, but rather reads the array and skips any
entries that have already been allocated.
This is somewhat unexpected and breaks this test, as we allocate the pages
array uninitialised on the assumption it will be overwritten.
As a result, the test was referencing uninitialised data and causing the
PFN to not be valid and thus a WARN_ON() followed by a null pointer deref
and panic.
In addition, this is an array of pointers not of struct page objects, so we
need only allocate an array with elements of pointer size.
We solve both problems by simply using kcalloc() and referencing
sizeof(struct page *) rather than sizeof(struct page).
Link: https://lkml.kernel.org/r/20230524082424.10022-1-lstoakes@xxxxxxxxx
Fixes: 869cb29a61a1 ("lib/test_vmalloc.c: add vm_map_ram()/vm_unmap_ram() test case")
Signed-off-by: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
Reviewed-by: Baoquan He <bhe@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/test_vmalloc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/lib/test_vmalloc.c~lib-test_vmallocc-avoid-garbage-in-page-array
+++ a/lib/test_vmalloc.c
@@ -369,7 +369,7 @@ vm_map_ram_test(void)
int i;
map_nr_pages = nr_pages > 0 ? nr_pages:1;
- pages = kmalloc(map_nr_pages * sizeof(struct page), GFP_KERNEL);
+ pages = kcalloc(map_nr_pages, sizeof(struct page *), GFP_KERNEL);
if (!pages)
return -1;
_
Patches currently in -mm which might be from lstoakes@xxxxxxxxx are
mm-vmalloc-do-not-output-a-spurious-warning-when-huge-vmalloc-fails.patch
mm-mmap-separate-writenotify-and-dirty-tracking-logic.patch
mm-gup-disallow-foll_longterm-gup-nonfast-writing-to-file-backed-mappings.patch
mm-gup-disallow-foll_longterm-gup-fast-writing-to-file-backed-mappings.patch
mm-gup-add-missing-gup_must_unshare-check-to-gup_huge_pgd.patch
mm-gup-remove-unused-vmas-parameter-from-get_user_pages.patch
mm-gup-remove-unused-vmas-parameter-from-pin_user_pages_remote.patch
mm-gup-remove-vmas-parameter-from-get_user_pages_remote.patch
io_uring-rsrc-delegate-vma-file-backed-check-to-gup.patch
mm-gup-remove-vmas-parameter-from-pin_user_pages.patch
mm-gup-remove-vmas-array-from-internal-gup-functions.patch
mm-mmap-refactor-mlock_future_check.patch
mm-vmalloc-dont-purge-usable-blocks-unnecessarily-fix.patch
