From 9f6c6ad161f1af37548a6b80fb15710998ccfd1e Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes Date: Wed, 24 May 2023 09:24:24 +0100 Subject: lib/test_vmalloc.c: avoid garbage in page array 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@gmail.com Fixes: 869cb29a61a1 ("lib/test_vmalloc.c: add vm_map_ram()/vm_unmap_ram() test case") Signed-off-by: Lorenzo Stoakes Reviewed-by: Uladzislau Rezki (Sony) Reviewed-by: Baoquan He Cc: Christoph Hellwig Signed-off-by: Andrew Morton --- lib/test_vmalloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'lib/test_vmalloc.c') diff --git a/lib/test_vmalloc.c b/lib/test_vmalloc.c index 9dd9745d365f..3718d9886407 100644 --- a/lib/test_vmalloc.c +++ b/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; -- cgit