From 794fa52b94637d6b2e8c9474fbe3983af5c9f046 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Tue, 9 Jul 2024 08:50:56 +0200 Subject: [PATCH] s390/mm: Add NULL pointer check to crst_table_free() base_crst_free() commit b5efb63acf7bddaf20eacfcac654c25c446eabe8 upstream. crst_table_free() used to work with NULL pointers before the conversion to ptdescs. Since crst_table_free() can be called with a NULL pointer (error handling in crst_table_upgrade() add an explicit check. Also add the same check to base_crst_free() for consistency reasons. In real life this should not happen, since order two GFP_KERNEL allocations will not fail, unless FAIL_PAGE_ALLOC is enabled and used. Reported-by: Yunseong Kim Fixes: 6326c26c1514 ("s390: convert various pgalloc functions to use ptdescs") Signed-off-by: Heiko Carstens Acked-by: Alexander Gordeev Cc: stable@kernel.org Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- arch/s390/mm/pgalloc.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/s390/mm/pgalloc.c b/arch/s390/mm/pgalloc.c index 6396d6b06a3a..9355fbe5f51e 100644 --- a/arch/s390/mm/pgalloc.c +++ b/arch/s390/mm/pgalloc.c @@ -53,6 +53,8 @@ unsigned long *crst_table_alloc(struct mm_struct *mm) void crst_table_free(struct mm_struct *mm, unsigned long *table) { + if (!table) + return; pagetable_free(virt_to_ptdesc(table)); } @@ -500,6 +502,8 @@ static unsigned long *base_crst_alloc(unsigned long val) static void base_crst_free(unsigned long *table) { + if (!table) + return; pagetable_free(virt_to_ptdesc(table)); }