s390/mm: Add NULL pointer check to crst_table_free() base_crst_free()

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 <[email protected]> Fixes: 6326c26 ("s390: convert various pgalloc functions to use ptdescs") Signed-off-by: Heiko Carstens <[email protected]> Acked-by: Alexander Gordeev <[email protected]> Cc: [email protected] Signed-off-by: Linus Torvalds <[email protected]>
mj22226 · Jul 9, 2024 · b5efb63 · b5efb63
1 parent 4376e96
commit b5efb63
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/arch/s390/mm/pgalloc.c b/arch/s390/mm/pgalloc.c
@@ -55,6 +55,8 @@ 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));
 }
 
@@ -262,6 +264,8 @@ 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));
 }