Commit b5efb63a authored Jul 09, 2024 by Heiko Carstens Committed by Linus Torvalds Jul 09, 2024

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 <yskelg@gmail.com>
Fixes: 6326c26c ("s390: convert various pgalloc functions to use ptdescs")
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 4376e966

arch/s390/mm/pgalloc.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -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));
		}