Re: [PATCH v2] powerpc/mm: Fix null-pointer dereference in pgtable_cache_add
From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2023-12-01 10:17:34
Also in:
lkml
From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2023-12-01 10:17:34
Also in:
lkml
Kunwu Chan [off-list ref] writes:
kasprintf() returns a pointer to dynamically allocated memory which can be NULL upon failure. Ensure the allocation was successful by checking the pointer validity. Suggested-by: Christophe Leroy <redacted> Suggested-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Kunwu Chan <redacted> --- v2: Use "panic" instead of "return" --- arch/powerpc/mm/init-common.c | 2 ++ 1 file changed, 2 insertions(+)diff --git a/arch/powerpc/mm/init-common.c b/arch/powerpc/mm/init-common.c index 119ef491f797..9788950b33f5 100644 --- a/arch/powerpc/mm/init-common.c +++ b/arch/powerpc/mm/init-common.c@@ -139,6 +139,8 @@ void pgtable_cache_add(unsigned int shift) align = max_t(unsigned long, align, minalign); name = kasprintf(GFP_KERNEL, "pgtable-2^%d", shift); + if (!name) + panic("Failed to allocate memory for order %d", shift); new = kmem_cache_create(name, table_size, align, 0, ctor(shift)); if (!new) panic("Could not allocate pgtable cache for order %d", shift);
It would be nice to avoid two calls to panic. Can you reorganise the logic so that there's only one? Initialising new to NULL might help. cheers