If you try to store u64 in a kfifo (or a struct with u64 members), then the buf member of __STRUCT_KFIFO_PTR will cause 4 bytes padding due to alignment (note that struct __kfifo is 20 bytes on 32 bit).
That in turn causes the __is_kfifo_ptr() to fail, which is caught by kfifo_alloc(), which now returns EINVAL. So, ensure that __is_kfifo_ptr() compares to the right structure. Signed-off-by: Sean Young <s...@mess.org> Acked-by: Stefani Seibold <stef...@seibold.net> --- include/linux/kfifo.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h index 41eb6fdf87a8..86b5fb08e96c 100644 --- a/include/linux/kfifo.h +++ b/include/linux/kfifo.h @@ -113,7 +113,8 @@ struct kfifo_rec_ptr_2 __STRUCT_KFIFO_PTR(unsigned char, 2, void); * array is a part of the structure and the fifo type where the array is * outside of the fifo structure. */ -#define __is_kfifo_ptr(fifo) (sizeof(*fifo) == sizeof(struct __kfifo)) +#define __is_kfifo_ptr(fifo) \ + (sizeof(*fifo) == sizeof(STRUCT_KFIFO_PTR(typeof(*(fifo)->type)))) /** * DECLARE_KFIFO_PTR - macro to declare a fifo pointer object -- 2.13.6
