Hi Jens, The patches in this series are what I came up with as the result of analyzing Alexander Potapenko's report about reading from null_blk. Please consider these patches for kernel v5.8. Thanks, Bart. Bart Van Assche (5): block: Fix type of first compat_put_{,u}long() argument bio.h: Declare the arguments of bio iteration functions const block: Document the bio_vec properties block: Fix zero_fill_bio() null_blk: Zero-initialize read buffers in non-memory-backed mode block/bio.c | 27 ++++++++++++++++++++++----- block/ioctl.c | 4 ++-- drivers/block/null_blk_main.c | 30 ++++++++++++++++++++++++++++++ include/linux/bio.h | 7 ++++--- include/linux/bvec.h | 18 ++++++++++++++++-- 5 files changed, 74 insertions(+), 12 deletions(-)