On Mon, Jul 01, 2024 at 01:59:03PM +0800, Shung-Hsi Yu wrote: > This patch set refactors kernel/bpf/verifier.c to use type-agnostic, > generic overflow-check helpers defined in include/linux/overflow.h to > check for addition and subtraction overflow, and drop the > signed_*_overflows() helpers we currently have in kernel/bpf/verifier.c. > There should be no functional change in how the verifier works. > > The main motivation is to make future refactoring[1] easier. > > While check_mul_overflow() also exists and could potentially replace what > we have in scalar*_min_max_mul(), it does not help with refactoring and > would either change how the verifier works (e.g. lifting restriction on > umax<=U32_MAX and u32_max<=U16_MAX) or make the code slightly harder to > read, so it is left for future endeavour. > > Changes from v1 <https://lore.kernel.org/r/20240623070324.12634-1-shung-hsi.yu@xxxxxxxx>: > - use pointers to values in dst_reg directly as the sum/diff pointer and > remove the else branch (Jiri) > - change local variables to be dst_reg pointers instead of src_reg values > - include comparison of generated assembly before & after the change > (Alexei) > > 1: https://github.com/kernel-patches/bpf/pull/7205/commits CI failed, but it looks like aws hiccup: https://github.com/kernel-patches/bpf/actions/runs/9739067425/job/26873810583 lgtm Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx> jirka > > Shung-Hsi Yu (2): > bpf: use check_add_overflow() to check for addition overflows > bpf: use check_sub_overflow() to check for subtraction overflows > > kernel/bpf/verifier.c | 151 ++++++++++++------------------------------ > 1 file changed, 42 insertions(+), 109 deletions(-) > > -- > 2.45.2 >
