The generic_map_lookup_batch currently returns EINTR if it fails with ENOENT and retries several times on bpf_map_copy_value. The next batch would start from the same location, presuming it's a transient issue. This is incorrect if a map can actually have "holes", i.e. "get_next_key" can return a key that does not point to a valid value. At least the array of maps type may contain such holes legitly. Right now these holes show up, generic batch lookup cannot proceed any more. It will always fail with EINTR errors.
This patch fixes this behavior by skipping the non-existing key, and does not return EINTR any more.
V2->V3: deleted a unused macro V1->V2: split the fix and selftests; fixed a few selftests issues.
V2: https://lore.kernel.org/bpf/cover.1738905497.git.yan@cloudflare.com/ V1: https://lore.kernel.org/bpf/Z6OYbS4WqQnmzi2z@debian.debian/
Yan Zhai (2): bpf: skip non exist keys in generic_map_lookup_batch selftests: bpf: test batch lookup on array of maps with holes
kernel/bpf/syscall.c | 18 ++---- .../bpf/map_tests/map_in_map_batch_ops.c | 62 +++++++++++++------ 2 files changed, 49 insertions(+), 31 deletions(-)