[PATCH bpf-next v3 0/5] bpf: fix stream capacity, read, and oversize handling

From: Jianlin Shi

Date: Sat Aug 15 2026 - 04:19:41 EST


v2 of the capacity-rollback fix was correct for bpf_stream_push_str(),
but review asked to:

1. refactor bpf_stream_release_capacity() to take a length;
2. fix the staging-path capacity leak and use vscnprintf();
3. return partial bpf_stream_read() progress on copy_to_user() fault;
4. reject truncated bpf_stream_vprintk() output with -E2BIG before
charging capacity;
5. add selftests for the oversize and straddling-buffer cases.

This series addresses those points.

Tested locally:
stream_oversize and stream_partial_read (equivalent to
./test_progs -t stream_oversize,stream_partial_read).

v2: https://lore.kernel.org/bpf/tencent_C919BB32458A4DAD645A68F441345B971E05@xxxxxx/
v1: https://lore.kernel.org/bpf/tencent_E69EAE29327E25B3548A9AF3F4FA289A6806@xxxxxx/

Jianlin Shi (5):
bpf: roll back stream capacity when allocation fails
bpf: fix stream capacity leak in staging path
bpf: return partial progress from bpf_stream_read on fault
bpf: reject oversized bpf_stream_vprintk output with -E2BIG
selftests/bpf: cover stream capacity and partial read edge cases

kernel/bpf/stream.c | 54 ++++++++------
.../testing/selftests/bpf/prog_tests/stream.c | 70 +++++++++++++++++++
tools/testing/selftests/bpf/progs/stream.c | 12 ++++
3 files changed, 116 insertions(+), 20 deletions(-)

--
2.43.0