bpf: Annotate bpf_obj_memcpy with data_race

syzbot reported KCSAN write-write races when two tasks concurrently
update the same map value. Both accesses reach the ordinary memcpy()
paths in bpf_obj_memcpy() through copy_map_value().

Unlocked in-place updates of published map values are intentionally not
serialized and may produce torn values. Callers requiring consistency
must provide synchronization appropriate for the map type.
bpf_long_memcpy() already annotates the same behavior for long-aligned
copies.

Annotate the ordinary memcpy() sites in bpf_obj_memcpy() with
data_race(), matching bpf_long_memcpy(). This documents the existing
concurrency semantics and suppresses KCSAN reports for these intentional
races without changing synchronization or map update behavior.

Reported-by: syzbot+44044637ef892e79ca2b@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=44044637ef892e79ca2b
Signed-off-by: Quanye Yang <quanyeyang@proton.me>
Link: https://lore.kernel.org/bpf/20260822-bpf-kcsan-obj-memcpy-v3-1-4227b2edd8b4@proton.me
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

0 files changed, 0 insertions, 0 deletions