bpf: Fix stream capacity leak in staging path

bpf_stream_stage_printk() increments ss->len before pushing the
formatted string to the staging log. If element allocation fails,
ss->len remains inflated and bpf_stream_stage_commit() permanently
charges the stream capacity for data that was never queued.

Only account the string length after a successful push, and use
vscnprintf() so the staged length is the truncated payload without
the trailing NUL.

Fixes: 5ab154f1463a ("bpf: Introduce BPF standard streams")
Signed-off-by: Jianlin Shi <shijianlin11@foxmail.com>
Link: https://lore.kernel.org/r/46898fb1ae482b2f8b1da459922b187378dfdc1d.1787492521.git.shijianlin11@foxmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

0 files changed, 0 insertions, 0 deletions