Merge branch 'bpf-fix-sysctl-new-value-handling-in-__cgroup_bpf_run_filter_sysctl'

Dawei Feng says:

====================
bpf: fix sysctl new-value handling in __cgroup_bpf_run_filter_sysctl

This series fixes three bugs in the sysctl write-buffer replacement path
of __cgroup_bpf_run_filter_sysctl(). It resolves a kvzalloc()/kfree()
mismatch, adds a missing NUL terminator to the replacement string, and
updates a stale return value check to safely restore the replacement
functionality.

Patch Summary:
- patch 1 NUL-terminates the replaced sysctl value
- patch 2 uses kvfree() for the replaced sysctl write buffer
- patch 3 restores sysctl new-value replacement

Changelog:
v2 -> v3:
- reordered patches 1 and 2
- added the missing Reviewed-by/Acked-by tags to patches 2 and 3
- fixed the incorrect Fixes tag in patch 3
- simplified the dynamic test logs in patch 1 and 2, and updated
  titles
====================

Link: https://patch.msgid.link/20260603105317.944304-1-dawei.feng@seu.edu.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>