From: KP Singh <kpsingh@kernel.org>
Date: Mon, 7 Mar 2022 13:30:47 +0000
Subject: bpf/docs: Update vmtest docs for static linking
Patch-mainline: v5.18-rc1
Git-commit: 5ad0a415da6be8c13ed45c655e5acc9fa93557a9
References: jsc#PED-1377

Dynamic linking when compiling on the host can cause issues when the
libc version does not match the one in the VM image. Update the
docs to explain how to do this.

Before:
  ./vmtest.sh -- ./test_progs -t test_ima
  ./test_progs: /usr/lib/libc.so.6: version `GLIBC_2.33' not found (required by ./test_progs)

After:

  LDLIBS=-static ./vmtest.sh -- ./test_progs -t test_ima
  test_ima:OK
  Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED

Reported-by: "Geyslan G. Bem" <geyslan@gmail.com>
Signed-off-by: KP Singh <kpsingh@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220307133048.1287644-1-kpsingh@kernel.org
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
 tools/testing/selftests/bpf/README.rst |    8 ++++++++
 1 file changed, 8 insertions(+)

--- a/tools/testing/selftests/bpf/README.rst
+++ b/tools/testing/selftests/bpf/README.rst
@@ -32,6 +32,14 @@ For more information on about using the
 
   $ tools/testing/selftests/bpf/vmtest.sh -h
 
+In case of linker errors when running selftests, try using static linking:
+
+.. code-block:: console
+
+  $ LDLIBS=-static vmtest.sh
+
+.. note:: Some distros may not support static linking.
+
 .. note:: The script uses pahole and clang based on host environment setting.
           If you want to change pahole and llvm, you can change `PATH` environment
           variable in the beginning of script.