tools/build: Remove bpf() run-time check at build time

debian/changelog

@@ -5,6 +5,7 @@ linux-tools (4.5~rc4-1~exp1) UNRELEASED; urgency=medium
   [ Ben Hutchings ]
   * lockdep: Add missing macros
   * Adjust VPATH to work for check-hyperv (and simplify the modpost wrapper)
+  * tools/build: Remove bpf() run-time check at build time
 
  -- Ben Hutchings <ben@decadent.org.uk>  Thu, 18 Feb 2016 03:19:14 +0000
 

debian/patches/series

@@ -18,3 +18,4 @@ perf-fix-misleadingly-indented-assignment-whitespace.patch
 perf-tools-fix-unused-variables-x86_-32-64-_regoffse.patch
 revert-perf-tools-x86-build-perf-on-older-user-space.patch
 lockdep-add-missing-macros.patch
+tools-build-remove-bpf-run-time-check-at-build-time.patch

debian/patches/tools-build-remove-bpf-run-time-check-at-build-time.patch

@@ -0,0 +1,24 @@
+From: Ben Hutchings <ben@decadent.org.uk>
+Date: Sun, 21 Feb 2016 15:33:15 +0000
+Subject: tools/build: Remove bpf() run-time check at build time
+
+It is not correct to test that a syscall works on the build system's
+kernel.  We might be building on an earlier kernel version or with
+security restrictions that block bpf().
+
+Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
+---
+--- a/tools/build/feature/test-bpf.c
++++ b/tools/build/feature/test-bpf.c
+@@ -27,10 +27,5 @@ int main(void)
+ 	attr.log_level = 0;
+ 	attr.kern_version = 0;
+ 
+-	attr = attr;
+-	/*
+-	 * Test existence of __NR_bpf and BPF_PROG_LOAD.
+-	 * This call should fail if we run the testcase.
+-	 */
+-	return syscall(__NR_bpf, BPF_PROG_LOAD, attr, sizeof(attr));
++	return 0;
+ }