This is a note to let you know that I've just added the patch titled
selftests/bpf: Define string const as global for test_sysctl_prog.c
to the 5.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
selftests-bpf-define-string-const-as-global-for-test.patch
and it can be found in the queue-5.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 7a8d5d373a15da2f2dc92e51538fe69d2978ff5d
Author: Yonghong Song <yhs@xxxxxx>
Date: Thu Sep 10 13:27:18 2020 -0700
selftests/bpf: Define string const as global for test_sysctl_prog.c
[ Upstream commit 6e057fc15a2da4ee03eb1fa6889cf687e690106e ]
When tweaking llvm optimizations, I found that selftest build failed
with the following error:
libbpf: elf: skipping unrecognized data section(6) .rodata.str1.1
libbpf: prog 'sysctl_tcp_mem': bad map relo against '.L__const.is_tcp_mem.tcp_mem_name'
in section '.rodata.str1.1'
Error: failed to open BPF object file: Relocation failed
make: *** [/work/net-next/tools/testing/selftests/bpf/test_sysctl_prog.skel.h] Error 255
make: *** Deleting file `/work/net-next/tools/testing/selftests/bpf/test_sysctl_prog.skel.h'
The local string constant "tcp_mem_name" is put into '.rodata.str1.1' section
which libbpf cannot handle. Using untweaked upstream llvm, "tcp_mem_name"
is completely inlined after loop unrolling.
Commit 7fb5eefd7639 ("selftests/bpf: Fix test_sysctl_loop{1, 2}
failure due to clang change") solved a similar problem by defining
the string const as a global. Let us do the same here
for test_sysctl_prog.c so it can weather future potential llvm changes.
Signed-off-by: Yonghong Song <yhs@xxxxxx>
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Acked-by: Andrii Nakryiko <andriin@xxxxxx>
Link: https://lore.kernel.org/bpf/20200910202718.956042-1-yhs@xxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/tools/testing/selftests/bpf/progs/test_sysctl_prog.c b/tools/testing/selftests/bpf/progs/test_sysctl_prog.c
index 50525235380e8..5489823c83fc2 100644
--- a/tools/testing/selftests/bpf/progs/test_sysctl_prog.c
+++ b/tools/testing/selftests/bpf/progs/test_sysctl_prog.c
@@ -19,11 +19,11 @@
#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
#endif
+const char tcp_mem_name[] = "net/ipv4/tcp_mem";
static __always_inline int is_tcp_mem(struct bpf_sysctl *ctx)
{
- char tcp_mem_name[] = "net/ipv4/tcp_mem";
unsigned char i;
- char name[64];
+ char name[sizeof(tcp_mem_name)];
int ret;
memset(name, 0, sizeof(name));
