From df968c9329f6e5cf3596a0a54adb6f749747a746 Mon Sep 17 00:00:00 2001 From: Petr Vandrovec Date: Fri, 15 Sep 2017 02:15:05 -0500 Subject: [PATCH] objtool: Do not retrieve data from empty sections Binutils 2.29-9 in Debian return an error when elf_getdata is invoked on empty section (.note.GNU-stack in all kernel files), causing immediate failure of kernel build with: elf_getdata: can't manipulate null section As nothing is done with sections that have zero size, just do not retrieve their data at all. Signed-off-by: Petr Vandrovec Signed-off-by: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/2ce30a44349065b70d0f00e71e286dc0cbe745e6.1505459652.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar --- tools/objtool/elf.c | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-) diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c index 1e89a5f8bfc9..b4cd8bc62521 100644 --- a/tools/objtool/elf.c +++ b/tools/objtool/elf.c @@ -175,19 +175,20 @@ static int read_sections(struct elf *elf) return -1; } - sec->data = elf_getdata(s, NULL); - if (!sec->data) { - WARN_ELF("elf_getdata"); - return -1; - } - - if (sec->data->d_off != 0 || - sec->data->d_size != sec->sh.sh_size) { - WARN("unexpected data attributes for %s", sec->name); - return -1; + if (sec->sh.sh_size != 0) { + sec->data = elf_getdata(s, NULL); + if (!sec->data) { + WARN_ELF("elf_getdata"); + return -1; + } + if (sec->data->d_off != 0 || + sec->data->d_size != sec->sh.sh_size) { + WARN("unexpected data attributes for %s", + sec->name); + return -1; + } } - - sec->len = sec->data->d_size; + sec->len = sec->sh.sh_size; } /* sanity check, one more call to elf_nextscn() should return NULL */ -- 2.20.1