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 <petr@vandrovec.name>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/2ce30a44349065b70d0f00e71e286dc0cbe745e6.1505459652.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Petr Vandrovec 2017-09-15 02:15:05 -05:00 committed by Ingo Molnar
parent 0998b7a0be
commit df968c9329
1 changed files with 13 additions and 12 deletions

View File

@ -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->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;
}
}
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 */