[GIT PULL] core kernel fixes

From: Ingo Molnar
Date: Thu May 16 2019 - 11:53:51 EST


Linus,

Please pull the latest core-urgent-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git core-urgent-for-linus

# HEAD: 2decec48b0fd28ffdbf4cc684bd04e735f0839dd objtool: Fix whitelist documentation typo

A handful of objtool updates, plus a documentation addition for
__ab_c_size().

Thanks,

Ingo

------------------>
Josh Poimboeuf (2):
objtool: Don't use ignore flag for fake jumps
objtool: Fix function fallthrough detection

Raphael Gault (1):
objtool: Fix whitelist documentation typo

Rasmus Villemoes (1):
overflow.h: Add comment documenting __ab_c_size()


include/linux/overflow.h | 8 ++++++--
tools/objtool/Documentation/stack-validation.txt | 2 +-
tools/objtool/check.c | 11 +++++++----
3 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/include/linux/overflow.h b/include/linux/overflow.h
index 40b48e2133cb..6534a727cadb 100644
--- a/include/linux/overflow.h
+++ b/include/linux/overflow.h
@@ -278,11 +278,15 @@ static inline __must_check size_t array3_size(size_t a, size_t b, size_t c)
return bytes;
}

-static inline __must_check size_t __ab_c_size(size_t n, size_t size, size_t c)
+/*
+ * Compute a*b+c, returning SIZE_MAX on overflow. Internal helper for
+ * struct_size() below.
+ */
+static inline __must_check size_t __ab_c_size(size_t a, size_t b, size_t c)
{
size_t bytes;

- if (check_mul_overflow(n, size, &bytes))
+ if (check_mul_overflow(a, b, &bytes))
return SIZE_MAX;
if (check_add_overflow(bytes, c, &bytes))
return SIZE_MAX;
diff --git a/tools/objtool/Documentation/stack-validation.txt b/tools/objtool/Documentation/stack-validation.txt
index 3995735a878f..cd17ee022072 100644
--- a/tools/objtool/Documentation/stack-validation.txt
+++ b/tools/objtool/Documentation/stack-validation.txt
@@ -306,7 +306,7 @@ ignore it:

- To skip validation of a file, add

- OBJECT_FILES_NON_STANDARD_filename.o := n
+ OBJECT_FILES_NON_STANDARD_filename.o := y

to the Makefile.

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index ac743a1d53ab..7325d89ccad9 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -28,6 +28,8 @@
#include <linux/hashtable.h>
#include <linux/kernel.h>

+#define FAKE_JUMP_OFFSET -1
+
struct alternative {
struct list_head list;
struct instruction *insn;
@@ -568,7 +570,7 @@ static int add_jump_destinations(struct objtool_file *file)
insn->type != INSN_JUMP_UNCONDITIONAL)
continue;

- if (insn->ignore)
+ if (insn->ignore || insn->offset == FAKE_JUMP_OFFSET)
continue;

rela = find_rela_by_dest_range(insn->sec, insn->offset,
@@ -745,10 +747,10 @@ static int handle_group_alt(struct objtool_file *file,
clear_insn_state(&fake_jump->state);

fake_jump->sec = special_alt->new_sec;
- fake_jump->offset = -1;
+ fake_jump->offset = FAKE_JUMP_OFFSET;
fake_jump->type = INSN_JUMP_UNCONDITIONAL;
fake_jump->jump_dest = list_next_entry(last_orig_insn, list);
- fake_jump->ignore = true;
+ fake_jump->func = orig_insn->func;
}

if (!special_alt->new_len) {
@@ -1957,7 +1959,8 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
return 1;
}

- func = insn->func ? insn->func->pfunc : NULL;
+ if (insn->func)
+ func = insn->func->pfunc;

if (func && insn->ignore) {
WARN_FUNC("BUG: why am I validating an ignored function?",