Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull objtool fix from Thomas Gleixner:
 "A single fix for objtool to address a bug in handling the cold
  subfunction detection for aliased functions which was added recently.
  The bug causes objtool to enter an infinite loop"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  objtool: Support GCC 8 '-fnoreorder-functions'

1 files changed, 28 insertions, 13 deletions

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 4e60e105583e..0d1acb704f64 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -302,19 +302,34 @@ static int read_symbols(struct elf *elf)
                                 continue;
                         sym->pfunc = sym->cfunc = sym;
                         coldstr = strstr(sym->name, ".cold.");
-                        if (coldstr) {
-                                coldstr[0] = '\0';
-                                pfunc = find_symbol_by_name(elf, sym->name);
-                                coldstr[0] = '.';
-
-                                if (!pfunc) {
-                                        WARN("%s(): can't find parent function",
-                                             sym->name);
-                                        goto err;
-                                }
-
-                                sym->pfunc = pfunc;
-                                pfunc->cfunc = sym;
+                        if (!coldstr)
+                                continue;
+
+                        coldstr[0] = '\0';
+                        pfunc = find_symbol_by_name(elf, sym->name);
+                        coldstr[0] = '.';
+
+                        if (!pfunc) {
+                                WARN("%s(): can't find parent function",
+                                     sym->name);
+                                goto err;
+                        }
+
+                        sym->pfunc = pfunc;
+                        pfunc->cfunc = sym;
+
+                        /*
+                         * Unfortunately, -fnoreorder-functions puts the child
+                         * inside the parent.  Remove the overlap so we can
+                         * have sane assumptions.
+                         *
+                         * Note that pfunc->len now no longer matches
+                         * pfunc->sym.st_size.
+                         */
+                        if (sym->sec == pfunc->sec &&
+                            sym->offset >= pfunc->offset &&
+                            sym->offset + sym->len == pfunc->offset + pfunc->len) {
+                                pfunc->len -= sym->len;
                         }
                 }
         }