From 1c47c8758a11345ac643fa68cb70b708a6668883 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Wed, 12 Apr 2023 16:49:37 -0700 Subject: [PATCH] objtool: Include weak functions in global_noreturns check If a global function doesn't return, and its prototype has the __noreturn attribute, its weak counterpart must also not return so that it matches the prototype and meets call site expectations. To properly follow the compiled control flow at the call sites, change the global_noreturns check to include both global and weak functions. On the other hand, if a weak function isn't in global_noreturns, assume the prototype doesn't have __noreturn. Even if the weak function doesn't return, call sites treat it like a returnable function. Fixes the following warning: kernel/sched/build_policy.o: warning: objtool: do_idle() falls through to next function play_idle_precise() Reported-by: kernel test robot Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Miroslav Benes Link: https://lore.kernel.org/r/ede3460d63f4a65d282c86f1175bd2662c2286ba.1681342859.git.jpoimboe@kernel.org --- tools/objtool/check.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 8d073bfd7d7fa..ae0c94285124b 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -236,14 +236,14 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func, if (!func) return false; - if (func->bind == STB_WEAK) - return false; - - if (func->bind == STB_GLOBAL) + if (func->bind == STB_GLOBAL || func->bind == STB_WEAK) for (i = 0; i < ARRAY_SIZE(global_noreturns); i++) if (!strcmp(func->name, global_noreturns[i])) return true; + if (func->bind == STB_WEAK) + return false; + if (!func->len) return false; -- 2.30.2