From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7EFE5C2B9F4 for ; Fri, 25 Jun 2021 13:38:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5FCDD616E8 for ; Fri, 25 Jun 2021 13:38:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230112AbhFYNkt (ORCPT ); Fri, 25 Jun 2021 09:40:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:44874 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229498AbhFYNks (ORCPT ); Fri, 25 Jun 2021 09:40:48 -0400 Received: from oasis.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 917446197C; Fri, 25 Jun 2021 13:38:26 +0000 (UTC) Date: Fri, 25 Jun 2021 09:38:24 -0400 From: Steven Rostedt To: Peter Zijlstra Cc: jpoimboe@redhat.com, tglx@linutronix.de, linux-kernel@vger.kernel.org, joro@8bytes.org, boris.ostrovsky@oracle.com, jgross@suse.com, x86@kernel.org, mbenes@suse.com, dvyukov@google.com, elver@google.com Subject: Re: [PATCH v2 03/24] objtool: Handle __sanitize_cov*() tail calls Message-ID: <20210625093824.03eb3cf7@oasis.local.home> In-Reply-To: <20210624095147.818783799@infradead.org> References: <20210624094059.886075998@infradead.org> <20210624095147.818783799@infradead.org> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 24 Jun 2021 11:41:02 +0200 Peter Zijlstra wrote: > +static void add_call_dest(struct objtool_file *file, struct instruction *insn, > + struct symbol *dest, bool sibling) > +{ > + struct reloc *reloc = insn_reloc(file, insn); > + > + insn->call_dest = dest; > + if (!dest) > + return; > + > + if (insn->call_dest->static_call_tramp) { > + list_add_tail(&insn->call_node, > + &file->static_call_list); > + } > + > + if (insn->sec->noinstr && > + !strncmp(insn->call_dest->name, "__sanitizer_cov_", 16)) { > + if (reloc) { > + reloc->type = R_NONE; > + elf_write_reloc(file->elf, reloc); > + } > + > + elf_write_insn(file->elf, insn->sec, > + insn->offset, insn->len, > + sibling ? arch_ret_insn(insn->len) > + : arch_nop_insn(insn->len)); > + > + insn->type = sibling ? INSN_RETURN : INSN_NOP; > + } > + > + if (mcount && !strcmp(insn->call_dest->name, "__fentry__")) { > + if (sibling) > + WARN_FUNC("Tail call to __fentry__ !?!?", insn->sec, insn->offset); Have you ever triggered the above? -- Steve > + > + if (reloc) { > + reloc->type = R_NONE; > + elf_write_reloc(file->elf, reloc); > + } > +