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=-16.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 10671C2B9F4 for ; Mon, 28 Jun 2021 13:43:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E76E761C76 for ; Mon, 28 Jun 2021 13:43:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232053AbhF1NqH (ORCPT ); Mon, 28 Jun 2021 09:46:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:46270 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230164AbhF1NqF (ORCPT ); Mon, 28 Jun 2021 09:46:05 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id E2B9C61883; Mon, 28 Jun 2021 13:43:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1624887820; bh=gJqInbHX6Us83HMFo3RkNrKg8rMfR8eHVqFlvzvL8VI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=usqjamcTbtVaGCkh7xAY9zUqVLP/N2tr9W5rA87h10st1NRtdYMJtISxZyBR+RnPX JyRxscflboYuiwfybFJ5Byt/5kgl6O9aHmCx1Knpcm4FuUCEAdS28Vdn9KmDE9ecbm 3o8pIkt7Me/wQFRxcDTMzDPBXbSXG62uY9QCbt8kY/5K5v/4/TNmaC91zZ6mG1Cl0F sVw2D6p2SH3XhZQCjhOV/0GCs1yprYwa4iaVAFxa2eXvBzlqGIR4gyIMnUk8TM0Apj fx6G8E4KtgrE413xj3nwmQ/EI8leK0e1T9p1mpnkI006ykLoVPWlNgFg4xikRuId0Z tE57ViYlzD1Mg== Date: Mon, 28 Jun 2021 22:43:37 +0900 From: Masami Hiramatsu To: Peter Zijlstra Cc: jpoimboe@redhat.com, jbaron@akamai.com, rostedt@goodmis.org, ardb@kernel.org, naveen.n.rao@linux.ibm.com, anil.s.keshavamurthy@intel.com, davem@davemloft.net, linux-kernel@vger.kernel.org, kernel test robot Subject: Re: [PATCH 1/3] jump_label: Fix jump_label_text_reserved() vs __init Message-Id: <20210628224337.5429a2a898ea6f5e0d96d77c@kernel.org> In-Reply-To: <20210628113045.045141693@infradead.org> References: <20210628112409.233121975@infradead.org> <20210628113045.045141693@infradead.org> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; 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 Mon, 28 Jun 2021 13:24:10 +0200 Peter Zijlstra wrote: > It turns out that jump_label_text_reserved() was reporting __init text > as being reserved past the time when the __init text was freed and > re-used. > > For a long time, this resulted in, at worst, not being able to kprobe > text that happened to land at the re-used address. However a recent > commit e7bf1ba97afd ("jump_label, x86: Emit short JMP") made it a > fatal mistake because it now needs to read the instruction in order to > determine the conflict -- an instruction that's no longer there. > > Fixes: 4c3ef6d79328 ("jump label: Add jump_label_text_reserved() to reserve jump points") > Reported-by: kernel test robot > Signed-off-by: Peter Zijlstra (Intel) Looks good to me. Reviewed-by: Masami Hiramatsu Thank you, > --- > kernel/jump_label.c | 13 ++++++++----- > 1 file changed, 8 insertions(+), 5 deletions(-) > > --- a/kernel/jump_label.c > +++ b/kernel/jump_label.c > @@ -316,14 +316,16 @@ static int addr_conflict(struct jump_ent > } > > static int __jump_label_text_reserved(struct jump_entry *iter_start, > - struct jump_entry *iter_stop, void *start, void *end) > + struct jump_entry *iter_stop, void *start, void *end, bool init) > { > struct jump_entry *iter; > > iter = iter_start; > while (iter < iter_stop) { > - if (addr_conflict(iter, start, end)) > - return 1; > + if (init || !jump_entry_is_init(iter)) { > + if (addr_conflict(iter, start, end)) > + return 1; > + } > iter++; > } > > @@ -561,7 +563,7 @@ static int __jump_label_mod_text_reserve > > ret = __jump_label_text_reserved(mod->jump_entries, > mod->jump_entries + mod->num_jump_entries, > - start, end); > + start, end, mod->state == MODULE_STATE_COMING); > > module_put(mod); > > @@ -786,8 +788,9 @@ early_initcall(jump_label_init_module); > */ > int jump_label_text_reserved(void *start, void *end) > { > + bool init = system_state < SYSTEM_RUNNING; > int ret = __jump_label_text_reserved(__start___jump_table, > - __stop___jump_table, start, end); > + __stop___jump_table, start, end, init); > > if (ret) > return ret; > > -- Masami Hiramatsu