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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 475A3C44507 for ; Wed, 15 Jul 2026 01:37:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:Message-ID: In-Reply-To:Subject:cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=YTer2qphVkN8X3eIFRz497gY+YcxnZLuXynmI3U28bY=; b=MoQD4GtyPkFBI7 NYsDsCVK86E5OgdFxlct1hRyTjG12IsRwrqYEpXohiJF3K0KKh7B5VUYLGH/QviPnwvlLVPz9ISxQ NgcSl6iZt0yeqG5ylzPHCMxmrlF5HEks4KzwT/zia1xrBo7PJHgaLHMprk+V6V4qsuTxNroKJZCrz zwQ5tGdleqo079FQv7g1VxrBZhX7iO7W4MAuZkdP4KUnVRhO4Ae4d4M6/J0iNcWp6lUYFt6QTTanK qaB1oCvY9LNm6zrTs5iXVQ0jhenfHCqjB86T2FWxXNaKFbIanjihyUIkkl/d7wExCDcmEsbnIeHdZ G6whCNTkeImeCocMTpLQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wjoYe-0000000DZlW-33m6; Wed, 15 Jul 2026 01:37:08 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wjoYc-0000000DZlN-2Ou8 for linux-riscv@lists.infradead.org; Wed, 15 Jul 2026 01:37:06 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 5A20D600BB; Wed, 15 Jul 2026 01:37:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 60DBE1F000E9; Wed, 15 Jul 2026 01:37:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784079425; bh=9hXZES7boB1AazsyWISWT/pKV6aI6aU3YaJu2A6dM9A=; h=Date:From:To:cc:Subject:In-Reply-To:References; b=ovoxpEfAm6BRlTFAj8F0Dcxc0hGE0wO2LKOumO8vahRNCvUgxSr+blYzcInG0T2Me A+CfHvczZTGL4+VdLFmP3oBOLW+0afzsaybGZucSLiezkYR5VuHXAtsMJML2AFKNG2 ri5a/uSwIPKpBJJDVMN3YUoIV0gqYzf9wIUZp3Jh+VYvpTsvF76oJFjueh/N7BtHdH 0HUbLKCkrzBQ4iM4QMinMIcVaeJUx/THVhrDiDyF448pJabUv4xEvUqeFGt9MMty7Y zEI4CIxQrKdQd1UuclmleDvwV0bzV7+wZSly5tFnKlVRrxxYnm+y93HdIWYT8qVAgq bkgCDLYuWelJw== Date: Tue, 14 Jul 2026 19:37:01 -0600 (MDT) From: Paul Walmsley To: Aurelien Jarno cc: Paul Walmsley , Joel Stanley , linux-kernel@vger.kernel.org, Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Jim Shu , Zong Li , Deepak Gupta , "open list:RISC-V ARCHITECTURE" Subject: Re: [PATCH] arch/riscv: vdso: remove CFI landing pad from rt_sigreturn In-Reply-To: Message-ID: References: <20260623204058.498120-1-aurelien@aurel32.net> MIME-Version: 1.0 X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org Hi Aurelien, Joel, On Tue, 14 Jul 2026, Aurelien Jarno wrote: > On 2026-06-29 17:08, Joel Stanley wrote: > > On Fri, 26 Jun 2026 at 03:33, Paul Walmsley wrote: > > > On Tue, 23 Jun 2026, Aurelien Jarno wrote: > > > > > > > When CONFIG_RISCV_USER_CFI is enabled, the CFI version of the vDSO, has > > > > a CFI landing pad instruction at the start of __vdso_rt_sigreturn. This > > > > breaks libgcc's unwinding code which matches on the first two > > > > instructions. Other unwinders that rely on similar instruction matching > > > > may also be affected. > > > > > > > > Since __vdso_rt_sigreturn is reached as part of signal-return handling > > > > rather than via an indirect call/jump from userspace, it does not need a > > > > CFI landing pad. Remove it and restore the instruction sequence expected > > > > by existing unwinding code. > > > > > > > > This matches what was done on arm64 in commit 9a964285572b ("arm64: > > > > vdso: Don't prefix sigreturn trampoline with a BTI C instruction") for a > > > > similar issue. > > > > > > > > Fixes: 37f57bd3faea ("arch/riscv: compile vdso with landing pad and shadow stack note") > > > > Co-authored-by: Joel Stanley > > > > Signed-off-by: Aurelien Jarno > > > > > > I'd like to take this one. But since you're listed as the co-author, I > > > probably need your Signed-off-by: as well. Care to reply with it? > > > > Signed-off-by: Joel Stanley > > > > Thanks Aurelien for working with me on this one. I saw CFI was > > disabled in the debian kernel config and wondered why (failing glibc > > backtrace tests with CFI enabled), and we got to the bottom of it. > > > > This one should go to stable IMO. > > Now that Joel answered with a Signed-off-by, would it be possible to get > this merged for 7.2? Of course; thank you for the reminder. Thanks for the patch and the S-o-b, queued for v7.2-rc with a cc: to stable@vger. - Paul _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv