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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 96457C43381 for ; Tue, 2 Apr 2019 08:03:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6246420856 for ; Tue, 2 Apr 2019 08:03:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554192220; bh=lXG61drHYKWkH6JkBOWzJQigVdmu7d5++K4qQ0nR6fY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=IVCz75lrXjPmgFo3sfjNilb1zRoSWEvKq6NwWkB3b22gOwgCvWlx4BXBMdO8ITbgb Lpfy9GIO9IwBGQ3ECh3zEhwbOhDyUvI9Qjmhc+4qCUibqfvDxdEJJT/VA9ZmzPoUtO asCJ3oGgcmv9LXrGeVxO6+GdLZ3GoXMiuhECyKWM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729040AbfDBIDj (ORCPT ); Tue, 2 Apr 2019 04:03:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:41462 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725778AbfDBIDj (ORCPT ); Tue, 2 Apr 2019 04:03:39 -0400 Received: from localhost.localdomain (unknown [115.192.191.234]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 167F620830; Tue, 2 Apr 2019 08:03:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554192218; bh=lXG61drHYKWkH6JkBOWzJQigVdmu7d5++K4qQ0nR6fY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fVLzstJbIsNs/lJESTdus9nNjlp+OfV5VYENhKjX4AVWbE9YpNfZuZxVu3dN/1AO6 jOsUpiWtHRiwfFMOALwW0wSIYn/aDIDtluGkd/cINLiHJlDDsAsnhSWZLuzEGQq5P4 7mcPBIx97phlkSwKEKndqCtQfUfOrh6qkVCq2P2c= From: guoren@kernel.org To: arnd@arndb.de, palmer@sifive.com Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, ren_guo@c-sky.com, linux-riscv@lists.infradead.org Subject: [PATCH 3/3] riscv/signal: Fixup additional syscall restarting Date: Tue, 2 Apr 2019 16:02:33 +0800 Message-Id: <1554192153-2587-3-git-send-email-guoren@kernel.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1554192153-2587-1-git-send-email-guoren@kernel.org> References: <1554192153-2587-1-git-send-email-guoren@kernel.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Guo Ren The function of do_notify_resume called by entry.S could be entered in loop when SIGPENDING was setted again before sret. So we must add prevent code to make syscall restart (regs->sepc -= 0x4) or it may re-execute unexpected instructions. Just like in_syscall & forget_syscall used by arm. Signed-off-by: Guo Ren Cc: Palmer Dabbelt Cc: Arnd Bergmann --- arch/riscv/kernel/signal.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c index 837e164..804d6ee 100644 --- a/arch/riscv/kernel/signal.c +++ b/arch/riscv/kernel/signal.c @@ -234,6 +234,9 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) /* Are we from a system call? */ if (regs->scause == EXC_SYSCALL) { + /* Avoid additional syscall restarting via ret_from_exception */ + regs->scause = -1UL; + /* If so, check system call restarting.. */ switch (regs->a0) { case -ERESTART_RESTARTBLOCK: @@ -272,6 +275,9 @@ static void do_signal(struct pt_regs *regs) /* Did we come from a system call? */ if (regs->scause == EXC_SYSCALL) { + /* Avoid additional syscall restarting via ret_from_exception */ + regs->scause = -1UL; + /* Restart the system call - no handlers present */ switch (regs->a0) { case -ERESTARTNOHAND: -- 2.7.4