From patchwork Tue Jan 31 20:05:43 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Al Viro X-Patchwork-Id: 13123367 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 64D90C636CC for ; Tue, 31 Jan 2023 20:05:57 +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:In-Reply-To:MIME-Version:References: Message-ID: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=Anzrbxi+k6QfgrdhT4LUp57o/6gMeugJUoAR5dZCYm4=; b=u4ZWTGGFYtuRza mUAisO74utTXk48THVjRokptTbWK2pFiwRGNTopgwj7wE4sAYf73y77q7LShbyjhb431c1WUMdeC/ 3OScaAvqJXGmbGEK/Jlih7435YCazv+hM1eJEgtEVv1fPY4le+rTIVOcVKaRQ3nxVWZTCgWAEaMCU iylT6bEW8kPPkoMBDNLIjaMRd4XNVLiLDtXEtzyKDYL4PZ8aaFO3tMh8X2xMburAs9CfRZnR5CBdn tjQRMdZjDUl2ZZvMlN8Oh6J2xy60uUsJQ2IHKTxUHvtkbgk6itfZONCBZHf7EVUjnfPYTao/Id0TB i8ad85qgRnmc8VGkl9UA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pMwt3-009DQD-VE; Tue, 31 Jan 2023 20:05:49 +0000 Received: from zeniv.linux.org.uk ([2a03:a000:7:0:5054:ff:fe1c:15ff]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1pMwt0-009DOP-Ft for linux-riscv@lists.infradead.org; Tue, 31 Jan 2023 20:05:47 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linux.org.uk; s=zeniv-20220401; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=wVcE+3BmnOfE/NwR5UjnA+ry4zfP0RI8olAVTcvgEUs=; b=Ct+tFykDR6lyUvgdiXaL+wDIv/ VFKiuRPBE9+1rOFXjTFIBjHI/P55UQYeegg4ROhJbh7VJrHAYz6EFq6N+X9LGTZvO8s+OvI5T7m9d qmQqtM6XOtNklHUYyAfzY0h/wRwNGPbnRNpVSNAxSoBo9MMFwyj6zvWApQgTlg7wfaK0w40U8kAwL tZaSXHiZmLA8SHXOzUDL9f2Pp+sChQqZRPkIOLXDx2QoHern1VKKeXIUcTcuvVj0N/fhBl775dcOT GOTmusZ8rUu+c3bWVqkzxdmhQULmaNnZH4EqUIU+DRw/mxAc8nmXIKaaBdqT5RIwNXWNYPVPOMzgN LnAE7PlQ==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.96 #2 (Red Hat Linux)) id 1pMwsx-005InU-0T; Tue, 31 Jan 2023 20:05:43 +0000 Date: Tue, 31 Jan 2023 20:05:43 +0000 From: Al Viro To: linux-arch@vger.kernel.org Cc: linux-alpha@vger.kernel.org, linux-ia64@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-m68k@lists.linux-m68k.org, Michal Simek , Dinh Nguyen , openrisc@lists.librecores.org, linux-parisc@vger.kernel.org, linux-riscv@lists.infradead.org, sparclinux@vger.kernel.org, Linus Torvalds Subject: [PATCH 06/10] nios2: fix livelock in uaccess Message-ID: References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230131_120546_543339_1DF06E5D X-CRM114-Status: GOOD ( 13.58 ) 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: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org nios2 equivalent of 26178ec11ef3 "x86: mm: consolidate VM_FAULT_RETRY handling" If e.g. get_user() triggers a page fault and a fatal signal is caught, we might end up with handle_mm_fault() returning VM_FAULT_RETRY and not doing anything to page tables. In such case we must *not* return to the faulting insn - that would repeat the entire thing without making any progress; what we need instead is to treat that as failed (user) memory access. Signed-off-by: Al Viro --- arch/nios2/mm/fault.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/nios2/mm/fault.c b/arch/nios2/mm/fault.c index edaca0a6c1c1..ca64eccea551 100644 --- a/arch/nios2/mm/fault.c +++ b/arch/nios2/mm/fault.c @@ -136,8 +136,11 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long cause, */ fault = handle_mm_fault(vma, address, flags, regs); - if (fault_signal_pending(fault, regs)) + if (fault_signal_pending(fault, regs)) { + if (!user_mode(regs)) + goto no_context; return; + } /* The fault is fully completed (including releasing mmap lock) */ if (fault & VM_FAULT_COMPLETED)