From patchwork Tue Jan 31 20:06:48 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Al Viro X-Patchwork-Id: 13123370 X-Patchwork-Delegate: palmer@dabbelt.com 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 D93BAC38142 for ; Tue, 31 Jan 2023 20:07:00 +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=bNKbn9DDyn8wPRmdaRtAGV/aCLU7Qugbn8mr4tnG8Nc=; b=d/dl1HcWEUa3Zr SMxvtnvNs3UHytzmjP+BJdJq4rcRuync1JKhicV6mYpPKz8e8UdfwjkpK2BaWs9aFr9Ws54zLk5zo lGvtI8y3UsWel7dKZZt7yyY3rsZ7is7myuuKjHJLiFQaozfS2KZDHboScr/9iVCnPPLfFzd2svhyM As95Pl14s78H7d5E5wbGpoCuhALDc1UmR0lgbStMF8y15i1a19++ssWlB4SMlLe+inTU6CM0rcbEJ NItFqs01fUAQfKLj4mPg9boQvePBjVo5O14xJ5z80aZJJLjB8X/KNn1SrJ1xB+o6bAc9WaWsuEC8Z Vz5WRqboIErbwsYGNpRw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pMwu6-009Dou-3n; Tue, 31 Jan 2023 20:06:54 +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 1pMwu3-009DnZ-RW for linux-riscv@lists.infradead.org; Tue, 31 Jan 2023 20:06:53 +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=nvc6EOOE6Kc37iQ5tEQ7l2xOJqqEJfVCbXPLSTxaEF4=; b=wdY4q/NUsSzoOzzSH9JWxFXi7s Tk1MepTXqcFNQuqsv6PLGLDlWg/ho5Hq7LbS/6/Ozd57SshWTeDBArvFWXDhGFh2BhNX8dBI4LgkO LpJmKqpkO4x5vY1+b9CcqUE0aGIpoyS5qStg8iBjcK+HypQyzzYiPNvF/dOM89WyZgG3dUo1oR8AB ONYs1wDgkd19QVLeBTvry12xY2pe789ERsnyEmEuQrns462tlSiqhjy4E15CVoyugsuWlzfNMig0b a6a88eJ+8ZtJ/kyRgEu6wVtRz1ghz6pXOq3cyUYQcf7ksmGIi6rbK4dPwUT0N6fTylQGUN8noABNX qOw7Ui/A==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.96 #2 (Red Hat Linux)) id 1pMwu0-005IoI-1G; Tue, 31 Jan 2023 20:06:48 +0000 Date: Tue, 31 Jan 2023 20:06:48 +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 09/10] riscv: 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_120651_903376_27C8E9B6 X-CRM114-Status: GOOD ( 13.79 ) 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 riscv 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 Tested-by: Björn Töpel Tested-by: Geert Uytterhoeven --- arch/riscv/mm/fault.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c index d86f7cebd4a7..c91d85349d39 100644 --- a/arch/riscv/mm/fault.c +++ b/arch/riscv/mm/fault.c @@ -324,8 +324,11 @@ asmlinkage void do_page_fault(struct pt_regs *regs) * signal first. We do not need to release the mmap_lock because it * would already be released in __lock_page_or_retry in mm/filemap.c. */ - if (fault_signal_pending(fault, regs)) + if (fault_signal_pending(fault, regs)) { + if (!user_mode(regs)) + no_context(regs, addr); return; + } /* The fault is fully completed (including releasing mmap lock) */ if (fault & VM_FAULT_COMPLETED)