From patchwork Tue Jan 31 20:07:17 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Al Viro X-Patchwork-Id: 13123371 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 D48F9C38142 for ; Tue, 31 Jan 2023 20:07:30 +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=VfJ8j/NpqbQ0m3FNESr2oSVlhZ4YV0q37GGMDivrmWY=; b=VhpBLDGjV/AvrT vwIHWU4LdV8J4qlapcw0x1j1SJYeAwXkyJyujOOoP9Ir+L+jKSytJ77PBh4v/E75AEByHC+s5SXd0 MyN9CNdFc6936ihHj9JlLJllnD+hCy6xX0VI5jzf1kWaOF7FybWTz9dtl87hE0C7W2OY94kGo0gPR yA/rY/y4CbOIlbqVNtASX+vgAEHjoIhZOVKnL1J9DfZvyRqz3VyZry5+amMmnfMztms/UyMlsiroQ 3LYr6O+6aubcebWRxAo4UgToSwPBWMrqTr/uMQp/o/EbvpG0fSqOlSWecMRQENoxclINg0vF5BXsN lNkVhCsUqYkrE6rpoUGg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pMwua-009DzA-8c; Tue, 31 Jan 2023 20:07:24 +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 1pMwuY-009DyK-A7 for linux-riscv@lists.infradead.org; Tue, 31 Jan 2023 20:07:23 +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=fkGQb+Z+Q8nqxAsgBkwiDlyCIx3ldW4LiysiQRChEQY=; b=uiRdXlLmPVjFhiEbdNWx2iBg/L ukT6759SKWvD4VTcf7s8Zrnsy20tZQIyfGpDAYQMZK4Vr2bXIoZfz9SOM1xMKM3izRzmQrCiw1f59 7UEFhjpIZP09LO6b7yhwL8PNq1KyjxUHtjTU7yoIPqR36F37H94mx0pWJ3RipDcr8xYjM1AAKeQ3J xKdN74J8AHWk6MLBfur4EYMpaBLeXd7YgHATaE32CWS+oS9CqUV91B1jzUXKjV+MrSoHKbtmYhCoh 8etJOX4tJer3i70iBmbcFo15uIh3SC5WE7al3VG5ojYolEtBMrtuCEO4yPEAB5yxFlJ8pp4muojCB NT+qnH5Q==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.96 #2 (Red Hat Linux)) id 1pMwuT-005Ioa-1X; Tue, 31 Jan 2023 20:07:17 +0000 Date: Tue, 31 Jan 2023 20:07:17 +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 10/10] sparc: 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_120722_364676_600C0D05 X-CRM114-Status: GOOD ( 13.61 ) 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 sparc 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/sparc/mm/fault_32.c | 5 ++++- arch/sparc/mm/fault_64.c | 7 ++++++- 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/arch/sparc/mm/fault_32.c b/arch/sparc/mm/fault_32.c index 91259f291c54..179295b14664 100644 --- a/arch/sparc/mm/fault_32.c +++ b/arch/sparc/mm/fault_32.c @@ -187,8 +187,11 @@ asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write, */ fault = handle_mm_fault(vma, address, flags, regs); - if (fault_signal_pending(fault, regs)) + if (fault_signal_pending(fault, regs)) { + if (!from_user) + goto no_context; return; + } /* The fault is fully completed (including releasing mmap lock) */ if (fault & VM_FAULT_COMPLETED) diff --git a/arch/sparc/mm/fault_64.c b/arch/sparc/mm/fault_64.c index 4acc12eafbf5..d91305de694c 100644 --- a/arch/sparc/mm/fault_64.c +++ b/arch/sparc/mm/fault_64.c @@ -424,8 +424,13 @@ asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs) fault = handle_mm_fault(vma, address, flags, regs); - if (fault_signal_pending(fault, regs)) + if (fault_signal_pending(fault, regs)) { + if (regs->tstate & TSTATE_PRIV) { + insn = get_fault_insn(regs, insn); + goto handle_kernel_fault; + } goto exit_exception; + } /* The fault is fully completed (including releasing mmap lock) */ if (fault & VM_FAULT_COMPLETED)