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=-12.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 2CB81C04AB5 for ; Mon, 3 Jun 2019 13:00:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 05D40279DA for ; Mon, 3 Jun 2019 13:00:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b="YcLh+vQP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727814AbfFCNAF (ORCPT ); Mon, 3 Jun 2019 09:00:05 -0400 Received: from terminus.zytor.com ([198.137.202.136]:35331 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726336AbfFCNAD (ORCPT ); Mon, 3 Jun 2019 09:00:03 -0400 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id x53CxlDD601575 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Mon, 3 Jun 2019 05:59:47 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 terminus.zytor.com x53CxlDD601575 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2019051801; t=1559566788; bh=sR4mY6kMBnO2Amto5Pvlrw0vCfovaVTLDM/RnUHkBu4=; h=Date:From:Cc:Reply-To:In-Reply-To:References:To:Subject:From; b=YcLh+vQPYmGYcB8uGb/DBuxS9zfI7s4dddISAYOkEg410+7PdiKcekX73qUq1Mn92 9C/TPrRSMN0VAwW+8J9NsBULEjiSaOMMtjHFUATzc/M1lYT6FxROB7vDw1P+B3Q92u /i3FeBXF1k+FGiSS7sfIqx47uA5btmrNKO0mO1vkjYPrXWcnd8bJnbSrdBDiltb373 8XZ35b1ctXxMNUxKxFm193SL0PhqNhYLBLqqoninCJpVGFj7CRKaK09IWJxNQS2kXH br2v7R4p0uXNpmTZ28pTgH84kJogkiEIUJ7i1QAn2LOuLgdOQ69w87mKVI7y9ceX78 9NesV4RItoUPQ== Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id x53Cxkjo601572; Mon, 3 Jun 2019 05:59:46 -0700 Date: Mon, 3 Jun 2019 05:59:46 -0700 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Rick Edgecombe Message-ID: Cc: mingo@kernel.org, linux-kernel@vger.kernel.org, mroos@linux.ee, dave.hansen@intel.com, luto@kernel.org, bp@alien8.de, rick.p.edgecombe@intel.com, akpm@linux-foundation.org, torvalds@linux-foundation.org, hpa@zytor.com, davem@davemloft.net, peterz@infradead.org, namit@vmware.com, tglx@linutronix.de Reply-To: mroos@linux.ee, linux-kernel@vger.kernel.org, mingo@kernel.org, luto@kernel.org, dave.hansen@intel.com, torvalds@linux-foundation.org, rick.p.edgecombe@intel.com, akpm@linux-foundation.org, bp@alien8.de, tglx@linutronix.de, namit@vmware.com, peterz@infradead.org, hpa@zytor.com, davem@davemloft.net In-Reply-To: <20190527211058.2729-3-rick.p.edgecombe@intel.com> References: <20190527211058.2729-3-rick.p.edgecombe@intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] mm/vmalloc: Avoid rare case of flushing TLB with weird arguments Git-Commit-ID: 31e67340cc65edfd9dac5ef26f81de8414ce5906 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 31e67340cc65edfd9dac5ef26f81de8414ce5906 Gitweb: https://git.kernel.org/tip/31e67340cc65edfd9dac5ef26f81de8414ce5906 Author: Rick Edgecombe AuthorDate: Mon, 27 May 2019 14:10:58 -0700 Committer: Ingo Molnar CommitDate: Mon, 3 Jun 2019 11:47:25 +0200 mm/vmalloc: Avoid rare case of flushing TLB with weird arguments In a rare case, flush_tlb_kernel_range() could be called with a start higher than the end. In vm_remove_mappings(), in case page_address() returns 0 for all pages (for example they were all in highmem), _vm_unmap_aliases() will be called with start = ULONG_MAX, end = 0 and flush = 1. If at the same time, the vmalloc purge operation is triggered by something else while the current operation is between remove_vm_area() and _vm_unmap_aliases(), then the vm mapping just removed will be already purged. In this case the call of vm_unmap_aliases() may not find any other mappings to flush and so end up flushing start = ULONG_MAX, end = 0. So only set flush = true if we find something in the direct mapping that we need to flush, and this way this can't happen. Signed-off-by: Rick Edgecombe Signed-off-by: Peter Zijlstra (Intel) Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: David S. Miller Cc: Linus Torvalds Cc: Meelis Roos Cc: Nadav Amit Cc: Peter Zijlstra Cc: Andrew Morton Cc: Thomas Gleixner Fixes: 868b104d7379 ("mm/vmalloc: Add flag for freeing of special permsissions") Link: https://lkml.kernel.org/r/20190527211058.2729-3-rick.p.edgecombe@intel.com Signed-off-by: Ingo Molnar --- mm/vmalloc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 93b2dca2aadb..4c9e150e5ad3 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -2125,6 +2125,7 @@ static void vm_remove_mappings(struct vm_struct *area, int deallocate_pages) { unsigned long start = ULONG_MAX, end = 0; int flush_reset = area->flags & VM_FLUSH_RESET_PERMS; + int flush_dmap = 0; int i; /* @@ -2163,6 +2164,7 @@ static void vm_remove_mappings(struct vm_struct *area, int deallocate_pages) if (addr) { start = min(addr, start); end = max(addr + PAGE_SIZE, end); + flush_dmap = 1; } } @@ -2172,7 +2174,7 @@ static void vm_remove_mappings(struct vm_struct *area, int deallocate_pages) * reset the direct map permissions to the default. */ set_area_direct_map(area, set_direct_map_invalid_noflush); - _vm_unmap_aliases(start, end, 1); + _vm_unmap_aliases(start, end, flush_dmap); set_area_direct_map(area, set_direct_map_default_noflush); }