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=-8.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 CAF96C33C9B for ; Tue, 7 Jan 2020 04:04:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9888A2080A for ; Tue, 7 Jan 2020 04:04:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ea3+4Fiz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727452AbgAGEEd (ORCPT ); Mon, 6 Jan 2020 23:04:33 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:45960 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727492AbgAGEEb (ORCPT ); Mon, 6 Jan 2020 23:04:31 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1578369868; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=QW0p8oTlxhvKg2yrL/7zWX0v0cvnMqmEy8AF/MJVcXM=; b=ea3+4FizWhYvcXUKb5gWQcDZbh8kFWW2I+ehxHQJu67lyZmFUSAOro0vSPqjcpAiFOy2lO QvXSVThu10/+3ZebBR4fy7w5RgcpC/E2mJHRuM9aw/WOhFvtePMFitQb3vQJg1sCMq4pvn Q7KzysKzNliiCw1n0Zo9bklalB4sZpA= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-427-j9l31aZrPj-tj4ronKLGRA-1; Mon, 06 Jan 2020 23:04:25 -0500 X-MC-Unique: j9l31aZrPj-tj4ronKLGRA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B037B1005513; Tue, 7 Jan 2020 04:04:23 +0000 (UTC) Received: from dhcp-128-65.nay.redhat.com (ovpn-12-32.pek2.redhat.com [10.72.12.32]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5D90F5C21A; Tue, 7 Jan 2020 04:04:19 +0000 (UTC) Date: Tue, 7 Jan 2020 12:04:15 +0800 From: Dave Young To: Dan Williams Cc: mingo@redhat.com, Taku Izumi , Michael Weiser , Ard Biesheuvel , Thomas Gleixner , Ingo Molnar , linux-efi@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org Subject: Re: [PATCH v4 4/4] efi: Fix handling of multiple efi_fake_mem= entries Message-ID: <20200107040415.GA19309@dhcp-128-65.nay.redhat.com> References: <157835762222.1456824.290100196815539830.stgit@dwillia2-desk3.amr.corp.intel.com> <157835764298.1456824.224151767362114611.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <157835764298.1456824.224151767362114611.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org On 01/06/20 at 04:40pm, Dan Williams wrote: > Dave noticed that when specifying multiple efi_fake_mem= entries only > the last entry was successfully being reflected in the efi memory map. > This is due to the fact that the efi_memmap_insert() is being called > multiple times, but on successive invocations the insertion should be > applied to the last new memmap rather than the original map at > efi_fake_memmap() entry. > > Rework efi_fake_memmap() to install the new memory map after each > efi_fake_mem= entry is parsed. > > This also fixes an issue in efi_fake_memmap() that caused it to litter > emtpy entries into the end of the efi memory map. An empty entry causes > efi_memmap_insert() to attempt more memmap splits / copies than > efi_memmap_split_count() accounted for when sizing the new map. When > that happens efi_memmap_insert() may overrun its allocation, and if you > are lucky will spill over to an unmapped page leading to crash > signature like the following rather than silent corruption: > > BUG: unable to handle page fault for address: ffffffffff281000 > [..] > RIP: 0010:efi_memmap_insert+0x11d/0x191 > [..] > Call Trace: > ? bgrt_init+0xbe/0xbe > ? efi_arch_mem_reserve+0x1cb/0x228 > ? acpi_parse_bgrt+0xa/0xd > ? acpi_table_parse+0x86/0xb8 > ? acpi_boot_init+0x494/0x4e3 > ? acpi_parse_x2apic+0x87/0x87 > ? setup_acpi_sci+0xa2/0xa2 > ? setup_arch+0x8db/0x9e1 > ? start_kernel+0x6a/0x547 > ? secondary_startup_64+0xb6/0xc0 > > Commit af1648984828 "x86/efi: Update e820 with reserved EFI boot > services data to fix kexec breakage" is listed in Fixes: since it > introduces more occurrences where efi_memmap_insert() is invoked after > an efi_fake_mem= configuration has been parsed. Previously the side > effects of vestigial empty entries were benign, but with commit > af1648984828 that follow-on efi_memmap_insert() invocation triggers > efi_memmap_insert() overruns. > > Fixes: 0f96a99dab36 ("efi: Add 'efi_fake_mem' boot option") > Fixes: af1648984828 ("x86/efi: Update e820 with reserved EFI boot services...") A nitpick for the Fixes flags, as I replied in the thread below: https://lore.kernel.org/linux-efi/CAPcyv4jLxqPaB22Ao9oV31Gm=b0+Phty+Uz33Snex4QchOUb0Q@mail.gmail.com/T/#m2bb2dd00f7715c9c19ccc48efef0fcd5fdb626e7 I reproduced two other panics without the patches applied, so this issue is not caused by either of the commits, maybe just drop the Fixes. > Link: https://lore.kernel.org/r/20191231014630.GA24942@dhcp-128-65.nay.redhat.com > Reported-by: Dave Young > Cc: Taku Izumi > Cc: Michael Weiser > Cc: Ard Biesheuvel > Cc: Thomas Gleixner > Cc: Ingo Molnar > Signed-off-by: Dan Williams > --- > drivers/firmware/efi/fake_mem.c | 31 ++++++++++++++++--------------- > drivers/firmware/efi/memmap.c | 2 +- > include/linux/efi.h | 2 ++ > 3 files changed, 19 insertions(+), 16 deletions(-) > > diff --git a/drivers/firmware/efi/fake_mem.c b/drivers/firmware/efi/fake_mem.c > index a8d20568d532..6e0f34a38171 100644 > --- a/drivers/firmware/efi/fake_mem.c > +++ b/drivers/firmware/efi/fake_mem.c > @@ -34,25 +34,16 @@ static int __init cmp_fake_mem(const void *x1, const void *x2) > return 0; > } > > -void __init efi_fake_memmap(void) > +static void __init efi_fake_range(struct efi_mem_range *efi_range) > { > struct efi_memory_map_data data = { 0 }; > int new_nr_map = efi.memmap.nr_map; > efi_memory_desc_t *md; > void *new_memmap; > - int i; > - > - if (!efi_enabled(EFI_MEMMAP) || !nr_fake_mem) > - return; > > /* count up the number of EFI memory descriptor */ > - for (i = 0; i < nr_fake_mem; i++) { > - for_each_efi_memory_desc(md) { > - struct range *r = &efi_fake_mems[i].range; > - > - new_nr_map += efi_memmap_split_count(md, r); > - } > - } > + for_each_efi_memory_desc(md) > + new_nr_map += efi_memmap_split_count(md, &efi_range->range); For this part, although I still have some concerns, but since I'm not 100% clear about it, maybe just leave it as you do, and see if it is good to Ard. > > /* allocate memory for new EFI memmap */ > if (efi_memmap_alloc(new_nr_map, &data) != 0) > @@ -61,17 +52,27 @@ void __init efi_fake_memmap(void) > /* create new EFI memmap */ > new_memmap = early_memremap(data.phys_map, data.size); > if (!new_memmap) { > - memblock_free(data.phys_map, data.size); > + __efi_memmap_free(data.phys_map, data.size, data.flags); > return; > } > > - for (i = 0; i < nr_fake_mem; i++) > - efi_memmap_insert(&efi.memmap, new_memmap, &efi_fake_mems[i]); > + efi_memmap_insert(&efi.memmap, new_memmap, efi_range); > > /* swap into new EFI memmap */ > early_memunmap(new_memmap, data.size); > > efi_memmap_install(&data); > +} > + > +void __init efi_fake_memmap(void) > +{ > + int i; > + > + if (!efi_enabled(EFI_MEMMAP) || !nr_fake_mem) > + return; > + > + for (i = 0; i < nr_fake_mem; i++) > + efi_fake_range(&efi_fake_mems[i]); > > /* print new EFI memmap */ > efi_print_memmap(); > diff --git a/drivers/firmware/efi/memmap.c b/drivers/firmware/efi/memmap.c > index bffa320d2f9a..1b6a4aa78a09 100644 > --- a/drivers/firmware/efi/memmap.c > +++ b/drivers/firmware/efi/memmap.c > @@ -29,7 +29,7 @@ static phys_addr_t __init __efi_memmap_alloc_late(unsigned long size) > return PFN_PHYS(page_to_pfn(p)); > } > > -static void __init __efi_memmap_free(u64 phys, unsigned long size, unsigned long flags) > +void __init __efi_memmap_free(u64 phys, unsigned long size, unsigned long flags) > { > if (flags & EFI_MEMMAP_MEMBLOCK) { > if (slab_is_available()) > diff --git a/include/linux/efi.h b/include/linux/efi.h > index 416eac01b1a1..539e81c942dc 100644 > --- a/include/linux/efi.h > +++ b/include/linux/efi.h > @@ -1062,6 +1062,8 @@ extern void __iomem *efi_lookup_mapped_addr(u64 phys_addr); > > extern int __init efi_memmap_alloc(unsigned int num_entries, > struct efi_memory_map_data *data); > +extern void __efi_memmap_free(u64 phys, unsigned long size, > + unsigned long flags); > extern int __init efi_memmap_init_early(struct efi_memory_map_data *data); > extern int __init efi_memmap_init_late(phys_addr_t addr, unsigned long size); > extern void __init efi_memmap_unmap(void); > Thanks Dave