Gentoo Archives: gentoo-user

From: tuxic@××××××.de
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] x86.c:(.text+0xb2): undefined reference to `l1tf_vmx_mitigation' with linux kernel 4.18.1
Date: Fri, 17 Aug 2018 06:33:37
Message-Id: 20180817063315.d27n3657x4qyzj5s@solfire
In Reply to: Re: [gentoo-user] x86.c:(.text+0xb2): undefined reference to `l1tf_vmx_mitigation' with linux kernel 4.18.1 by Alexander Kapshuk
1 On 08/17 09:06, Alexander Kapshuk wrote:
2 > On Fri, Aug 17, 2018 at 8:58 AM Alexander Kapshuk
3 > <alexander.kapshuk@×××××.com> wrote:
4 > >
5 > > On Fri, Aug 17, 2018 at 8:57 AM Alexander Kapshuk
6 > > <alexander.kapshuk@×××××.com> wrote:
7 > > >
8 > > > On Fri, Aug 17, 2018 at 8:10 AM <tuxic@××××××.de> wrote:
9 > > > >
10 > > > > On 08/17 02:53, Adam Carter wrote:
11 > > > > > On Fri, Aug 17, 2018 at 1:15 PM, <tuxic@××××××.de> wrote:
12 > > > > >
13 > > > > > > Hi,
14 > > > > > >
15 > > > > > > CPU bugs seem to be more and more common:
16 > > > > > > https://www.heise.de/security/meldung/Linux-Kernel-und-
17 > > > > > > Distributionen-schuetzen-vor-Prozessorluecke-Foreshadow-L1TF-4137264.html
18 > > > > > > https://www.heise.de/security/meldung/Spectre-NG-Foreshadow-
19 > > > > > > gefaehrdet-Intel-Prozessoren-4137209.html
20 > > > > > > (sorry, I only know of this german spoken references...)
21 > > > > > >
22 > > > > > > With Linux kernel 4.18.1 Linus has introduced a fix (aka workaround)
23 > > > > > > of the Foreshadow bug.
24 > > > > > >
25 > > > > >
26 > > > > > 4.18, 4.17, 4.14, 4.9, and 4.4 have all had the fixes applied.
27 > > > > >
28 > > > > > >
29 > > > > > > Unfortunately compiling that kernel (as downloaded from
30 > > > > > > https://mirrors.edge.kernel.org/pub/linux/kernel/v4.x/ )
31 > > > > > >
32 > > > > > > gives me this bug:
33 > > > > > >
34 > > > > >
35 > > > > > gentoo-sources with gcc 7.3 builds fine for me.
36 > > > > >
37 > > > > > Intel: grep . /sys/devices/system/cpu/vulnerabilities/*
38 > > > > > /sys/devices/system/cpu/vulnerabilities/l1tf:Mitigation: PTE Inversion
39 > > > > > /sys/devices/system/cpu/vulnerabilities/meltdown:Mitigation: PTI
40 > > > > > /sys/devices/system/cpu/vulnerabilities/spec_store_bypass:Mitigation:
41 > > > > > Speculative Store Bypass disabled via prctl and seccomp
42 > > > > > /sys/devices/system/cpu/vulnerabilities/spectre_v1:Mitigation: __user
43 > > > > > pointer sanitization
44 > > > > > /sys/devices/system/cpu/vulnerabilities/spectre_v2:Mitigation: Full generic
45 > > > > > retpoline, IBPB, IBRS_FW
46 > > > > >
47 > > > > > AMD: grep . /sys/devices/system/cpu/vulnerabilities/*
48 > > > > > /sys/devices/system/cpu/vulnerabilities/l1tf:Not affected
49 > > > > > /sys/devices/system/cpu/vulnerabilities/meltdown:Not affected
50 > > > > > /sys/devices/system/cpu/vulnerabilities/spec_store_bypass:Mitigation:
51 > > > > > Speculative Store Bypass disabled via prctl and seccomp
52 > > > > > /sys/devices/system/cpu/vulnerabilities/spectre_v1:Mitigation: __user
53 > > > > > pointer sanitization
54 > > > > > /sys/devices/system/cpu/vulnerabilities/spectre_v2:Mitigation: Full AMD
55 > > > > > retpoline, IBPB
56 > > > >
57 > > > > Hi,
58 > > > >
59 > > > > I am happy, that other sources do work for you Adam.
60 > > > >
61 > > > > Interesting would be, why the original sources does not compile for
62 > > > > me.
63 > > > > Any idea?
64 > > > >
65 > > > >
66 > > > >
67 > > >
68 > > > This problem has been reported upstream. See below.
69 > > > https://lkml.org/lkml/2018/8/15/118
70 > > >
71 > > > In particular:
72 > > >
73 > > > Build is successful with
74 > > > CONFIG_KVM=y
75 > > > CONFIG_KVM_INTEL=y
76 > > > CONFIG_KVM_AMD=y
77 > > > but fails if only
78 > > > CONFIG_KVM=y
79 > > > CONFIG_KVM_AMD=y
80 > > > are selected.
81 > >
82 > > And a follow up email with a reference to a patch that addresses the issue:
83 > > https://lkml.org/lkml/2018/8/15/122
84 >
85 > The patch in question will become available in 4.18.2 upstream. See
86 > the link below.
87 > https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git/commit/?h=linux-4.18.y&id=eca268a3133cafcd188d85489f08a7c5907d985d
88 >
89
90
91 Hi Alexander,
92
93 THAT's helpful! Yeah! Thanks a lot!
94
95 The only question for me remains: Why does www.startpage.com (search
96 engine) couldn' find that (I tried that before....) ?
97
98 Cheers!
99 Meino
100
101 PS: The recompiling-engine has already powered up and restarted...all
102 motors are working heavily... :::)))