From: Alexey Dobriyan <adobriyan@gmail.com>
To: pbonzini@redhat.com, rkrcmar@redhat.com, tglx@linutronix.de,
mingo@redhat.com, hpa@zytor.com, dave.hansen@linux.intel.com
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
x86@kernel.org, dwmw@amazon.co.uk, arjan@linux.intel.com
Subject: Re: tip/master falls off NOP cliff with KPTI under KVM
Date: Thu, 11 Jan 2018 01:34:57 +0300 [thread overview]
Message-ID: <20180110223457.GA1762@avx2> (raw)
In-Reply-To: <20180110220814.GA29262@avx2>
On Thu, Jan 11, 2018 at 01:08:14AM +0300, Alexey Dobriyan wrote:
> Sorry, if everyone posted this kvm boot fail.
> Adding "nopti" makes everything boot.
>
> tip/master
>
> commit 392b9cd85deec6e7f3e0fd97aac9aef2006c640b (HEAD, tip/master, tip/auto-latest)
> Merge: 6b34948099b2 07881166a892
>
> Merge branch 'sched/core'
>
> debian 8.8 image
>
> KVM:
>
> qemu-system-x86_64 -smp cpus=2 -m 1024 ... -append 'root=/dev/sda1 ignore_loglevel console=ttyAMA0 console=ttyS0'
>
> [ 0.982804] Freeing unused kernel memory: 952K
> [ 0.990333] x86/mm: Checked W+X mappings: passed, no W+X pages found.
> [ 0.990980] x86/mm: Checking user space page tables
> [ 0.998409] x86/mm: Checked W+X mappings: passed, no W+X pages found.
> [ 1.003149] kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
> [ 1.003815] BUG: unable to handle kernel paging request at fffffe0000007000
> [ 1.004424] IP: 0xfffffe0000007000
> [ 1.004727] PGD 3ffd8067 P4D 3ffd8067 PUD 3ffd7067 PMD 3fe15067 PTE 800000003fc09063
> [ 1.005402] Oops: 0011 [#1] PREEMPT SMP PTI
> [ 1.005775] CPU: 0 PID: 1 Comm: init Not tainted 4.15.0-rc7-00482-g392b9cd85dee #5
> [ 1.006432] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1.fc27 04/01/2014
> [ 1.007239] RIP: 0010:0xfffffe0000007000
> [ 1.007589] RSP: 0018:ffffc9000000bfd0 EFLAGS: 00010006
> [ 1.008046] RAX: 000000000000000c RBX: 000055781b7fa040 RCX: 00007f78208d00bc
> [ 1.008815] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff81400000
> [ 1.009636] RBP: 000000000000000a R08: 000000000000037f R09: 0000000000000064
> [ 1.010509] R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffbc3eef99
> [ 1.011225] R13: 0000000000000000 R14: 000055781b81cc03 R15: 0000000000001000
> [ 1.011938] FS: 0000000000000000(0000) GS:ffff88003fc00000(0000) knlGS:0000000000000000
> [ 1.012723] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 1.013285] CR2: fffffe0000007000 CR3: 000000003da04000 CR4: 00000000000006b0
> [ 1.013960] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 1.014636] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [ 1.015339] Call Trace:
> [ 1.015595] Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <00> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> [ 1.017500] RIP: 0xfffffe0000007000 RSP: ffffc9000000bfd0
> [ 1.018037] CR2: fffffe0000007000
Bisection points to
f3433c1010c6af61c9897f0f0447f81b991feac1 is the first bad commit
commit f3433c1010c6af61c9897f0f0447f81b991feac1
Author: David Woodhouse <dwmw@amazon.co.uk>
Date: Tue Jan 9 14:43:11 2018 +0000
x86/retpoline/entry: Convert entry assembler indirect jumps
RETPOLINE is enabled but build system is reporting that compiler doesn't
support it (Gentoo 6.4.0 p1.1)
Disabling CONFIG_RETPOLINE fixes boot.
And build system reports that "system may be insecure" even if RETPOLINE
is disabled.
next prev parent reply other threads:[~2018-01-10 22:35 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-10 22:08 tip/master falls off NOP cliff with KPTI under KVM Alexey Dobriyan
2018-01-10 22:34 ` Alexey Dobriyan [this message]
2018-01-10 22:53 ` Woodhouse, David
2018-01-25 0:53 ` Dexuan-Linux Cui
2018-01-25 7:53 ` David Woodhouse
2018-01-25 19:00 ` Dexuan Cui
2018-01-25 19:13 ` Thomas Gleixner
2018-01-25 19:35 ` Dexuan-Linux Cui
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