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Sean Christopherson 669a8866e4 KVM: x86: Immediately reset the MMU context when the SMM flag is cleared commit `78fcb2c91a` upstream. Immediately reset the MMU context when the vCPU's SMM flag is cleared so that the SMM flag in the MMU role is always synchronized with the vCPU's flag. If RSM fails (which isn't correctly emulated), KVM will bail without calling post_leave_smm() and leave the MMU in a bad state. The bad MMU role can lead to a NULL pointer dereference when grabbing a shadow page's rmap for a page fault as the initial lookups for the gfn will happen with the vCPU's SMM flag (=0), whereas the rmap lookup will use the shadow page's SMM flag, which comes from the MMU (=1). SMM has an entirely different set of memslots, and so the initial lookup can find a memslot (SMM=0) and then explode on the rmap memslot lookup (SMM=1). general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 1 PID: 8410 Comm: syz-executor382 Not tainted 5.13.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__gfn_to_rmap arch/x86/kvm/mmu/mmu.c:935 [inline] RIP: 0010:gfn_to_rmap+0x2b0/0x4d0 arch/x86/kvm/mmu/mmu.c:947 Code: <42> 80 3c 20 00 74 08 4c 89 ff e8 f1 79 a9 00 4c 89 fb 4d 8b 37 44 RSP: 0018:ffffc90000ffef98 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff888015b9f414 RCX: ffff888019669c40 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001 RBP: 0000000000000001 R08: ffffffff811d9cdb R09: ffffed10065a6002 R10: ffffed10065a6002 R11: 0000000000000000 R12: dffffc0000000000 R13: 0000000000000003 R14: 0000000000000001 R15: 0000000000000000 FS: 000000000124b300(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000028e31000 CR4: 00000000001526e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rmap_add arch/x86/kvm/mmu/mmu.c:965 [inline] mmu_set_spte+0x862/0xe60 arch/x86/kvm/mmu/mmu.c:2604 __direct_map arch/x86/kvm/mmu/mmu.c:2862 [inline] direct_page_fault+0x1f74/0x2b70 arch/x86/kvm/mmu/mmu.c:3769 kvm_mmu_do_page_fault arch/x86/kvm/mmu.h:124 [inline] kvm_mmu_page_fault+0x199/0x1440 arch/x86/kvm/mmu/mmu.c:5065 vmx_handle_exit+0x26/0x160 arch/x86/kvm/vmx/vmx.c:6122 vcpu_enter_guest+0x3bdd/0x9630 arch/x86/kvm/x86.c:9428 vcpu_run+0x416/0xc20 arch/x86/kvm/x86.c:9494 kvm_arch_vcpu_ioctl_run+0x4e8/0xa40 arch/x86/kvm/x86.c:9722 kvm_vcpu_ioctl+0x70f/0xbb0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3460 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:1069 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:1055 do_syscall_64+0x3f/0xb0 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x440ce9 Cc: stable@vger.kernel.org Reported-by: syzbot+fb0b6a7e8713aeb0319c@syzkaller.appspotmail.com Fixes: `9ec19493fb` ("KVM: x86: clear SMM flags before loading state while leaving SMM") Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210609185619.992058-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		History 2021-06-23 14:42:51 +02:00
arch
block	blk-mq: Swap two calls in blk_mq_exit_queue()	2021-05-19 10:13:14 +02:00
certs	certs: Fix blacklist flag type confusion	2021-03-04 11:37:59 +01:00
crypto	async_xor: check src_offs is not NULL before updating it	2021-06-16 12:01:40 +02:00
Documentation	ASoC: meson: gx-card: fix sound-dai dt schema	2021-06-16 12:01:45 +02:00
drivers	PCI: Work around Huawei Intelligent NIC VF FLR erratum	2021-06-23 14:42:51 +02:00
fs	fanotify: fix copy_event_to_user() fid error clean up	2021-06-23 14:42:41 +02:00
include	mm: relocate 'write_protect_seq' in struct mm_struct	2021-06-23 14:42:49 +02:00
init	pid: take a reference when initializing `cad_pid`	2021-06-10 13:39:26 +02:00
ipc	ipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry	2021-05-26 12:06:54 +02:00
kernel	tracing: Do no increment trace_clock_global() by one	2021-06-23 14:42:50 +02:00
lib	lib/lz4: explicitly support in-place decompression	2021-06-10 13:39:29 +02:00
LICENSES	LICENSES/deprecated: add Zlib license text	2020-09-16 14:33:49 +02:00
mm	mm/memory-failure: make sure wait for page writeback in memory_failure	2021-06-23 14:42:40 +02:00
net	can: j1939: fix Use-after-Free, hold skb ref while in use	2021-06-23 14:42:50 +02:00
samples	samples: vfio-mdev: fix error handing in mdpy_fb_probe()	2021-06-10 13:39:15 +02:00
scripts	scripts/clang-tools: switch explicitly to Python 3	2021-06-03 09:00:52 +02:00
security	KEYS: trusted: Fix memory leak on object td	2021-05-19 10:12:50 +02:00
sound	ASoC: qcom: lpass-cpu: Fix pop noise during audio capture begin	2021-06-23 14:42:49 +02:00
tools	ipv4: Fix device used for dst_alloc with local routes	2021-06-23 14:42:45 +02:00
usr	Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2020-08-07 13:29:39 -07:00
virt	Revert "irqbypass: do not start cons/prod when failed connect"	2021-06-03 09:00:34 +02:00
.clang-format	RDMA 5.10 pull request	2020-10-17 11:18:18 -07:00
.cocciconfig	scripts: add Linux .cocciconfig for coccinelle	2016-07-22 12:13:39 +02:00
.get_maintainer.ignore	Opt out of scripts/get_maintainer.pl	2019-05-16 10:53:40 -07:00
.gitattributes	.gitattributes: use 'dts' diff driver for dts files	2019-12-04 19:44:11 -08:00
.gitignore	kbuild: generate Module.symvers only when vmlinux exists	2021-05-19 10:12:59 +02:00
.mailmap	mailmap: add two more addresses of Uwe Kleine-König	2020-12-06 10:19:07 -08:00
COPYING	COPYING: state that all contributions really are covered by this file	2020-02-10 13:32:20 -08:00
CREDITS	MAINTAINERS: Move Jason Cooper to CREDITS	2020-11-30 10:20:34 +01:00
Kbuild	kbuild: rename hostprogs-y/always to hostprogs/always-y	2020-02-04 01:53:07 +09:00
Kconfig	kbuild: ensure full rebuild when the compiler is updated	2020-05-12 13:28:33 +09:00
MAINTAINERS	f2fs: move ioctl interface definitions to separated file	2021-05-19 10:13:00 +02:00
Makefile	Linux 5.10.45	2021-06-18 10:00:06 +02:00
README	Drop all 00-INDEX files from Documentation/	2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.