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Sean Christopherson 3f2739bd1e KVM: x86: Acquire SRCU read lock when handling fastpath MSR writes
Temporarily acquire kvm->srcu for read when potentially emulating WRMSR in
the VM-Exit fastpath handler, as several of the common helpers used during
emulation expect the caller to provide SRCU protection.  E.g. if the guest
is counting instructions retired, KVM will query the PMU event filter when
stepping over the WRMSR.

  dump_stack+0x85/0xdf
  lockdep_rcu_suspicious+0x109/0x120
  pmc_event_is_allowed+0x165/0x170
  kvm_pmu_trigger_event+0xa5/0x190
  handle_fastpath_set_msr_irqoff+0xca/0x1e0
  svm_vcpu_run+0x5c3/0x7b0 [kvm_amd]
  vcpu_enter_guest+0x2108/0x2580

Alternatively, check_pmu_event_filter() could acquire kvm->srcu, but this
isn't the first bug of this nature, e.g. see commit 5c30e8101e ("KVM:
SVM: Skip WRMSR fastpath on VM-Exit if next RIP isn't valid").  Providing
protection for the entirety of WRMSR emulation will allow reverting the
aforementioned commit, and will avoid having to play whack-a-mole when new
uses of SRCU-protected structures are inevitably added in common emulation
helpers.

Fixes: dfdeda67ea ("KVM: x86/pmu: Prevent the PMU from counting disallowed events")
Reported-by: Greg Thelen <gthelen@google.com>
Reported-by: Aaron Lewis <aaronlewis@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230721224337.2335137-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-07-29 11:05:27 -04:00
arch KVM: x86: Acquire SRCU read lock when handling fastpath MSR writes 2023-07-29 11:05:27 -04:00
block block-6.5-2023-07-21 2023-07-22 11:05:15 -07:00
certs KEYS: Add missing function documentation 2023-04-24 16:15:52 +03:00
crypto crypto: algif_hash - Fix race between MORE and non-MORE sends 2023-07-08 22:48:42 +10:00
Documentation Devicetree fixes for v6.5: 2023-07-22 10:28:22 -07:00
drivers s390 fixes for 6.5-rc3 2023-07-22 11:24:03 -07:00
fs Bug and regression fixes for 6.5-rc3 for ext4's mballoc and jbd2's 2023-07-23 10:21:49 -07:00
include ARM: 2023-07-23 10:44:38 -07:00
init Kbuild updates for v6.5 2023-07-01 09:24:31 -07:00
io_uring io_uring-6.5-2023-07-21 2023-07-22 10:46:30 -07:00
ipc Merge branch 'work.namespace' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2023-02-24 19:20:07 -08:00
kernel Tracing fixes for 6.5-rc2: 2023-07-23 15:19:14 -07:00
lib block-6.5-2023-07-21 2023-07-22 11:05:15 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm/mlock: fix vma iterator conversion of apply_vma_lock_flags() 2023-07-17 12:53:21 -07:00
net Including fixes from BPF, netfilter, bluetooth and CAN. 2023-07-20 14:46:39 -07:00
rust rust: error: impl Debug for Error with errname() integration 2023-06-13 01:24:42 +02:00
samples arm64: ftrace: Add direct call trampoline samples support 2023-07-10 17:51:54 -04:00
scripts Kbuild fixes for v6.5 2023-07-23 14:55:41 -07:00
security security: keys: Modify mismatched function name 2023-07-17 19:40:27 +00:00
sound ASoC: Fixes for v6.5 2023-07-20 15:16:11 +02:00
tools sound fixes for 6.5-rc3 2023-07-21 10:10:18 -07:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt ARM64: 2023-07-03 15:32:22 -07:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Revert ".gitignore: ignore *.cover and *.mbx" 2023-07-04 15:05:12 -07:00
.mailmap Including fixes from BPF, netfilter, bluetooth and CAN. 2023-07-20 14:46:39 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS - Address -Wmissing-prototype warnings 2023-06-26 16:43:54 -07:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS ASoC: Fixes for v6.5 2023-07-17 08:21:09 +02:00
Makefile Linux 6.5-rc3 2023-07-23 15:24:10 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.