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Marc Zyngier 599eee0e98 KVM: arm64: Don't eagerly teardown the vgic on init error 
commit df5fd75ee3 upstream.

As there is very little ordering in the KVM API, userspace can
instanciate a half-baked GIC (missing its memory map, for example)
at almost any time.

This means that, with the right timing, a thread running vcpu-0
can enter the kernel without a GIC configured and get a GIC created
behind its back by another thread. Amusingly, it will pick up
that GIC and start messing with the data structures without the
GIC having been fully initialised.

Similarly, a thread running vcpu-1 can enter the kernel, and try
to init the GIC that was previously created. Since this GIC isn't
properly configured (no memory map), it fails to correctly initialise.

And that's the point where we decide to teardown the GIC, freeing all
its resources. Behind vcpu-0's back. Things stop pretty abruptly,
with a variety of symptoms.  Clearly, this isn't good, we should be
a bit more careful about this.

It is obvious that this guest is not viable, as it is missing some
important part of its configuration. So instead of trying to tear
bits of it down, let's just mark it as *dead*. It means that any
further interaction from userspace will result in -EIO. The memory
will be released on the "normal" path, when userspace gives up.

Cc: stable@vger.kernel.org
Reported-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20241009183603.3221824-1-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2024-11-01 01:58:33 +01:00
arch KVM: arm64: Don't eagerly teardown the vgic on init error 2024-11-01 01:58:33 +01:00
block blk-rq-qos: fix crash on rq_qos_wait vs. rq_qos_wake_function race 2024-10-22 15:46:27 +02:00
certs certs: Reference revocation list for all keyrings 2023-08-17 20:12:41 +00:00
crypto crypto: simd - Do not call crypto_alloc_tfm during registration 2024-10-10 11:57:26 +02:00
Documentation ASoC: dt-bindings: davinci-mcasp: Fix interrupt properties 2024-11-01 01:58:31 +01:00
drivers ACPI: button: Add DMI quirk for Samsung Galaxy Book2 to fix initial lid detection issue 2024-11-01 01:58:32 +01:00
fs openat2: explicitly return -E2BIG for (usize > PAGE_SIZE) 2024-11-01 01:58:32 +01:00
include cpufreq/cppc: Move and rename cppc_cpufreq_{perf_to_khz|khz_to_perf}() 2024-11-01 01:58:32 +01:00
init rust: fix the default format for CONFIG_{RUSTC,BINDGEN}_VERSION_TEXT 2024-08-29 17:33:29 +02:00
io_uring io_uring/sqpoll: close race on waiting for sqring entries 2024-10-22 15:46:27 +02:00
ipc sysctl: treewide: drop unused argument ctl_table_root::set_ownership(table) 2024-08-11 12:47:13 +02:00
kernel bpf,perf: Fix perf_event_detach_bpf_prog error handling 2024-11-01 01:58:30 +01:00
lib lib/Kconfig.debug: fix grammar in RUST_BUILD_ASSERT_ALLOW 2024-11-01 01:58:18 +01:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm: khugepaged: fix the arguments order in khugepaged_collapse_file trace point 2024-11-01 01:58:26 +01:00
net Bluetooth: ISO: Fix UAF on iso_sock_timeout 2024-11-01 01:58:30 +01:00
rust rust: sync: require T: Sync for LockedBy::access 2024-10-10 11:57:44 +02:00
samples samples/bpf: Fix compilation errors with cf-protection option 2024-10-04 16:29:19 +02:00
scripts kconfig: qconf: fix buffer overflow in debug links 2024-10-10 11:58:01 +02:00
security tomoyo: fallback to realpath if symlink's pathname does not exist 2024-10-10 11:57:57 +02:00
sound ALSA: hda/realtek: Update default depop procedure 2024-11-01 01:58:31 +01:00
tools bpf: Simplify checking size of helper accesses 2024-11-01 01:58:29 +01:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt KVM: Use dedicated mutex to protect kvm_usage_count to avoid deadlock 2024-10-04 16:29:47 +02:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.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 Remove *.orig pattern from .gitignore 2024-10-04 16:29:44 +02:00
.mailmap 20 hotfixes. 12 are cc:stable and the remainder address post-6.5 issues 2023-10-24 09:52:16 -10:00
.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 USB: Remove Wireless USB and UWB documentation 2023-08-09 14:17:32 +02:00
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 membarrier: riscv: Add full memory barrier in switch_mm() 2024-09-12 11:11:45 +02:00
Makefile Linux 6.6.58 2024-10-22 15:46:36 +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.