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Filename Latest commit message Latest commit date
Sean Christopherson 796d3bd4ac KVM: x86: Ensure liveliness of nested VM-Enter fail tracepoint message
commit f31500b0d437a2464ca5972d8f5439e156b74960 upstream.

Use the __string() machinery provided by the tracing subystem to make a
copy of the string literals consumed by the "nested VM-Enter failed"
tracepoint.  A complete copy is necessary to ensure that the tracepoint
can't outlive the data/memory it consumes and deference stale memory.

Because the tracepoint itself is defined by kvm, if kvm-intel and/or
kvm-amd are built as modules, the memory holding the string literals
defined by the vendor modules will be freed when the module is unloaded,
whereas the tracepoint and its data in the ring buffer will live until
kvm is unloaded (or "indefinitely" if kvm is built-in).

This bug has existed since the tracepoint was added, but was recently
exposed by a new check in tracing to detect exactly this type of bug.

  fmt: '%s%s
  ' current_buffer: ' vmx_dirty_log_t-140127  [003] ....  kvm_nested_vmenter_failed: '
  WARNING: CPU: 3 PID: 140134 at kernel/trace/trace.c:3759 trace_check_vprintf+0x3be/0x3e0
  CPU: 3 PID: 140134 Comm: less Not tainted 5.13.0-rc1-ce2e73ce600a-req #184
  Hardware name: ASUS Q87M-E/Q87M-E, BIOS 1102 03/03/2014
  RIP: 0010:trace_check_vprintf+0x3be/0x3e0
  Code: <0f> 0b 44 8b 4c 24 1c e9 a9 fe ff ff c6 44 02 ff 00 49 8b 97 b0 20
  RSP: 0018:ffffa895cc37bcb0 EFLAGS: 00010282
  RAX: 0000000000000000 RBX: ffffa895cc37bd08 RCX: 0000000000000027
  RDX: 0000000000000027 RSI: 00000000ffffdfff RDI: ffff9766cfad74f8
  RBP: ffffffffc0a041d4 R08: ffff9766cfad74f0 R09: ffffa895cc37bad8
  R10: 0000000000000001 R11: 0000000000000001 R12: ffffffffc0a041d4
  R13: ffffffffc0f4dba8 R14: 0000000000000000 R15: ffff976409f2c000
  FS:  00007f92fa200740(0000) GS:ffff9766cfac0000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000559bd11b0000 CR3: 000000019fbaa002 CR4: 00000000001726e0
  Call Trace:
   trace_event_printf+0x5e/0x80
   trace_raw_output_kvm_nested_vmenter_failed+0x3a/0x60 [kvm]
   print_trace_line+0x1dd/0x4e0
   s_show+0x45/0x150
   seq_read_iter+0x2d5/0x4c0
   seq_read+0x106/0x150
   vfs_read+0x98/0x180
   ksys_read+0x5f/0xe0
   do_syscall_64+0x40/0xb0
   entry_SYSCALL_64_after_hwframe+0x44/0xae

Cc: Steven Rostedt <rostedt@goodmis.org>
Fixes: 380e0055bc ("KVM: nVMX: trace nested VM-Enter failures detected by H/W")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Message-Id: <20210607175748.674002-1-seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-16 11:59:44 +02:00
arch KVM: x86: Ensure liveliness of nested VM-Enter fail tracepoint message 2021-06-16 11:59:44 +02:00
block blk-mq: Swap two calls in blk_mq_exit_queue() 2021-05-19 10:08:30 +02:00
certs certs: Fix blacklist flag type confusion 2021-03-04 10:26:29 +01:00
crypto crypto: rng - fix crypto_rng_reset() refcounting when !CRYPTO_STATS 2021-05-11 14:04:15 +02:00
Documentation XArray: add xas_split 2021-06-10 13:37:14 +02:00
drivers RDMA/mlx4: Do not map the core_clock page to user space unless enabled 2021-06-16 11:59:44 +02:00
fs btrfs: promote debugging asserts to full-fledged checks in validate_super 2021-06-16 11:59:40 +02:00
include vmlinux.lds.h: Avoid orphan section with !SMP 2021-06-16 11:59:44 +02:00
init pid: take a reference when initializing cad_pid 2021-06-10 13:37:11 +02:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:20:16 +02:00
kernel sched/fair: Make sure to update tg contrib for blocked load 2021-06-16 11:59:44 +02:00
lib lib/lz4: explicitly support in-place decompression 2021-06-10 13:37:16 +02:00
LICENSES
mm mm/filemap: fix storing to a THP shadow entry 2021-06-10 13:37:15 +02:00
net RDS tcp loopback connection can hang 2021-06-16 11:59:35 +02:00
samples samples: vfio-mdev: fix error handing in mdpy_fb_probe() 2021-06-10 13:37:03 +02:00
scripts scripts: switch explicitly to Python 3 2021-05-22 11:38:30 +02:00
security security: commoncap: fix -Wstringop-overread warning 2021-05-11 14:04:16 +02:00
sound ASoC: sti-sas: add missing MODULE_DEVICE_TABLE 2021-06-16 11:59:33 +02:00
tools perf jevents: Fix getting maximum number of fds 2021-06-03 08:59:08 +02:00
usr
virt KVM: arm64: Initialize VCPU mdcr_el2 before loading it 2021-05-22 11:38:30 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Documentation/llvm: add documentation on building w/ Clang/LLVM 2020-08-26 10:40:46 +02:00
Makefile Linux 5.4.125 2021-06-10 13:37:17 +02:00
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.