kernel_optimize_test/arch
Sean Christopherson d046f724bb 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 12:01:46 +02:00
..
alpha local64.h: make <asm/local64.h> mandatory 2021-01-12 20:18:16 +01:00
arc ARC: mm: Use max_high_pfn as a HIGHMEM zone border 2021-05-19 10:13:10 +02:00
arm ARM: cpuidle: Avoid orphan section warning 2021-06-16 12:01:44 +02:00
arm64 KVM: arm64: Fix debug register indexing 2021-06-10 13:39:28 +02:00
c6x arch-cleanup-2020-10-22 2020-10-23 10:06:38 -07:00
csky csky: change a Kconfig symbol name to fix e1000 build error 2021-04-28 13:40:02 +02:00
h8300 h8300: fix PREEMPTION build, TI_PRE_COUNT undefined 2021-02-17 11:02:28 +01:00
hexagon local64.h: make <asm/local64.h> mandatory 2021-01-12 20:18:16 +01:00
ia64 tweewide: Fix most Shebang lines 2021-05-22 11:40:55 +02:00
m68k m68k: Add missing mmap_read_lock() to sys_cacheflush() 2021-05-14 09:50:19 +02:00
microblaze local64.h: make <asm/local64.h> mandatory 2021-01-12 20:18:16 +01:00
mips MIPS: Fix kernel hang under FUNCTION_GRAPH_TRACER and PREEMPT_TRACER 2021-06-16 12:01:37 +02:00
nds32 nds32: flush_dcache_page: use page_mapping_file to avoid races with swapoff 2021-04-14 08:41:58 +02:00
nios2 nios2: fixed broken sys_clone syscall 2021-03-04 11:38:16 +01:00
openrisc openrisc: Define memory barrier mb 2021-06-03 09:00:44 +02:00
parisc parisc: avoid a warning on u8 cast for cmpxchg on u8 pointers 2021-04-14 08:41:59 +02:00
powerpc powerpc/fsl: set fsl,i2c-erratum-a004447 flag for P1010 i2c controllers 2021-06-16 12:01:38 +02:00
riscv riscv: vdso: fix and clean-up Makefile 2021-06-10 13:39:22 +02:00
s390 KVM: s390: extend kvm_s390_shadow_fault to return entry pointer 2021-05-14 09:50:03 +02:00
sh sh: Remove unused HAVE_COPY_THREAD_TLS macro 2021-01-27 11:55:20 +01:00
sparc sparc64: Fix opcode filtering in handling of no fault loads 2021-03-30 14:31:50 +02:00
um um: Disable CONFIG_GCOV with MODULES 2021-05-22 11:40:53 +02:00
x86 KVM: x86: Ensure liveliness of nested VM-Enter fail tracepoint message 2021-06-16 12:01:46 +02:00
xtensa xtensa: move coprocessor_flush to the .text section 2021-04-07 15:00:09 +02:00
.gitignore
Kconfig fanotify: Fix sys_fanotify_mark() on native x86-32 2021-01-17 14:16:59 +01:00