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[lldb] Prevent race condition when fetching /proc/cpuinfo

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@clayborg found a potential race condition when setting a static
variable. The fix seems simply to use call_once.

All relevant tests pass.

Differential Revision: https://reviews.llvm.org/D131081
This commit is contained in:
Walter Erquinigo 2022-08-03 09:57:57 -07:00
parent 33af4b22f8
commit ddd576ab87
1 changed files with 9 additions and 12 deletions
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21
lldb/source/Plugins/Process/Linux/Procfs.cpp
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@ -7,9 +7,9 @@
//===----------------------------------------------------------------------===//
#include "Procfs.h"
#include "lldb/Host/linux/Support.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Threading.h"
using namespace lldb;
using namespace lldb_private;
@ -17,17 +17,14 @@ using namespace process_linux;
using namespace llvm;
Expected<ArrayRef<uint8_t>> lldb_private::process_linux::GetProcfsCpuInfo() {
static Optional<std::vector<uint8_t>> cpu_info;
if (!cpu_info) {
auto buffer_or_error = errorOrToExpected(getProcFile("cpuinfo"));
if (!buffer_or_error)
return buffer_or_error.takeError();
MemoryBuffer &buffer = **buffer_or_error;
cpu_info = std::vector<uint8_t>(
reinterpret_cast<const uint8_t *>(buffer.getBufferStart()),
reinterpret_cast<const uint8_t *>(buffer.getBufferEnd()));
}
return *cpu_info;
static ErrorOr<std::unique_ptr<MemoryBuffer>> cpu_info_or_err =
getProcFile("cpuinfo");
if (!*cpu_info_or_err)
cpu_info_or_err.getError();
MemoryBuffer &buffer = **cpu_info_or_err;
return arrayRefFromStringRef(buffer.getBuffer());
}
Expected<std::vector<cpu_id_t>>