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From 88c5af565882264c129816bdba94fed25c83f2de Mon Sep 17 00:00:00 2001
From: Mikhail Labiuk <m.labiuk@samsung.com>
Date: Mon, 19 Feb 2018 18:56:15 +0300
Subject: [PATCH 28/47] Do not allocate exception for signal from non managed
code
If the signal occurs in not managed code we cannot use heap.
We should call signal-safe functions only from signal handler.
Create exception object on stack for checking source of signal.
If signal is from managed code we can use memory allocation to create
persistent exception on heap as copy of volatile exception on stack.
If signal from unmanaged code we do nothing and call base signal handler.
fix https://github.com/dotnet/coreclr/issues/16338
---
src/pal/inc/pal.h | 5 ++++-
src/pal/src/exception/seh.cpp | 23 +++++++++++++++++++++++
src/pal/src/exception/signal.cpp | 30 +++++++++++++++---------------
3 files changed, 42 insertions(+), 16 deletions(-)
diff --git a/src/pal/inc/pal.h b/src/pal/inc/pal.h
index 0a00b67..e3bfa40 100644
--- a/src/pal/inc/pal.h
+++ b/src/pal/inc/pal.h
@@ -3888,6 +3888,8 @@ PAL_BindResources(IN LPCSTR lpDomain);
#define EXCEPTION_IS_SIGNAL 0x100
+#define EXCEPTION_ON_STACK 0x400
+
#define EXCEPTION_MAXIMUM_PARAMETERS 15
// Index in the ExceptionInformation array where we will keep the reference
@@ -5814,7 +5816,8 @@ private:
void FreeRecords()
{
- if (ExceptionPointers.ExceptionRecord != NULL)
+ if (ExceptionPointers.ExceptionRecord != NULL &&
+ ! (ExceptionPointers.ExceptionRecord->ExceptionFlags | EXCEPTION_ON_STACK) )
{
PAL_FreeExceptionRecords(ExceptionPointers.ExceptionRecord, ExceptionPointers.ContextRecord);
ExceptionPointers.ExceptionRecord = NULL;
diff --git a/src/pal/src/exception/seh.cpp b/src/pal/src/exception/seh.cpp
index 0574fad..a7d4ad9 100644
--- a/src/pal/src/exception/seh.cpp
+++ b/src/pal/src/exception/seh.cpp
@@ -232,6 +232,23 @@ void ThrowExceptionHelper(PAL_SEHException* ex)
throw std::move(*ex);
}
+static PAL_SEHException copyPAL_SEHException(PAL_SEHException* src)
+{
+ CONTEXT* contextRecord = src->GetContextRecord();
+ EXCEPTION_RECORD* exceptionRecord = src->GetExceptionRecord();
+
+ CONTEXT* contextRecordCopy;
+ EXCEPTION_RECORD* exceptionRecordCopy;
+ AllocateExceptionRecords(&exceptionRecordCopy, &contextRecordCopy);
+
+ *exceptionRecordCopy = *exceptionRecord;
+ exceptionRecordCopy->ExceptionFlags &= ~EXCEPTION_ON_STACK;
+ *contextRecordCopy = *contextRecord;
+ return PAL_SEHException(exceptionRecordCopy, contextRecordCopy);
+}
+
+
+
/*++
Function:
SEHProcessException
@@ -279,6 +296,9 @@ SEHProcessException(PAL_SEHException* exception)
PROCAbort();
}
}
+
+ if(exceptionRecord->ExceptionFlags | EXCEPTION_ON_STACK)
+ *exception = copyPAL_SEHException(exception);
if (g_hardwareExceptionHandler(exception))
{
@@ -292,6 +312,9 @@ SEHProcessException(PAL_SEHException* exception)
if (CatchHardwareExceptionHolder::IsEnabled())
{
+ if(exceptionRecord->ExceptionFlags | EXCEPTION_ON_STACK)
+ *exception = copyPAL_SEHException(exception);
+
PAL_ThrowExceptionFromContext(exception->GetContextRecord(), exception);
}
}
diff --git a/src/pal/src/exception/signal.cpp b/src/pal/src/exception/signal.cpp
index bf48619..d42ba38 100644
--- a/src/pal/src/exception/signal.cpp
+++ b/src/pal/src/exception/signal.cpp
@@ -801,32 +801,32 @@ static bool common_signal_handler(int code, siginfo_t *siginfo, void *sigcontext
{
sigset_t signal_set;
CONTEXT signalContextRecord;
- CONTEXT *contextRecord;
- EXCEPTION_RECORD *exceptionRecord;
+ CONTEXT contextRecord;
+ EXCEPTION_RECORD exceptionRecord;
native_context_t *ucontext;
ucontext = (native_context_t *)sigcontext;
g_common_signal_handler_context_locvar_offset = (int)((char*)&signalContextRecord - (char*)__builtin_frame_address(0));
- AllocateExceptionRecords(&exceptionRecord, &contextRecord);
+ //AllocateExceptionRecords(&exceptionRecord, &contextRecord);
- exceptionRecord->ExceptionCode = CONTEXTGetExceptionCodeForSignal(siginfo, ucontext);
- exceptionRecord->ExceptionFlags = EXCEPTION_IS_SIGNAL;
- exceptionRecord->ExceptionRecord = NULL;
- exceptionRecord->ExceptionAddress = GetNativeContextPC(ucontext);
- exceptionRecord->NumberParameters = numParams;
+ exceptionRecord.ExceptionCode = CONTEXTGetExceptionCodeForSignal(siginfo, ucontext);
+ exceptionRecord.ExceptionFlags = EXCEPTION_IS_SIGNAL | EXCEPTION_ON_STACK;
+ exceptionRecord.ExceptionRecord = NULL;
+ exceptionRecord.ExceptionAddress = GetNativeContextPC(ucontext);
+ exceptionRecord.NumberParameters = numParams;
va_list params;
va_start(params, numParams);
for (int i = 0; i < numParams; i++)
{
- exceptionRecord->ExceptionInformation[i] = va_arg(params, size_t);
+ exceptionRecord.ExceptionInformation[i] = va_arg(params, size_t);
}
// Pre-populate context with data from current frame, because ucontext doesn't have some data (e.g. SS register)
// which is required for restoring context
- RtlCaptureContext(contextRecord);
+ RtlCaptureContext(&contextRecord);
ULONG contextFlags = CONTEXT_CONTROL | CONTEXT_INTEGER | CONTEXT_FLOATING_POINT;
@@ -837,7 +837,7 @@ static bool common_signal_handler(int code, siginfo_t *siginfo, void *sigcontext
// Fill context record with required information. from pal.h:
// On non-Win32 platforms, the CONTEXT pointer in the
// PEXCEPTION_POINTERS will contain at least the CONTEXT_CONTROL registers.
- CONTEXTFromNativeContext(ucontext, contextRecord, contextFlags);
+ CONTEXTFromNativeContext(ucontext, &contextRecord, contextFlags);
/* Unmask signal so we can receive it again */
sigemptyset(&signal_set);
@@ -848,17 +848,17 @@ static bool common_signal_handler(int code, siginfo_t *siginfo, void *sigcontext
ASSERT("pthread_sigmask failed; error number is %d\n", sigmaskRet);
}
- contextRecord->ContextFlags |= CONTEXT_EXCEPTION_ACTIVE;
+ contextRecord.ContextFlags |= CONTEXT_EXCEPTION_ACTIVE;
- memcpy_s(&signalContextRecord, sizeof(CONTEXT), contextRecord, sizeof(CONTEXT));
+ memcpy_s(&signalContextRecord, sizeof(CONTEXT), &contextRecord, sizeof(CONTEXT));
// The exception object takes ownership of the exceptionRecord and contextRecord
- PAL_SEHException exception(exceptionRecord, contextRecord);
+ PAL_SEHException exception(&exceptionRecord, &contextRecord);
if (SEHProcessException(&exception))
{
// Exception handling may have modified the context, so update it.
- CONTEXTToNativeContext(contextRecord, ucontext);
+ CONTEXTToNativeContext(&contextRecord, ucontext);
return true;
}
--
2.7.4
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