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From 97b80457b091641dd6fb366038b8e362b1409a58 Mon Sep 17 00:00:00 2001
From: Mikhail Labiuk <m.labiuk@samsung.com>
Date: Tue, 13 Feb 2018 15:02:12 +0300
Subject: [PATCH 26/47] Prevent memory allocation in signal handler
If the signal occurs when heap being inconsistent we should not
use heap. We should call signal-safe functions only from signal handler.
fix https://github.com/dotnet/coreclr/issues/16338
---
src/pal/src/exception/seh-unwind.cpp | 6 ++++--
src/pal/src/exception/signal.cpp | 2 +-
src/pal/src/include/pal/seh.hpp | 3 ++-
3 files changed, 7 insertions(+), 4 deletions(-)
diff --git a/src/pal/src/exception/seh-unwind.cpp b/src/pal/src/exception/seh-unwind.cpp
index 7746bbb..eba2c80 100644
--- a/src/pal/src/exception/seh-unwind.cpp
+++ b/src/pal/src/exception/seh-unwind.cpp
@@ -620,12 +620,14 @@ Function:
Parameters:
exceptionRecord - output pointer to the allocated exception record
contextRecord - output pointer to the allocated context record
+ allocationProhibited - input flag to avoid memory allocation in critical situations
--*/
VOID
-AllocateExceptionRecords(EXCEPTION_RECORD** exceptionRecord, CONTEXT** contextRecord)
+AllocateExceptionRecords(EXCEPTION_RECORD** exceptionRecord, CONTEXT** contextRecord, BOOL allocationProhibited)
{
ExceptionRecords* records;
- if (posix_memalign((void**)&records, alignof(ExceptionRecords), sizeof(ExceptionRecords)) != 0)
+ if (allocationProhibited ||
+ (posix_memalign((void**)&records, alignof(ExceptionRecords), sizeof(ExceptionRecords)) != 0) )
{
size_t bitmap;
size_t newBitmap;
diff --git a/src/pal/src/exception/signal.cpp b/src/pal/src/exception/signal.cpp
index bf48619..90da207 100644
--- a/src/pal/src/exception/signal.cpp
+++ b/src/pal/src/exception/signal.cpp
@@ -808,7 +808,7 @@ static bool common_signal_handler(int code, siginfo_t *siginfo, void *sigcontext
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, true);
exceptionRecord->ExceptionCode = CONTEXTGetExceptionCodeForSignal(siginfo, ucontext);
exceptionRecord->ExceptionFlags = EXCEPTION_IS_SIGNAL;
diff --git a/src/pal/src/include/pal/seh.hpp b/src/pal/src/include/pal/seh.hpp
index 3ac93d6..5edc214 100644
--- a/src/pal/src/include/pal/seh.hpp
+++ b/src/pal/src/include/pal/seh.hpp
@@ -84,9 +84,10 @@ Function:
Parameters:
exceptionRecord - output pointer to the allocated Windows exception record
contextRecord - output pointer to the allocated Windows context record
+ allocationProhibited - input flag to avoid memory allocation in critical situations
--*/
VOID
-AllocateExceptionRecords(EXCEPTION_RECORD** exceptionRecord, CONTEXT** contextRecord);
+AllocateExceptionRecords(EXCEPTION_RECORD** exceptionRecord, CONTEXT** contextRecord, BOOL allocationProhibited=false);
#if !HAVE_MACH_EXCEPTIONS
// TODO: Implement for Mach exceptions. Not in CoreCLR surface area.
--
2.7.4
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