Gabe Black has submitted this change and it was merged. (
https://gem5-review.googlesource.com/c/public/gem5/+/14395 )
Change subject: base: Set up a guard page for fiber stacks.
......................................................................
base: Set up a guard page for fiber stacks.
This will help detect stack overflow for fibers.
Change-Id: Iff2b102120ec351709e495291d6bead597f8d10c
Reviewed-on: https://gem5-review.googlesource.com/c/14395
Reviewed-by: Daniel Carvalho <[email protected]>
Maintainer: Gabe Black <[email protected]>
---
M src/base/fiber.cc
M src/base/fiber.hh
2 files changed, 33 insertions(+), 14 deletions(-)
Approvals:
Daniel Carvalho: Looks good to me, approved
Gabe Black: Looks good to me, approved
diff --git a/src/base/fiber.cc b/src/base/fiber.cc
index eac1d93..af63216 100644
--- a/src/base/fiber.cc
+++ b/src/base/fiber.cc
@@ -33,7 +33,11 @@
#include <valgrind/valgrind.h>
#endif
+#include <sys/mman.h>
+#include <unistd.h>
+
#include <cerrno>
+#include <cstdio>
#include <cstring>
#include "base/logging.hh"
@@ -71,20 +75,32 @@
startingFiber->start();
}
-Fiber::Fiber(size_t stack_size) :
- link(primaryFiber()),
- stack(stack_size ? new uint8_t[stack_size] : nullptr),
- stackSize(stack_size), started(false), _finished(false)
-{
-#if HAVE_VALGRIND
- valgrindStackId = VALGRIND_STACK_REGISTER(stack, stack + stack_size);
-#endif
-}
+Fiber::Fiber(size_t stack_size) : Fiber(primaryFiber(), stack_size)
+{}
Fiber::Fiber(Fiber *link, size_t stack_size) :
- link(link), stack(stack_size ? new uint8_t[stack_size] : nullptr),
- stackSize(stack_size), started(false), _finished(false)
-{}
+ link(link), stack(nullptr), stackSize(stack_size), guardPage(nullptr),
+ guardPageSize(sysconf(_SC_PAGE_SIZE)), started(false), _finished(false)
+{
+ if (stack_size) {
+ guardPage = mmap(nullptr, guardPageSize + stack_size,
+ PROT_READ | PROT_WRITE,
+ MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+ if (guardPage == (void *)MAP_FAILED) {
+ perror("mmap");
+ fatal("Could not mmap %d byte fiber stack.\n", stack_size);
+ }
+ stack = (void *)((uint8_t *)guardPage + guardPageSize);
+ if (mprotect(guardPage, guardPageSize, PROT_NONE)) {
+ perror("mprotect");
+ fatal("Could not forbid access to fiber stack guard page.");
+ }
+ }
+#if HAVE_VALGRIND
+ valgrindStackId = VALGRIND_STACK_REGISTER(
+ stack, (uint8_t *)stack + stack_size);
+#endif
+}
Fiber::~Fiber()
{
@@ -92,7 +108,8 @@
#if HAVE_VALGRIND
VALGRIND_STACK_DEREGISTER(valgrindStackId);
#endif
- delete [] stack;
+ if (guardPage)
+ munmap(guardPage, guardPageSize + stackSize);
}
void
diff --git a/src/base/fiber.hh b/src/base/fiber.hh
index 3d82075..4d95e03 100644
--- a/src/base/fiber.hh
+++ b/src/base/fiber.hh
@@ -106,8 +106,10 @@
Fiber *link;
// The stack for this context, or a nullptr if allocated elsewhere.
- uint8_t *stack;
+ void *stack;
size_t stackSize;
+ void *guardPage;
+ size_t guardPageSize;
#if HAVE_VALGRIND
unsigned valgrindStackId;
#endif
--
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Gerrit-Project: public/gem5
Gerrit-Branch: master
Gerrit-Change-Id: Iff2b102120ec351709e495291d6bead597f8d10c
Gerrit-Change-Number: 14395
Gerrit-PatchSet: 3
Gerrit-Owner: Gabe Black <[email protected]>
Gerrit-Reviewer: Andreas Sandberg <[email protected]>
Gerrit-Reviewer: Daniel Carvalho <[email protected]>
Gerrit-Reviewer: Gabe Black <[email protected]>
Gerrit-Reviewer: Giacomo Travaglini <[email protected]>
Gerrit-Reviewer: Jason Lowe-Power <[email protected]>
Gerrit-MessageType: merged
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