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8267908: linux: thread_native_entry can scribble on stack frame

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Reviewed-by: ysuenaga
This commit is contained in:
David Holmes 2021-06-08 04:53:02 +00:00
parent f40c89e8e9
commit 341f676066
1 changed files with 2 additions and 1 deletions
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3
src/hotspot/os/linux/os_linux.cpp
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@ -672,7 +672,8 @@ static void *thread_native_entry(Thread *thread) {
// and we did not see any degradation in performance without `alloca()`. // and we did not see any degradation in performance without `alloca()`.
static int counter = 0; static int counter = 0;
int pid = os::current_process_id(); int pid = os::current_process_id();
void *stackmem = alloca(((pid ^ counter++) & 7) * 128); int random = ((pid ^ counter++) & 7) * 128;
void *stackmem = alloca(random != 0 ? random : 1); // ensure we allocate > 0
// Ensure the alloca result is used in a way that prevents the compiler from eliding it. // Ensure the alloca result is used in a way that prevents the compiler from eliding it.
*(char *)stackmem = 1; *(char *)stackmem = 1;
#endif #endif