Date: Wed, 11 May 2005 11:19:22 +0200 (CEST) From: "Arne H. Juul" <arnej@pvv.ntnu.no> To: freebsd-java@freebsd.org Subject: Re: JDK 1.5.0: application crash with multiple threads Message-ID: <Pine.LNX.4.62.0505111057070.23037@decibel.pvv.ntnu.no>
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On Fri, Apr 08, 2005 at 10:22:31AM -0400, Brian Clapper wrote:
> I have a multithreaded application that is crashing under JDK 1.5.0 when
> using multiple threads. Works fine (and has worked fine for quite some
> time) with JDK 1.4.2.
I've spent some days tracing down this problem, and found this fix:
diff -ru jdk15.orig/hotspot/src/os/bsd/vm/os_bsd.inline.hpp jdk15/hotspot/src/os/bsd/vm/os_bsd.inline.hpp
--- jdk15.orig/hotspot/src/os/bsd/vm/os_bsd.inline.hpp Wed May 11 10:59:36 2005
+++ jdk15/hotspot/src/os/bsd/vm/os_bsd.inline.hpp Wed May 11 08:03:59 2005
@@ -29,10 +29,9 @@
inline bool os::allocate_stack_guard_pages() {
assert(uses_stack_guard_pages(), "sanity check");
-// XXXBSD: ??
-// return thr_main();
-// return pthread_main_np();
- return true;
+ // since FreeBSD 4 uses malloc() for allocating the thread stack
+ // there is no need to do anything extra to allocate the guard pages
+ return false;
}
What happens is this:
When a thread is started the stack is allocated via malloc(),
and then the bottom is the stack is again "allocated" via
commit_memory() and protected via guard_memory(). When the
thread is done it is "freed" via uncommit_memory() which mmaps
the memory with PROT_NONE, and then it is free()d as well.
Soon, when malloc() is used (for something else) it returns
a pointer into this region and when that pointer is used SIGBUS
happens. The only reason this works in the java14 port is
that uncommit_memory() doesn't do what it is supposed to there.
--
Arne H Juul Mail: arnej@europe.yahoo-inc.com
Release engineer Web: http://www.yahoo.com/
Yahoo Norway Phone: +47 7320 1219
Prinsensgate 49, 7013 Trondheim Fax: +47 7320 1201
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