Date: Tue, 28 Sep 2004 22:30:28 GMT From: Dan Nelson <dnelson@allantgroup.com> To: freebsd-java@FreeBSD.org Subject: Re: java/72151: JVM crash on 5.2.1-R Message-ID: <200409282230.i8SMUSd2020092@freefall.freebsd.org>
next in thread | raw e-mail | index | archive | help
The following reply was made to PR java/72151; it has been noted by GNATS.
From: Dan Nelson <dnelson@allantgroup.com>
To: Andrzej Bialecki <ab@getopt.org>
Cc: freebsd-gnats-submit@FreeBSD.org
Subject: Re: java/72151: JVM crash on 5.2.1-R
Date: Tue, 28 Sep 2004 17:21:58 -0500
In the last episode (Sep 28), Andrzej Bialecki said:
> Running an application for Internet search engine (www.nutch.org). JDK built from ports:
>
> # java -version
> java version "1.4.2-p6"
> Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2-p6-root_21_sep_2004_22_20)
> Java HotSpot(TM) Client VM (build 1.4.2-p6-root_21_sep_2004_22_20, mixed mode)
>
> When executing a multi-threaded crawl (~50 threads), and running it for a couple of hours, JVM crashes with the following error log:
>
> An unexpected exception has been detected in native code outside the VM.
> Unexpected Signal : 11 occurred at PC=0x28151624
> Function=flockfile+0x24
> Library=/lib/libc.so.5
>
> Current Java thread:
> at java.net.Inet4AddressImpl.lookupAllHostAddr(Native Method)
This is because java is calling gethostent() which is not thread-safe
(POSIX does not require it to be, either). It uses a global "hostf"
FILE* to read /etc/hosts, so multiple threads doing DNS lookups will
almost certainly trash each other. My quick hack is this, which
returns a DNS error if hostf ends up NULL. A better fix would be to
add a mutex around the DNS routines in
Inet4AddressImpl.lookupAllHostAddr.
Index: gethostbyht.c
===================================================================
RCS file: /home/ncvs/src/lib/libc/net/gethostbyht.c,v
retrieving revision 1.16
diff -u -p -r1.16 gethostbyht.c
--- gethostbyht.c 22 Mar 2002 21:52:29 -0000 1.16
+++ gethostbyht.c 3 Aug 2004 16:43:02 -0000
@@ -112,6 +112,10 @@ gethostent()
return (NULL);
}
again:
+ if (!hostf) {
+ h_errno = NETDB_INTERNAL;
+ return (NULL);
+ }
if (!(p = fgets(hostbuf, sizeof hostbuf, hostf))) {
h_errno = HOST_NOT_FOUND;
return (NULL);
--
Dan Nelson
dnelson@allantgroup.com
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200409282230.i8SMUSd2020092>