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<span style="color: rgb(0, 36, 81);">Thanks </span><span style="color: rgb(0, 36, 81);">Kim</span><span style="color: rgb(0, 36, 81);">! Yes, I agree with you it should be caused by bad objects because of every crash always reported the same invalid address
0x000000008. This issue only happens when running a tool called </span><span style="color: rgb(0, 36, 81);">smartctl</span><span style="color: rgb(0, 36, 81);">. It is hard to believe a process can corrupt other's process's heap. Only observation is when </span><span style="font-family: Calibri, Helvetica, sans-serif; background-color: rgb(255, 255, 255); display: inline !important;"><span style="color: rgb(0, 36, 81);">smartctl</span></span><span style="font-family: Calibri, Helvetica, sans-serif; background-color: rgb(255, 255, 255); display: inline !important; color: rgb(0, 36, 81);"> is
running, a high IO usage is seen. The Linux IO may use a lot of memory for caching which puts the JVM process memory pressure. But still, I don't understand how it can cause other process's heap corruption. </span></div>
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<span style="font-family: Calibri, Helvetica, sans-serif; background-color: rgb(255, 255, 255); display: inline !important; color: rgb(0, 36, 81);">I am very interested in finding patterns and </span><span style="font-family: Calibri, Helvetica, sans-serif; background-color: rgb(255, 255, 255); display: inline !important"><span style="color: rgb(0, 36, 81); font-family: "Microsoft Yahei UI", Verdana, Simsun, "Segoe UI", -apple-system, system-ui, Roboto, "Helvetica Neue", sans-serif; font-size: 14.6667px; background-color: rgb(255, 255, 255); display: inline !important;">instrumenting
the JVM code. Can you explain a little or point me some wiki about "</span><span style="color: rgb(51, 51, 51); font-family: "Microsoft Yahei UI", Verdana, Simsun, "Segoe UI", -apple-system, system-ui, Roboto, "Helvetica Neue", sans-serif; font-size: 14.6667px; background-color: rgb(255, 255, 255); display: inline !important"><span style="font-family: "Microsoft Yahei UI", Verdana, Simsun, "Segoe UI", -apple-system, system-ui, Roboto, "Helvetica Neue", sans-serif; background-color: rgb(255, 255, 255); display: inline !important; color: rgb(0, 36, 81);">special
patterns like 0xdeadbeef</span><span style="font-family: "Microsoft Yahei UI", Verdana, Simsun, "Segoe UI", -apple-system, system-ui, Roboto, "Helvetica Neue", sans-serif; background-color: rgb(255, 255, 255); display: inline !important"><span style="color: rgb(0, 36, 81);"> "? </span></span></span></span></div>
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<span style="font-family: Calibri, Helvetica, sans-serif; background-color: rgb(255, 255, 255); display: inline !important"><span style="color: rgb(51, 51, 51); font-family: "Microsoft Yahei UI", Verdana, Simsun, "Segoe UI", -apple-system, system-ui, Roboto, "Helvetica Neue", sans-serif; font-size: 14.6667px; background-color: rgb(255, 255, 255); display: inline !important"><span style="font-family: "Microsoft Yahei UI", Verdana, Simsun, "Segoe UI", -apple-system, system-ui, Roboto, "Helvetica Neue", sans-serif; background-color: rgb(255, 255, 255); display: inline !important"><span><br>
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<span style="font-family: Calibri, Helvetica, sans-serif; background-color: rgb(255, 255, 255); display: inline !important"><span style="color: rgb(51, 51, 51); font-family: "Microsoft Yahei UI", Verdana, Simsun, "Segoe UI", -apple-system, system-ui, Roboto, "Helvetica Neue", sans-serif; font-size: 14.6667px; background-color: rgb(255, 255, 255); display: inline !important"><span style="font-family: "Microsoft Yahei UI", Verdana, Simsun, "Segoe UI", -apple-system, system-ui, Roboto, "Helvetica Neue", sans-serif; background-color: rgb(255, 255, 255); display: inline !important"><span style="color: rgb(0, 36, 81);">Also,
can you point me where is the code path I can </span><span><span style="font-family: "Microsoft Yahei UI", Verdana, Simsun, "Segoe UI", -apple-system, system-ui, Roboto, "Helvetica Neue", sans-serif; background-color: rgb(255, 255, 255); display: inline !important; color: rgb(0, 36, 81);">instrument
for the path for scanning and pushing object into </span><span style="font-family: "Microsoft Yahei UI", Verdana, Simsun, "Segoe UI", -apple-system, system-ui, Roboto, "Helvetica Neue", sans-serif; background-color: rgb(255, 255, 255); display: inline !important"><span style="color: rgb(0, 36, 81);" class="">queue</span><span style="color: rgb(0, 36, 81);">.</span></span><span style="font-family: "Microsoft Yahei UI", Verdana, Simsun, "Segoe UI", -apple-system, system-ui, Roboto, "Helvetica Neue", sans-serif; background-color: rgb(255, 255, 255); display: inline !important; color: rgb(0, 36, 81);"> </span></span></span></span></span></div>
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<span style="font-family: Calibri, Helvetica, sans-serif; background-color: rgb(255, 255, 255); display: inline !important"><span style="color: rgb(51, 51, 51); font-family: "Microsoft Yahei UI", Verdana, Simsun, "Segoe UI", -apple-system, system-ui, Roboto, "Helvetica Neue", sans-serif; font-size: 14.6667px; background-color: rgb(255, 255, 255); display: inline !important"><span style="font-family: "Microsoft Yahei UI", Verdana, Simsun, "Segoe UI", -apple-system, system-ui, Roboto, "Helvetica Neue", sans-serif; background-color: rgb(255, 255, 255); display: inline !important"><span><span style="font-family: "Microsoft Yahei UI", Verdana, Simsun, "Segoe UI", -apple-system, system-ui, Roboto, "Helvetica Neue", sans-serif; background-color: rgb(255, 255, 255); display: inline !important"><br>
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<span style="font-family: Calibri, Helvetica, sans-serif; background-color: rgb(255, 255, 255); display: inline !important"><span style="color: rgb(51, 51, 51); font-family: "Microsoft Yahei UI", Verdana, Simsun, "Segoe UI", -apple-system, system-ui, Roboto, "Helvetica Neue", sans-serif; font-size: 14.6667px; background-color: rgb(255, 255, 255); display: inline !important"><span style="font-family: "Microsoft Yahei UI", Verdana, Simsun, "Segoe UI", -apple-system, system-ui, Roboto, "Helvetica Neue", sans-serif; background-color: rgb(255, 255, 255); display: inline !important"><span><span style="font-family: "Microsoft Yahei UI", Verdana, Simsun, "Segoe UI", -apple-system, system-ui, Roboto, "Helvetica Neue", sans-serif; background-color: rgb(255, 255, 255); display: inline !important; color: rgb(0, 36, 81);">Xinli </span></span></span></span></span></div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>发件人:</b> Kim Barrett <kim.barrett@oracle.com><br>
<b>发送时间:</b> 2019年4月5日 12:15<br>
<b>收件人:</b> shang xinli<br>
<b>抄送:</b> hotspot-gc-dev@openjdk.java.net<br>
<b>主题:</b> Re: JVM crashes constantly when High GC happens</font>
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<div class="PlainText">> On Apr 4, 2019, at 10:16 PM, shang xinli <shangxinli@hotmail.com> wrote:<br>
> <br>
> Hi all,<br>
> <br>
> We hit crashes pretty constantly when the GC is high when using CMS GC. We switched to G1GC but it still crashes at the same places. It also crashes with the newest version of JDK. Anybody has a clue how to investigate why?
<br>
<br>
What's happening here is a segfault in oopDesc::size(), apparently<br>
obtaining the klass() of the object. This suggests a corrupted object<br>
or a NULL that was expected to be a real object. Since you report it<br>
happens with different collectors (both CMS and G1), that suggests it<br>
may not be a GC bug, but rather something else is corrupting the heap.<br>
<br>
Try to examine the data involved with a debugger (either live or from<br>
a core dump); there might be clues there, especially if there are any<br>
special patterns like 0xdeadbeef and the like involved.<br>
<br>
It looks like the bad object was obtained from the mark queue, which<br>
suggests it's either in a GC root or some other object refers to it.<br>
If there's any pattern to the bad value, and you can't find where it's<br>
coming from any other way, you might try instrumenting the path that<br>
scans objects and pushes what they reference onto the mark queue to<br>
look for bad values.<br>
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