<div dir="ltr">It sounds like simulating a terrible (dropping packets) or painfully slow (kbps speeds) network connection might be a more controlled way to reproduce the issue: <a href="https://apple.stackexchange.com/questions/24066/how-to-simulate-slow-internet-connections-on-the-mac">https://apple.stackexchange.com/questions/24066/how-to-simulate-slow-internet-connections-on-the-mac</a></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Sep 13, 2019 at 11:16 PM Eliot Miranda <<a href="mailto:eliot.miranda@gmail.com">eliot.miranda@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> <div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr">Hi All,<br><div><br></div><div> there is a VM bug in 64-bit Spur with the Sista V1 bytecode set and full blocks. The symptom is that when waiting for a remote Monticello repository to update and/or deliver a package version the system crashes in JITTED code after what appears to be some kind of wait.</div><div><br></div><div>This is a reliably occurring bug b ut maddeningly difficult to reproduce. The bug reliably occurs when interacting with a remote rep[ository (e.g. <a href="http://source.squeak.org/VMMaker" target="_blank">http://source.squeak.org/VMMaker</a>) when the server is "cold", and hence makes the image wait. Every time I have tried to repeat the failing sequence the crash has not occurre3d, I think because the server is now "hot" and serves up the version quickly. Today I even tried shutting down my machine for over an hour and rebooting. But I could not get the crash to occur even though it seems to me that every time I try it the first time in the4 day it does crash.</div><div><br></div><div>This is an important bug to fix. If it cannot be fixed then full blocks and Sista V1 are not ready for use in the upcoming Squeak release. I am looking for help in debugging this.</div><div><br></div><div>- is anyone else uising the 64-bit VM with full blocks and Sista V1 who sees hard VM crashes? If so, under what circumstances?</div><div><br></div><div>- is it possible to flush caches in the <a href="http://source.squeak.org/VMMaker" target="_blank">http://source.squeak.org/VMMaker</a> server, or could people tolerate me rebooting the server?</div><div><br></div><div>- is there a way of introducing network delays in Mac OS that might help me induce the bug?</div><div><br></div><div>- can anyone think of any other strategies I might take to try and reproduce this?</div><div><br></div><div>I may have to try and reproduce e the bug in the simulator to have a chance of identifying the bug. Does anyone have a good enough mental model of the Monticello server interaction and have energy to help me figure this one out?</div><div><br></div><div>Here is some information from the last crash I did see in the debugger (alas it is incomplete; there are a number of additional pieces of info I could have collected).</div><div><br></div><div><p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica">(lldb) thr b</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica">* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica"> * frame #0: 0x000000010de5700a</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica"> frame #1: 0x000000010dd7b174</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica"> frame #2: 0x000000010dd45f1c</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica"> frame #3: 0x000000010dd44534</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica"> frame #4: 0x000000010dd44c60</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica">(lldb) x/10i 0x000000010de5700a</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica;min-height:14px"><br></p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica">(lldb) call printStackCallStackOf($rbp)</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica"> 0x7ffeefbdfc30 M Heap>upHeap: 0x11273ca90: a(n) Heap</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica"> 0x7ffeefbdfc68 M Heap>add: 0x11273ca90: a(n) Heap</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica"> 0x7ffeefbdfca0 M Delay class>scheduleDelay:from: 0x1123ebfb8: a(n) Delay class</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica"> 0x7ffeefbdfcf0 M Delay class>handleTimerEvent 0x1123ebfb8: a(n) Delay class</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica"> 0x7ffeefbdfd20 M Delay class>runTimerEventLoop 0x1123ebfb8: a(n) Delay class</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica;min-height:14px"><br></p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica">(lldb) x/10i 0x000000010dd7b174</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica"> 0x10dd7b174: 48 8b 55 10 movq 0x10(%rbp), %rdx</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica"> 0x10dd7b178: 48 89 ec movq %rbp, %rsp</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica"> 0x10dd7b17b: 5d popq %rbp</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica"> 0x10dd7b17c: c2 10 00 retq $0x10</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica"> 0x10dd7b17f: cc int3</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica"> 0x10dd7b180: cc int3</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica"> 0x10dd7b181: cc int3</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica"> 0x10dd7b182: cc int3</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica"> 0x10dd7b183: cc int3</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica"> 0x10dd7b184: cc int3</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica">(lldb) print whereIs(0x000000010dd7b174)</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica">(char *) $0 = 0x00000001000f83ff " is in generated methods"</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica"><span style="font-size:12px">(lldb) call printCogMethodFor((void *)0x000000010dd7b174)</span><br></p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica"> 0x10dd7afc0 <-> 0x10dd7b198: method: 0x112f23c10 selector: 0x112232c20 add:</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica">(lldb) print whereIs(0x000000010de5700a)</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica">(char *) $1 = 0x00000001000f83ff " is in generated methods"</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica">(lldb) call printCogMethodFor((void *)0x000000010de5700a)</p>
<p style="margin:0px;font-stretch:normal;font-size:12px;line-height:normal;font-family:Helvetica"> 0x10de56ba0 <-> 0x10de57078: method: 0x1126ec218 prim 23856 selector: 0x7ffeefbf3d20</p></div><div><br></div><div>this method ends up being the fitted version of Delay class>><span style="font-family:Helvetica;font-size:12px"> startTimerEventLoop</span></div><div dir="ltr" class="gmail-m_7948985732391852149gmail_signature"><div dir="ltr"><div><span style="font-size:small;border-collapse:separate"><div>_,,,^..^,,,_<br></div><div>best, Eliot</div></span></div></div></div></div></div></div></div></div>
</blockquote></div>