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</o:shapelayout></xml><![endif]--></head><body lang=SV link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'>Hi Robert,<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'>Your NIF rtc_upgrade callback function is missing a call to enif_open_resource_type. You can basically do the same call as in rtc_load.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'>The </span><span lang=EN-US style='font-family:"Courier New";mso-fareast-language:EN-US'>upgrade</span><span lang=EN-US style='mso-fareast-language:EN-US'> callback is called when there already exists a loaded instance of the NIF module, which is the case in your second and third calls in the shell to c(rtc).<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'>enif_open_resource_type has to be called (in load or upgrade) for each resource type that is going to be used by that logical NIF module instance. If not, the resource type will be deallocated when all resource objects are gone.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'>/Sverker, Erlang/OTP<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span lang=EN-US>From:</span></b><span lang=EN-US> erlang-questions <erlang-questions-bounces@erlang.org> <b>On Behalf Of </b>Harris, Robert<br><b>Sent:</b> den 26 augusti 2020 21:16<br><b>To:</b> erlang-questions@erlang.org Questions <erlang-questions@erlang.org><br><b>Subject:</b> Help with NIF upgrade implementation<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal style='margin-bottom:12.0pt'>I observe a reproducible SEGV of the 21.3.8.4 VM on macos Catalina when<br>repeatedly recompiling a module that has a skeletal NIF with an upgrade<br>callback. The skeleton is based on the examples in the documentation<br>but I am assuming that I have made an error somewhere. I would be<br>grateful for any pointers.<br><br>The very simple NIF library is attached, together with its makefile and<br>the Erlang module's source. Once built, the failure is seen very<br>quickly:<br><br>$ erl<br>Erlang/OTP 21 [erts-10.3.5.3] [source] [64-bit] [smp:12:12] [ds:12:12:10] [async-threads:1] [hipe]<br><br>Eshell V10.3.5.3 (abort with ^G)<br>1> c(rtc), rtc:foo(), rtc:bar().<br>ok<br>2> c(rtc), rtc:foo(), rtc:bar().<br>ok<br>3> c(rtc), rtc:foo(), rtc:bar().<br>Segmentation fault: 11<br>$<br><br>The stack is<br><br>* thread #10, name = '6_scheduler', stop reason = EXC_BAD_ACCESS (code=1, address=0x70)<br>frame #0: 0x000000001e41bc0e beam.smp`nif_resource_dtor at atomic.h:240<br>237 ETHR_AINT_T__ tmp;<br>238<br>239 tmp = incr;<br>-> 240 __asm__ __volatile__(<br>241 "lock; xadd" ETHR_AINT_SUFFIX__ " %0, %1" /* xadd didn't exist prior to the 486 */<br>242 : "=r"(tmp)<br>243 : "m"(var->counter), "0"(tmp)<br><br>* thread #10, name = '6_scheduler', stop reason = EXC_BAD_ACCESS (code=1, address=0x70)<br>* frame #0: 0x000000001e41bc0e beam.smp`nif_resource_dtor at atomic.h:240<br>frame #1: 0x000000001e41bc07 beam.smp`nif_resource_dtor<br>frame #2: 0x000000001e41bc07 beam.smp`nif_resource_dtor<br>frame #3: 0x000000001e41bc07 beam.smp`nif_resource_dtor<br>frame #4: 0x000000001e41bc07 beam.smp`nif_resource_dtor<br>frame #5: 0x000000001e41bbf0 beam.smp`nif_resource_dtor(bin=0x000000001fc800f8)<br>frame #6: 0x000000001e3d390d beam.smp`sweep_off_heap(p=0x0000000020740778, fullsweep=<unavailable>) at erl_binary.h:453<br>frame #7: 0x000000001e3d73f7 beam.smp`do_minor(p=0x0000000020740778, live_hf_end=<unavailable>, mature=<unavailable>, mature_size=696, new_sz=376, objv=<unavailable>, nobj=3) at erl_gc.c:1674<br>frame #8: 0x000000001e3d9af4 beam.smp`garbage_collect(p=0x0000000020740778, live_hf_end=0xfffffffffffffff8, need=4, objv=0x000000001f7d4440, nobj=3, fcalls=3047, max_young_gen_usage=0) at erl_gc.c:1417<br>frame #9: 0x000000001e3dabb5 beam.smp`erts_garbage_collect_nobump(p=0x0000000020740778, need=<unavailable>, objv=<unavailable>, nobj=<unavailable>, fcalls=3047) at erl_gc.c:878<br>frame #10: 0x000000001e4e8097 beam.smp`process_main(x_reg_array=0x000000001f7d4440, f_reg_array=<unavailable>) at beam_hot.h:104<br>frame #11: 0x000000001e287916 beam.smp`sched_thread_func(vesdp=0x0000000020bb3400) at erl_process.c:8469<br>frame #12: 0x000000001e4cbd52 beam.smp`thr_wrapper(vtwd=0x00007ffee197c140) at ethread.c:118<br>frame #13: 0x00007fff692aa109 libsystem_pthread.dylib`_pthread_start + 148<br>frame #14: 0x00007fff692a5b8b libsystem_pthread.dylib`thread_start + 15<br><br>Robert Harris<br><br>Confidentiality Notice | This email and any included attachments may be privileged, confidential and/or otherwise protected from disclosure. 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