The stack trace only lists goroutines that are not dead/not system goroutines/not the goroutine that is calling the traceback function. (src/runtime/traceback.go) Additionally, I don't think go reclaims any memory from dead goroutines. allgs struct in src/runtime/proc.go file in the go source code holds all the goroutines that have been created during the lifetime of the program and it is all heap allocated. I don't know if the garbage collector reclaims any of these dead goroutines. If it doesn't, which I don't think it does because nothing ever seems to be removed from allgs.
On Monday, 29 April 2019 23:54:54 UTC-7, Justin Israel wrote: > > > > On Tue, Apr 30, 2019 at 6:33 PM vaastav anand <vaastav...@gmail.com > <javascript:>> wrote: > >> I have encountered a SIGBUS with go before but I was hacking inside the >> runtime and using shared mem with mmap. >> >> goroutines are assigned IDs incrementally and each goroutine at bare >> minimum has 2.1KB stack space in go1.11 down from 2.7KB in go1.10 if I >> recall correctly. So, at the very least at that point you could have easily >> burnt through at least 7.5GB of memory. I am not sure what could happen if >> you somehow exceed the amount of memory available. Seems like that is a >> test you could write and see if launching more goroutines than that could >> fit in the size of memory could actually cause a SIGBUS. >> > > The stack trace only listed 282 goroutines, which seems about right > considering the number of clients that are connected. Its about 3 > goroutines per client connection, plus the other stuff in the server. I > think it just indicates that I have turned over a lot of client connections > over time. > > >> >> On Monday, 29 April 2019 23:25:52 UTC-7, Justin Israel wrote: >>> >>> >>> >>> On Tue, Apr 30, 2019 at 6:09 PM vaastav anand <vaastav...@gmail.com> >>> wrote: >>> >>>> Ok, so in the 2nd piece of code you posted, is some request being >>>> pushed onto some OS queue? If so, is it possible that you may be maxing >>>> the >>>> queue out and then pushing something else into it and that could cause a >>>> SIGBUS as well.... This seems super farfetched tho but it is hard to debug >>>> without really knowing what the application might really be doing. >>>> >>> >>> I want to say that I really appreciate you taking the time to try and >>> give me some possible ideas, even though this is a really vague problem. I >>> had only hoped someone had encountered something similar. >>> >>> So that line in the SIGBUS crash is just trying to add a subscription to >>> a message topic callback in the nats client connection: >>> https://godoc.org/github.com/nats-io/go-nats#Conn.Subscribe >>> It's pretty high level logic at my application level. >>> >>> One thing that stood out to me was that in the crash, the goroutine id >>> number was 3538668. I had to double check to confirm that the go runtime >>> just uses an insignificant increasing number. I guess it does indicate that >>> the application turned over > 3 mil goroutines by that point. I'm wondering >>> if this is caused by something in the gnatsd embedded server ( >>> https://github.com/nats-io/gnatsd/tree/master/server) since most the >>> goroutines do come from that, with all the client handling going on. If we >>> are talking about something that is managing very large queues, that would >>> be the one doing so in this application. >>> >>> >>>> >>>> On Monday, 29 April 2019 22:57:40 UTC-7, Justin Israel wrote: >>>>> >>>>> >>>>> >>>>> On Tue, Apr 30, 2019 at 5:43 PM vaastav anand <vaastav...@gmail.com> >>>>> wrote: >>>>> >>>>>> I'd be very surprised if the anonymous goroutine is the reason behind >>>>>> a SIGBUS violation. >>>>>> So, if I remember SIGBUS correctly, it means that you are issuing a >>>>>> read/write to a memory address which is not really addressable or it is >>>>>> misaligned. I think the chances of the address being misaligned are very >>>>>> low.....so it really has to be a non-existent address. >>>>>> It can happen if you have try to access memory outside the region >>>>>> mmaped into your application. >>>>>> If your application has any kind of mmap or shared memory access, I >>>>>> would start there. >>>>>> In any case your best bet is to somehow reproduce the bug >>>>>> consistently and then figure out which memory access is causing the >>>>>> fault. >>>>>> >>>>> >>>>> My application isn't doing anything with mmap or shared memory, and my >>>>> direct and indirect dependencies don't seem to be anything like that >>>>> either. Its limited to pretty much nats.io client, gnatds embedded >>>>> server, and a thrift rpc. >>>>> >>>>> It seems so random that I doubt I could get a reproducible crash. So I >>>>> can really only try testing this on go 1.11 instead to see if any of the >>>>> GC >>>>> work in 1.12 causes this. >>>>> >>>>> >>>>>> >>>>>> >>>>>> On Monday, 29 April 2019 21:59:34 UTC-7, Justin Israel wrote: >>>>>>> >>>>>>> >>>>>>> On Thursday, November 29, 2018 at 6:22:56 PM UTC+13, Justin Israel >>>>>>> wrote: >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> On Thu, Nov 29, 2018 at 6:20 PM Justin Israel <justin...@gmail.com> >>>>>>>> wrote: >>>>>>>> >>>>>>>>> On Thu, Nov 29, 2018 at 5:32 PM Ian Lance Taylor <ia...@golang.org> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>>> On Wed, Nov 28, 2018 at 7:18 PM Justin Israel < >>>>>>>>>> justin...@gmail.com> wrote: >>>>>>>>>> > >>>>>>>>>> > I've got a service that I have been testing quite a lot over >>>>>>>>>> the last few days. Only after I handed it off for some testing to a >>>>>>>>>> colleague, was he able to produce a SIGBUS panic that I had not seen >>>>>>>>>> before: >>>>>>>>>> > >>>>>>>>>> > go 1.11.2 linux/amd64 >>>>>>>>>> > >>>>>>>>>> > The service does set up its own SIGINT/SIGTERM handling via the >>>>>>>>>> typical siginal.Notify approach. The nature of the program is that >>>>>>>>>> it >>>>>>>>>> listens on nats.io message queues, and receives requests to run >>>>>>>>>> tasks as sub-processes. My tests have been running between 40-200 of >>>>>>>>>> these >>>>>>>>>> instances over the course of a few days. But this panic occurred on >>>>>>>>>> a >>>>>>>>>> completely different machine that those I had been testing... >>>>>>>>>> > >>>>>>>>>> > goroutine 1121 [runnable (scan)]: >>>>>>>>>> > fatal error: unexpected signal during runtime execution >>>>>>>>>> > panic during panic >>>>>>>>>> > [signal SIGBUS: bus error code=0x2 addr=0xfa2adc pc=0x451637] >>>>>>>>>> > >>>>>>>>>> > runtime stack: >>>>>>>>>> > runtime.throw(0xcf7fe3, 0x2a) >>>>>>>>>> > /vol/apps/go/1.11.2/src/runtime/panic.go:608 +0x72 >>>>>>>>>> > runtime.sigpanic() >>>>>>>>>> > /vol/apps/go/1.11.2/src/runtime/signal_unix.go:374 >>>>>>>>>> +0x2f2 >>>>>>>>>> > runtime.gentraceback(0xffffffffffffffff, 0xffffffffffffffff, >>>>>>>>>> 0x0, 0xc0004baa80, 0x0, 0x0, 0x64, 0x0, 0x0, 0x0, ...) >>>>>>>>>> > /vol/apps/go/1.11.2/src/runtime/traceback.go:190 +0x377 >>>>>>>>>> > runtime.traceback1(0xffffffffffffffff, 0xffffffffffffffff, 0x0, >>>>>>>>>> 0xc0004baa80, 0x0) >>>>>>>>>> > /vol/apps/go/1.11.2/src/runtime/traceback.go:728 +0xf3 >>>>>>>>>> > runtime.traceback(0xffffffffffffffff, 0xffffffffffffffff, 0x0, >>>>>>>>>> 0xc0004baa80) >>>>>>>>>> > /vol/apps/go/1.11.2/src/runtime/traceback.go:682 +0x52 >>>>>>>>>> > runtime.tracebackothers(0xc00012e780) >>>>>>>>>> > /vol/apps/go/1.11.2/src/runtime/traceback.go:947 +0x187 >>>>>>>>>> > runtime.dopanic_m(0xc00012e780, 0x42dcc2, 0x7f83f6ffc808, 0x1) >>>>>>>>>> > /vol/apps/go/1.11.2/src/runtime/panic.go:805 +0x2aa >>>>>>>>>> > runtime.fatalthrow.func1() >>>>>>>>>> > /vol/apps/go/1.11.2/src/runtime/panic.go:663 +0x5f >>>>>>>>>> > runtime.fatalthrow() >>>>>>>>>> > /vol/apps/go/1.11.2/src/runtime/panic.go:660 +0x57 >>>>>>>>>> > runtime.throw(0xcf7fe3, 0x2a) >>>>>>>>>> > /vol/apps/go/1.11.2/src/runtime/panic.go:608 +0x72 >>>>>>>>>> > runtime.sigpanic() >>>>>>>>>> > /vol/apps/go/1.11.2/src/runtime/signal_unix.go:374 >>>>>>>>>> +0x2f2 >>>>>>>>>> > runtime.gentraceback(0xffffffffffffffff, 0xffffffffffffffff, >>>>>>>>>> 0x0, 0xc0004baa80, 0x0, 0x0, 0x7fffffff, 0x7f83f6ffcd00, 0x0, 0x0, >>>>>>>>>> ...) >>>>>>>>>> > /vol/apps/go/1.11.2/src/runtime/traceback.go:190 +0x377 >>>>>>>>>> > runtime.scanstack(0xc0004baa80, 0xc000031270) >>>>>>>>>> > /vol/apps/go/1.11.2/src/runtime/mgcmark.go:786 +0x15a >>>>>>>>>> > runtime.scang(0xc0004baa80, 0xc000031270) >>>>>>>>>> > /vol/apps/go/1.11.2/src/runtime/proc.go:947 +0x218 >>>>>>>>>> > runtime.markroot.func1() >>>>>>>>>> > /vol/apps/go/1.11.2/src/runtime/mgcmark.go:264 +0x6d >>>>>>>>>> > runtime.markroot(0xc000031270, 0xc000000047) >>>>>>>>>> > /vol/apps/go/1.11.2/src/runtime/mgcmark.go:245 +0x309 >>>>>>>>>> > runtime.gcDrain(0xc000031270, 0x6) >>>>>>>>>> > /vol/apps/go/1.11.2/src/runtime/mgcmark.go:882 +0x117 >>>>>>>>>> > runtime.gcBgMarkWorker.func2() >>>>>>>>>> > /vol/apps/go/1.11.2/src/runtime/mgc.go:1858 +0x13f >>>>>>>>>> > runtime.systemstack(0x7f83f7ffeb90) >>>>>>>>>> > /vol/apps/go/1.11.2/src/runtime/asm_amd64.s:351 +0x66 >>>>>>>>>> > runtime.mstart() >>>>>>>>>> > /vol/apps/go/1.11.2/src/runtime/proc.go:1229 >>>>>>>>>> > >>>>>>>>>> > Much appreciated for any insight. >>>>>>>>>> >>>>>>>>>> Is the problem repeatable? >>>>>>>>>> >>>>>>>>>> It looks like it crashed while tracing back the stack during >>>>>>>>>> garbage >>>>>>>>>> collection, but I don't know why since the panic was evidently >>>>>>>>>> able to >>>>>>>>>> trace back the stack just fine. >>>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> Thanks for the reply. Unfortunately it was rare and never happened >>>>>>>>> in my own testing of thousands of runs of this service. The colleague >>>>>>>>> that >>>>>>>>> saw this crash on one of his workstations was not able to repro it >>>>>>>>> after >>>>>>>>> attempting another run of the workflow. I wasn't really sure how to >>>>>>>>> debug >>>>>>>>> this particular crash since it was in the gc and I have seen a "panic >>>>>>>>> during panic" before. Thought it might jump out at someone. >>>>>>>>> >>>>>>>> >>>>>>>> Oops. I meant that I *haven't* seen a "panic during panic" before >>>>>>>> :-) >>>>>>>> >>>>>>>> >>>>>>>>> >>>>>>>>>> Ian >>>>>>>>>> >>>>>>>>> >>>>>>> >>>>>>> This is a follow up to the issue of seeing a SIGBUS in my >>>>>>> application. While I still don't have a way to reproduce the problem, I >>>>>>> have received reports from my users of another similar SIGBUS: >>>>>>> >>>>>>> unexpected fault address 0x7fdf50 >>>>>>> fatal error: fault >>>>>>> [signal 0xb code=0x2 addr=0x7fdf50 pc=0x7fdf50] >>>>>>> >>>>>>> runtime.throw(0xad7840, 0x5) >>>>>>> /s/go/1.12.1/src/runtime/panic.go:617 +0x72 fp=0xc000f75aa8 >>>>>>> sp=0xc000f75a78 pc=0x444a5e >>>>>>> runtime.sigpanic() >>>>>>> /s/go/1.12.1/src/runtime/sigpanic_unix.go:387 +0x47e >>>>>>> fp=0xc000f75ad8 sp=0xc000f75aa8 pc=0x444a5e >>>>>>> >>>>>>> project.com/project/obj.(*Server).newPushHandler.func1.1.1(0xc0008ea330, >>>>>>> >>>>>>> 0x25, 0x0) >>>>>>> >>>>>>> This is an anonymous inline function closure that was passed to a >>>>>>> nats.io client topic subscription. If I am reading this correctly, >>>>>>> it seems the address to the anonymous function is suddenly invalid? >>>>>>> >>>>>>> ie. >>>>>>> >>>>>>> go func() { >>>>>>> ... >>>>>>> someChan := make(chan bool, 1) >>>>>>> natsConn.Subscribe(topic, func(_ string, typ Type) { >>>>>>> ... >>>>>>> someChan <- true >>>>>>> }) >>>>>>> ... >>>>>>> }() >>>>>>> >>>>>>> Could I be triggering a bug based on this anonymous function closure >>>>>>> in the goroutine? I can try defining things outside the goroutine, >>>>>>> including the function. But honestly without this being a reliable >>>>>>> crash I >>>>>>> would be fumbling in the dark. >>>>>>> >>>>>>> Justin >>>>>>> >>>>>> -- >>>>>> You received this message because you are subscribed to a topic in >>>>>> the Google Groups "golang-nuts" group. >>>>>> To unsubscribe from this topic, visit >>>>>> https://groups.google.com/d/topic/golang-nuts/5tIkzXWCK0k/unsubscribe >>>>>> . >>>>>> To unsubscribe from this group and all its topics, send an email to >>>>>> golan...@googlegroups.com. >>>>>> For more options, visit https://groups.google.com/d/optout. >>>>>> >>>>> -- >>>> You received this message because you are subscribed to a topic in the >>>> Google Groups "golang-nuts" group. >>>> To unsubscribe from this topic, visit >>>> https://groups.google.com/d/topic/golang-nuts/5tIkzXWCK0k/unsubscribe. >>>> To unsubscribe from this group and all its topics, send an email to >>>> golan...@googlegroups.com. >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>> -- >> You received this message because you are subscribed to a topic in the >> Google Groups "golang-nuts" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/golang-nuts/5tIkzXWCK0k/unsubscribe. >> To unsubscribe from this group and all its topics, send an email to >> golan...@googlegroups.com <javascript:>. >> For more options, visit https://groups.google.com/d/optout. >> > - Add to Phrasebook - No word lists for English -> English... - Create a new word list... - Copy -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. 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