October 2019 - Pharo-dev - lists.pharo.org

Re: [Pharo-dev] Easy first issues for Pharo contributors?

by James Foster

Stef, I see that you added executable comments tasks to the âSimple Issues for Beginnersâ project. Thanks! Another idea I had is method category cleanup. While there is some judgment involved in many of the category names, I see several names that are misspellings (starting with 'accessingâ). I donât know if you want to add a task for that as well, or we can just open pull requests. James > On Oct 6, 2019, at 7:11 AM, James Foster <Smalltalk(a)JGFoster.net> wrote: > > All good suggestions. I especially like the executable examples idea since that will demonstrate understanding of the code but still be easy to describe and easy to confirm. Thanks! > >> On Oct 6, 2019, at 3:10 AM, ducasse <stepharo(a)netcourrier.com> wrote: >> >> >> >>> On 6 Oct 2019, at 07:04, James Foster <Smalltalk(a)JGFoster.net> wrote: >>> >>> Hi Pharo developers, >>> >>> I have a few undergraduate students taking OO programming and Iâm using the Pharo MOOC to get started. One of the goals in our CS program is to get students familiar with a development process using Git, so we require contributions to an open source project is a few classes. Iâd like to assign a Pharo contribution and am looking for easy first issues. >> >> Excellent idea! >> >>> Iâll take a look at the issues marked âEasyâ as well as the âSimple Issues for Beginnersâ project, but would welcome additional ones. >> >> It would be super cool to add executable examples to number and others. >> >>> My current thought is to go through tests looking for use of #âassert:â that could be changed to #âassert:equals:â. I view this as being an improvement but still quite safe and easy to describe. Most of the work will be setting up the environment and going through the development cycle; I want the actual coding to be minimal (but still useful). >> >> Yes. >> Once back in 2005 I gave as exercise to write tests for collections (because they were none back then) after I reviewed revise them and committed them. >> So looking at coverage of classes may be a nice option too. >> >> I think that what you can also ask them is to >> - reproduce issue >> - comment issue >> This is an important aspect too. >> >> Stef >>> >>> James Foster >> >> >> >> > > >

Oct. 11, 2019

[Pharo 8.0] Build #856: FAILURE

by ci-pharo-ci-jenkins2＠inria.fr

There is a new Pharo build available! The status of the build #856 was: FAILURE. Could not extract further issue information from commit message: Update stale.yml - do not close issues, just tag the as stale - update the comment Build Url: https://ci.inria.fr/pharo-ci-jenkins2/job/Test%20pending%20pull%20request%2…

Oct. 10, 2019

Re: [Pharo-dev] PhD starting in January/February 2020 on Advanced debugging with Pharo

by ducasse

JB I think that this blog post is not yours. And this is not even ours. It is available. We just listed it here because it was available. Stef > On 10 Oct 2019, at 14:57, jean baptiste arnaud <jbaptiste.arnaud(a)gmail.com> wrote: > > It is really nice to put me as reference here, even if it is without my consent. Whatever I will embrace the charge if someone is interested by conduct a PhD with rmod I will be more than happy to share my experience feedback with them. The good part, they are a lot of them and the bad part, they are some of them. Feel free to contact me. > But please the next time ask me before. > > >

Oct. 10, 2019

Re: [Pharo-dev] PhD starting in January/February 2020 on Advanced debugging with Pharo

by jean baptiste arnaud

It is really nice to put me as reference here, even if it is without my consent. Whatever I will embrace the charge if someone is interested by conduct a PhD with rmod I will be more than happy to share my experience feedback with them. The good part, they are a lot of them and the bad part, they are some of them. Feel free to contact me. But please the next time ask me before. > > >

Oct. 10, 2019

[Pharo 8.0] Build #855: 2808-do-not-run-RBBadMessageRule-for-tests

by ci-pharo-ci-jenkins2＠inria.fr

There is a new Pharo build available! The status of the build #855 was: SUCCESS. The Pull Request #4880 was integrated: "2808-do-not-run-RBBadMessageRule-for-tests" Pull request url: https://github.com/pharo-project/pharo/pull/4880 Issue Url: https://github.com/pharo-project/pharo/issues/2808 Build Url: https://ci.inria.fr/pharo-ci-jenkins2/job/Test%20pending%20pull%20request%2…

Oct. 10, 2019

[Pharo 8.0] Build #854: Integrate-ObservableSlot-as-part-of-VariablesLibrary

by ci-pharo-ci-jenkins2＠inria.fr

There is a new Pharo build available! The status of the build #854 was: FAILURE. The Pull Request #4877 was integrated: "Integrate-ObservableSlot-as-part-of-VariablesLibrary" Pull request url: https://github.com/pharo-project/pharo/pull/4877 Issue Url: https://github.com/pharo-project/pharo/issues/Integrate Build Url: https://ci.inria.fr/pharo-ci-jenkins2/job/Test%20pending%20pull%20request%2…

Oct. 10, 2019

[Pharo 8.0] Build #853: uffi-add-missing-methods

by ci-pharo-ci-jenkins2＠inria.fr

There is a new Pharo build available! The status of the build #853 was: SUCCESS. The Pull Request #4873 was integrated: "uffi-add-missing-methods" Pull request url: https://github.com/pharo-project/pharo/pull/4873 Issue Url: https://github.com/pharo-project/pharo/issues/uffi Build Url: https://ci.inria.fr/pharo-ci-jenkins2/job/Test%20pending%20pull%20request%2…

Oct. 10, 2019

[Pharo 8.0] Build #852: Compiler: Clean dead code

by ci-pharo-ci-jenkins2＠inria.fr

There is a new Pharo build available! The status of the build #852 was: FAILURE. The Pull Request #4870 was integrated: "Compiler: Clean dead code" Pull request url: https://github.com/pharo-project/pharo/pull/4870 Issue Url: https://github.com/pharo-project/pharo/issues/CompilerClean Build Url: https://ci.inria.fr/pharo-ci-jenkins2/job/Test%20pending%20pull%20request%2…

Oct. 10, 2019

[Pharo 8.0] Build #851: Deprecation Rewrites Dr Tests

by ci-pharo-ci-jenkins2＠inria.fr

There is a new Pharo build available! The status of the build #851 was: FAILURE. The Pull Request #4871 was integrated: "Deprecation Rewrites Dr Tests" Pull request url: https://github.com/pharo-project/pharo/pull/4871 Issue Url: https://github.com/pharo-project/pharo/issues/DeprecationRewrites Build Url: https://ci.inria.fr/pharo-ci-jenkins2/job/Test%20pending%20pull%20request%2…

Oct. 10, 2019

Fixing crashes on delivery of SIGIO etc [Was Re: Seg Fault Pharo 7.0.3, Was Difficult to debug VM crash with full blocks and Sista V1]

by Eliot Miranda

Hi Nicolas, ClÃ©ment, et al, On Tue, Oct 8, 2019 at 1:40 PM Nicolas Cellier < nicolas.cellier.aka.nice(a)gmail.com> wrote: > More on the problem that Eliot is speaking about: it can happen in these > conditions: > if is SIGIO is delivered while executing any trampoline transiting from > SmalltalkToCStackSwitch. > What happens here? > > We must load 64bits contents of memory (cStackPointerAddress) to the stack > pointer register (SPReg = $rsp) - See genLoadCStackPointer. > This is done by using the CogRTLOpcode abstract instruction MoveAwR > But we have no matching instruction in IA-32 X64... We can only load a > 64bits memory content in $rax > So the idea is to generate this sequence > (CogX64Compiler>>concretizeMoveAwR): > xchgq %rsp, %rax > movabsq 0x10027c338, %rax ; cStackPointerAddress > xchgq %rsp, %rax > That's clever because it preserves $rax which could be in use when we want > to MoveAwR. > Clever, but in the case of %rsp and %rbp, dead wrong :blush:. The constraint is that x86_64 only provides a 64-bit load from an absolute address into %rax; no other register can be used. > But it has an unfortunate side effect: the stack pointer temporarily gets > the contents of $rax and can thus temporarily point anywhere. > Right; which is unacceptable. It's a tiny window, but one we hit all the time. > What happens when performing Squeak SocketTest is that we use some > trampolines (I guess for invoking primitives for example) and we generate > SIGIO (for some reasons, there are a lot of SIGIO generated on my > particular macos machine, so I can trigger the bug more easily than Eliot). > We previously installed a handler for SIGIO via signal(). When we use > signal(), the handler shares the stack pointer with user program. > If the event is delivered in between the two xchgq instructions above, the > signal handler will then use a corrupted stack pointer pointing anywhere > (depending no contents of $rax) when the VM enter the signal handler > function, it uses stack pointer to save some states, and corrupt a memory > zone, segfault or whatever. > In the case described by the opensmalltalk vm-dev thread, $rax was > pointing to the generated code zone (jitted methodZone), so we corrupted > the generated code and soon get punished for that. But it's probable that > there might be other (rare) occurrences of this bug. > > Not sure if it is causing the bugs described by Sean, but it's important > to use the fix from Eliot ASAP and retry. > There might be other occurrence of signal(SIGIO,forceInterruptCheck) in > minheadless flavour, I did not check if Eliot also corrected it, if not it > should also be corrected ASAP, as should every usage of signal() be > replaced by ussage of sigaction() with appropriate flags to use > sigaltstack() - see Eliot's commit details. > I want to discuss potential fixes with ClÃ©ment and Nicolas, and anyone else interested. So... 1. the straight forward fix is to generate different code for setting %rsp and %rbp. I shall do this very soon. On x86_64 we dedicate a register for code generation purposes, this is called RISCTempReg, and is either %r8 (SysV ABI (unix)) or %r11 (Windows). RISCTempReg is never assumed to be live except within a single instruction sequence. We can swap with this before assigning to %rsp, e.g. xchgq %r8, %rax movabsq 0x10027c338, %rax ; cStackPointerAddress xchgq %r8, %rax movq %r8, %rsp this adds a couple of bytes, but is reliable. 2. one could imagine exchanging TempReg and RISCTempReg, i.e. TempReg would be either %r8 or %r11, and RISCTemptReg would be %rax. That would allow movabsq 0x10027c338, %rax ; cStackPointerAddress movq %rax, %rsp this at least worked on Ryan's MIPS32 back end when it was in use (no one has tested it in as while AFAIA) where TempReg is S5 (r21), RISCTempReg is AT (r1) and CResultRegister is V0 (r2). So this is worth investigating. [I had tried something similar with HPS and it completely broke the code generator so my gut is trying to tell me this will never work; Ryan has proved otherwise]. 3. I would much rather implement some form of tracking whether a particular register is live or not. A trivial implementation would only track TempReg and only track being not live up until the first assignment to TempReg. A more sophisticated approach could deal with control flow branching and merging of the liveness info. I like the trivial approach for now. That would simply track TempReg and only up until the first explicit assignment to TempReg. 4. we could simply treat assignments to SPReg and FPReg specially, knowing that these are done only in trampolines and enilopmarts (these are the pieces of code that sit b between JITted code and the rest of the run-time (interpreter, memory manager, primitives, etc), either to call the runtime from JITted code or, as in this case, to enter machine code from the run-time. I suppose this is OK as long as we document it. This would allow us to generate what we would generate for #2 above, i.e. movabsq 0x10027c338, %rax ; cStackPointerAddress movq %rax, %rsp N. are there better ways? ClÃ©ment, Nicolas (et al), what do you think? Le dim. 6 oct. 2019 Ã 12:36, Eliot Miranda <eliot.miranda(a)gmail.com> a Ã©crit : > Hi Sean, Hi All, >> >> this may be because of the issue described here: >> http://forum.world.st/Difficult-to-debug-VM-crash-with-full-blocks-and-Sist… >> >> This issue is characterized by the system crashing soon after start up >> when some significant i/o is done, typically either to files or sockets. >> It affects macOS only and may indeed affect only 64-bits. We have strong >> evidence that it is caused by the dynamic linker being invoked in the >> signal handler for SIGIO when the signal is delivered while the VM is >> executing JITted code. The symptom that causes the crash is corruption of >> a particular jitted methodâs machine code, eg Delay class>>#startEventLoop, >> and we believe that the corruption is caused by the linker when it >> misinterprets a jitted Smalltalk stack frame as an ABI-compliant stack >> frame and attempts to scan code to link it. >> >> Our diagnosis is speculative; this is extremely hard to reproduce. >> Typically in repeating a crashing run SIGIO may no longer be delivered at >> the same point because any remote server has now woken up and delivers >> results sooner, etc. However, Nicolas Cellier and I are both confident >> that we have correctly identified the bug. >> >> The fix is simple; SIGIO should be delivered on a dedicated signal stack >> (see sigaltstack(2)). I committed a fix yesterday evening and we should >> see within a week or so if these crashes have disappeared. >> >> I encourage the Pharo vm maintainers to build and release vms that >> include >> https://github.com/OpenSmalltalk/opensmalltalk-vm/commit/c24970eb2859a47406… >> asap. >> >> >> Cheers, >> Eliot >> _,,,^..^,,,_ (phone) >> >> On Oct 3, 2019, at 1:24 PM, Sean P. DeNigris <sean(a)clipperadams.com> >> wrote: >> >> Segmentation fault Thu Oct 3 15:52:33 2019 >> >> >> VM: 201901051900 https://github.com/OpenSmalltalk/opensmalltalk-vm.git >> Date: Sat Jan 5 20:00:11 2019 CommitHash: 7a3c6b6 >> Plugins: 201901051900 >> https://github.com/OpenSmalltalk/opensmalltalk-vm.git >> >> C stack backtrace & registers: >> rax 0x0000000124380000 rbx 0x00007ffeebd00050 rcx 0x0000000000468260 >> rdx >> 0x0000000000dd6800 >> rdi 0x0000000124cee5a0 rsi 0x0000000124cee5a0 rbp 0x00007ffeebcffe50 >> rsp >> 0x00007ffeebcffe50 >> r8 0x00007fff3f2cefe5 r9 0x0000000000000b00 r10 0x0000000000006000 >> r11 >> 0xfffffffffcd8d5a0 >> r12 0x0000000000000002 r13 0x0000000035800000 r14 0x00007ffeebd00064 >> r15 >> 0x0000000000002800 >> rip 0x00007fff630f7d09 >> 0 libsystem_platform.dylib 0x00007fff630f7d09 >> _platform_memmove$VARIANT$Haswell + 41 >> 1 Pharo 0x0000000103f52642 >> reportStackState >> + 952 >> 2 Pharo 0x0000000103f52987 sigsegv + 174 >> 3 libsystem_platform.dylib 0x00007fff630fab3d _sigtramp + 29 >> 4 ??? 0x0000058900000a00 0x0 + >> 6085968660992 >> 5 libGLImage.dylib 0x00007fff3f2ce29e >> glgProcessPixelsWithProcessor + 2149 >> 6 AMDRadeonX5000GLDriver 0x000000010db16db1 >> glrATIStoreLevels >> + 1600 >> 7 AMDRadeonX5000GLDriver 0x000000010db52c83 >> glrAMD_GFX9_LoadSysTextureStandard + 45 >> 8 AMDRadeonX5000GLDriver 0x000000010db519bb >> glrUpdateTexture >> + 1346 >> 9 libGPUSupportMercury.dylib 0x00007fff5181279d >> gpusLoadCurrentTextures + 591 >> 10 AMDRadeonX5000GLDriver 0x000000010db5a099 >> gldUpdateDispatch >> + 397 >> 11 GLEngine 0x00007fff3ff72078 >> gleDoDrawDispatchCore + 629 >> 12 GLEngine 0x00007fff3ff16369 >> glDrawArraysInstanced_STD_Exec + 264 >> 13 GLEngine 0x00007fff3ff1625a >> glDrawArrays_UnpackThread + 40 >> 14 GLEngine 0x00007fff3ff6dce1 >> gleCmdProcessor + >> 77 >> 15 libdispatch.dylib 0x00007fff62ec2dcf >> _dispatch_client_callout + 8 >> 16 libdispatch.dylib 0x00007fff62ecea2c >> _dispatch_lane_barrier_sync_invoke_and_complete + 60 >> 17 GLEngine 0x00007fff3fec4b85 >> glFlush_ExecThread + 15 >> 18 Pharo 0x0000000103f4cc62 >> -[sqSqueakOSXOpenGLView drawRect:flush:] + 314 >> 19 Pharo 0x0000000103f4cb22 - >> ... >> >> Smalltalk stack dump: >> 0x7ffeebd14238 M DelaySemaphoreScheduler>unscheduleAtTimingPriority >> 0x10fab3ad0: a(n) DelaySemaphoreScheduler >> 0x7ffeebd14270 M [] in >> >> DelaySemaphoreScheduler(DelayBasicScheduler)>runBackendLoopAtTimingPriority >> 0x10fab3ad0: a(n) DelaySemaphoreScheduler >> 0x1125923f8 s BlockClosure>ensure: >> 0x111e88d30 s >> >> DelaySemaphoreScheduler(DelayBasicScheduler)>runBackendLoopAtTimingPriority >> 0x112590a50 s [] in >> DelaySemaphoreScheduler(DelayBasicScheduler)>startTimerEventLoopPriority: >> 0x111e88e08 s [] in BlockClosure>newProcess >> >> Most recent primitives >> @ >> actualScreenSize >> millisecondClockValue >> tempAt: >> >> >> >> ----- >> Cheers, >> Sean >> -- >> Sent from: http://forum.world.st/Pharo-Smalltalk-Developers-f1294837.html >> >> -- _,,,^..^,,,_ best, Eliot

Oct. 9, 2019