Le mar. 24 sept. 2019 à 00:25, Nicolas Cellier < nicolas.cellier.aka.nice@gmail.com> a écrit :
Follow up: so we have a problem of repeatability... I found nothing like rr for macos, and CPU watchpoint capability is too restricted to be usefull.
So what I did is save a crash.image attempting to crash at resumption time: Smalltalk saveAs: 'crash'. Smalltalk snapshot: true andQuit: true. 5 timesRepeat: [SocketTest suite run].
Then I launched the vm under lldb and gathered $pc stats to see if I could observe some reproducibility (lldb) p/x $pc - methodZoneBase 0x00000000000a0e94 0x0000000000090f70 0x000000000009f824 0x000000000009bfc8 0x000000000009d030 0x000000000009c7c0 0x00000000000951e0 0x00000000000949c8 <- once 0x0000000000094418 0x00000000000949c8 <— twice 0x000000000009b848 0x00000000000a0e94 <- twice 0x000000000009a176 0x000000006dfff2e0 ??? 0x00000000000996d1 0x00000000000949c8 <- thrice good candidate for watchpoint set 0x000000000009ae70 0x000000000009ae70 0x00000000000a18e7 0x0000000000095470 0x000000000009c458 0x00000000000a0a7c 0x0000000000093e89 0x000000000009beb0 0x0000000000095a37 0x0000000000095408 0x00000000000a06bc 0x000000000009cd48 0x0000000000095408 <- twice 0x000000000009ba41 0x0000000000095408 <- thrice new candidate for watchpoint set 0x0000000000045258 <— smallest ever 0x000000000009c7c0 0x0000000000095408 <- fourth ! the watch point was set here, why didn’t it stop??? argh methodZoneBase was incremented after I set the watchpoint!!! 0x00000000000a12dc 0x00000000000951e0 0x00000000000a0e24 0x000000000009ff8c 0x000000000009c7f6 0x000000000009a626
Then I have chosen to watch the most frequent crash address, that is methodZoneBase+0x0000000000095408, Unfortunately, s commented above, I missed one (I set the watchpoint too early, before methodZoneBase took its definitive address).
And after a few (a bunch of) trials, here is what I found:
(lldb) run ../../image/crash.image There is a running process, kill it and restart?: [Y/n] Process 28175 exited with status = 9 (0x00000009) Process 28185 launched: '/Users/nicolas/Smalltalk/OpenSmalltalk/opensmalltalk-vm/build.macos64x64/squeak.cog.spur/Squeak.app/Contents/MacOS/Squeak' (x86_64) Squeak was compiled with optimization - stepping may behave oddly; variables may not be available. Process 28185 stopped
- thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 6.1 frame #0: 0x000000010007bc22 Squeak`-[sqSqueakOSXApplication
doHeadlessSetup](self=0x000000010066fc00, _cmd="doHeadlessSetup") at sqSqueakOSXApplication.m:125 [opt] 122 //No super call here as we've already set headless from command line or info.plist 123 extern BOOL gSqueakHeadless; 124 // Notice that setActivationPolicy: is available in OSX 10.6 and later -> 125 if ([NSApp respondsToSelector:@selector(setActivationPolicy:)]) { 126 if (gSqueakHeadless) { 127 [NSApp setActivationPolicy:NSApplicationActivationPolicyProhibited]; 128 } else { Target 0: (Squeak) stopped. (lldb) wa s e -s 1 -- methodZoneBase+0x0000000000095408 Watchpoint created: Watchpoint 33: addr = 0x107c58138 size = 1 state = enabled type = w new value: -3689348814741910324 (lldb) cont Process 28185 resuming
Watchpoint 33 hit: old value: -3689348814741910324 new value: -3689348814741910836 Process 28185 stopped
- thread #1, queue = 'com.apple.main-thread', stop reason = watchpoint 33 frame #0: 0x00000001000731dc
Squeak`fillInMethodHeadersizeselector(method=0x0000000107c58130, size=544, selector=4435118304) at cogitX64SysV.c:6320 [opt] 6317 sqInt rawHeader; 6318 6319 (method->cmType = CMMethod); -> 6320 (method->objectHeader = nullHeaderForMachineCodeMethod()); 6321 (method->blockSize = size); 6322 (method->methodObject = methodObj); 6323 Target 0: (Squeak) stopped. (lldb) Process 28185 resuming
Watchpoint 33 hit: old value: -3689348814741910836 new value: -3689571654825360894 Process 28185 stopped
- thread #1, queue = 'com.apple.main-thread', stop reason = watchpoint 33 frame #0: 0x0000000100073255
Squeak`fillInMethodHeadersizeselector(method=0x0000000107c58130, size=544, selector=4435118304) at cogitX64SysV.c:6339 [opt] 6336 (method->selector = selector); 6337 (method->cmNumArgs = argumentCountOfMethodHeader(methodHeader)); 6338 (method->cmHasMovableLiteral = hasMovableLiteral); -> 6339 if ((method->cmRefersToYoung = hasYoungReferent)) { 6340 addToYoungReferrers(method); 6341 } 6342 (method->cmUsageCount = initialMethodUsageCount()); Target 0: (Squeak) stopped. (lldb) bt
- thread #1, queue = 'com.apple.main-thread', stop reason = watchpoint 33
- frame #0: 0x0000000100073255
Squeak`fillInMethodHeadersizeselector(method=0x0000000107c58130, size=544, selector=4435118304) at cogitX64SysV.c:6339 [opt] frame #1: 0x000000010004f90c Squeak`compileCogMethod [inlined] generateCogMethod(selector=<unavailable>) at cogitX64SysV.c:7098 [opt] frame #2: 0x000000010004f7a5 Squeak`compileCogMethod(selector=4435118304) at cogitX64SysV.c:27780 [opt] frame #3: 0x000000010004bc54 Squeak`cogselector(aMethodObj=4468481712, aSelectorOop=4435118304) at cogitX64SysV.c:4833 [opt] frame #4: 0x0000000100013d4d Squeak`primitiveClosureValue at gcc3x-cointerp.c:27237 [opt] frame #5: 0x0000000107bd1925 frame #6: 0x000000010000236b Squeak`interpret at gcc3x-cointerp.c:2767 [opt] frame #7: 0x000000010008ed55 Squeak`-[sqSqueakMainApplication runSqueak](self=0x000000010066fc00, _cmd=<unavailable>) at sqSqueakMainApplication.m:201 [opt] frame #8: 0x00007fff44b077b8 Foundation`__NSFirePerformWithOrder + 360 frame #9: 0x00007fff4297cf57 CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__
- 23 frame #10: 0x00007fff4297ce7f CoreFoundation`__CFRunLoopDoObservers +
527 frame #11: 0x00007fff4295f3f8 CoreFoundation`__CFRunLoopRun + 1240 frame #12: 0x00007fff4295ec93 CoreFoundation`CFRunLoopRunSpecific + 483 frame #13: 0x00007fff41c49d96 HIToolbox`RunCurrentEventLoopInMode + 286 frame #14: 0x00007fff41c49a0f HIToolbox`ReceiveNextEventCommon + 366 frame #15: 0x00007fff41c49884 HIToolbox`_BlockUntilNextEventMatchingListInModeWithFilter + 64 frame #16: 0x00007fff3fef9a73 AppKit`_DPSNextEvent + 2085 frame #17: 0x00007fff4068fe34 AppKit`-[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 3044 frame #18: 0x00007fff3feee885 AppKit`-[NSApplication run] + 764 frame #19: 0x00007fff3febda72 AppKit`NSApplicationMain + 804 frame #20: 0x00007fff6a88c015 libdyld.dylib`start + 1 (lldb)
Here I don't know how to proceed, because I have no knowledge of this part of the VM, it's also quite late now... Eliot, does it ring some bell?
Ah, forget it, I thought it was overwriting, but it is the first write on yet virgin methodeZone... (it's just that the scenario was different from all the previous run)
Le dim. 22 sept. 2019 à 11:21, Jan Vrany jan.vrany@fit.cvut.cz a écrit :
On 2019-09-22 10:57, Nicolas Cellier wrote:
Hi Jan, Thanks, a recording debugger would indeed be a tremendous help! Unfortunately, I'm unable to reproduce the bug under linux, only macosx... Do you know something equivalent to rr for mac?
No, I don't. There might be something though, I never had a mac...
Jan
Le dim. 22 sept. 2019 à 09:55, Jan Vrany jan.vrany@fit.cvut.cz a écrit :
Hi,
- can anyone think of any other strategies I might take to try and
reproduce this?
at the risk of stating the obvious, in cases similar to this rr (+ VDB) helped me many times. See https://www.youtube.com/watch?v=Qbu4ED8wPYE
Never used with opensmalltalk VM, though.
HTH, Jan