[Vm-dev] [squeak-dev] Endless recursion: "String new: -1"
Tobias Pape
Das.Linux at gmx.de
Thu Jul 7 17:27:57 UTC 2016
On 07.07.2016, at 18:44, Eliot Miranda <eliot.miranda at gmail.com> wrote:
> On Thu, Jul 7, 2016 at 5:42 AM, Tobias Pape <Das.Linux at gmx.de> wrote:
>
> Hi all
>
> (cc vm-dev)
> On 07.07.2016, at 14:28, David T. Lewis <lewis at mail.msen.com> wrote:
>
> > I think the problem is in the primitive error code checking. The primitive
> > is failing with #'bad argument' but the fallback code attempts to handle it
> > as #'insufficient object memory'. It then tries to free some memory, fails
> > to correct the problem, and raises a "Space is low" notifier.
> >
>
> I noted that when we moved to Spur initially and I tried to fix tests.
> The AllocationTest failed, and I changed
>
> ec == #'insufficient object memory' ifTrue:
>
> to
> (ec == #'insufficient object memory' or: [ec == #'bad argument']) ifTrue:
>
> in Behavior>>#basicNew:
>
> Maybe that was an error?
>
> @Eliot, why does Spur return #'bad argument' instead of #'insufficient object memory' when
> too much memory is to be allocated?
>
> It doesn't. It answers bad argument for anything other than an integer in the range 0 to 2^32-1 or 0 to 2^64-1.
But logically, it should return #'insufficient object memory' for > 2^64-1.
Your change to return #'bad argument' with Spur broke AllocationTest>>#testOutOfMemorySignal which
worked on pre-Spur Cog and interpreter.
Best regards
-Tobias
PS: the test that predates spur:
testOutOfMemorySignal
"Ensure that OOM is signaled eventually"
| sz |
sz := 512*1024*1024. "work around the 1GB alloc bug"
self should:[(1 to: 2000) collect:[:i| Array new: sz]] raise: OutOfMemory.
"Call me when this test fails, I want your machine"
sz := 1024*1024*1024*1024.
self should:[Array new: sz] raise: OutOfMemory.
The test failed, technically you have to call David lewis now ;)
> I think your commit of topa 10/7/2015 20:41 for Behavior>>basicNew: is wrong, and should be reverted.
>
>
> Best regards
> -Tobias
>
>
> > Dave
> >
> >
> > On Thu, Jul 07, 2016 at 09:23:14AM +0200, Levente Uzonyi wrote:
> >> Someone seems to have trimmed the versions in the changes file. In Squeak
> >> 4.4 Behavior >> #basicNew: had the following body:
> >>
> >> <primitive: 71>
> >> self isVariable ifFalse:
> >> [self error: self printString, ' cannot have variable sized
> >> instances'].
> >> (sizeRequested isInteger and: [sizeRequested >= 0]) ifTrue:
> >> ["arg okay; space must be low."
> >> OutOfMemory signal.
> >> ^ self basicNew: sizeRequested "retry if user proceeds"].
> >> self primitiveFailed
> >>
> >> So, non-integer and negative arguments were primitive failures.
> >>
> >> Levente
> >>
> >>
> >> On Wed, 6 Jul 2016, David T. Lewis wrote:
> >>
> >>> On Wed, Jul 06, 2016 at 06:43:25AM -0700, marcel.taeumel wrote:
> >>>> Hi, there!
> >>>>
> >>>> Is it okay that there is an endless recursion when evaluating "String
> >>>> new: -1"?
> >>>
> >>> No, it is not okay. It should fail with a primitive failure.
> >>>
> >>> Dave
> >>>
> >>>
> >>>>
> >>>> ...
> >>>> ByteString class(Behavior)>>handleFailingFailingBasicNew:
> >>>> ByteString class(Behavior)>>handleFailingBasicNew:
> >>>> ByteString class(Behavior)>>basicNew:
> >>>> ByteString class(Behavior)>>handleFailingFailingBasicNew:
> >>>> ByteString class(Behavior)>>handleFailingBasicNew:
> >>>> ByteString class(Behavior)>>basicNew:
> >>>> ByteString class(Behavior)>>handleFailingFailingBasicNew:
> >>>> ByteString class(Behavior)>>handleFailingBasicNew:
> >>>> ByteString class(Behavior)>>basicNew:
> >>>> ...
> >>>>
> >>>> I would like to have an error signaled instead. Note that the -1 is just
> >>>> an
> >>>> example for a bad computation. The error I get is "Space is low" then. :-)
> >>>>
> >>>>
> >>>> Best,
> >>>> Marcel
> >>>>
> >>>>
> >>>>
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