[closer-devel] an interesting contextl backtrace

[Attila Lendvai]

Pascal,

take a look at this interesting backtrace (i've cut the irrelevant parts)!

this is triggered on sbcl and contextl head, running a threaded
web-server. the request came from baudispider, which has a habit of
bombing the server with parallel requests.

a quick glance at the contextl code suggests that it's a race
condition, because the code seems to protect itself from the
unboundness of the slot...

any thoughts? shall we send it to sbcl-devel instead?

-- 
 attila

Notice the erosion of your (digital) freedom, and do something about it!

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*** At: 2011-12-13T15:35:40.427419+01:00
*** Message:
HANDLE-TOPLEVEL-ERROR :before is now dealing with this error
*** In thread: http worker 1 / serving request 9 /
HANDLE-LEVEL-1-ERROR / HANDLE-TOPLEVEL-ERROR
*** Error of type UNBOUND-SLOT:
The slot CONTEXTL::OLD-SLOT-DEFINITIONS is unbound in the object
#<STANDARD-LAYER-CLASS XHTML-LAYER {1001A92ED3}>.
*** Backtrace:
 18: (SB-PCL::SLOT-UNBOUND-INTERNAL #<STANDARD-LAYER-CLASS XHTML-LAYER
{1001A92ED3}> 19)
 19: (FINALIZE-INHERITANCE #<STANDARD-LAYER-CLASS XHTML-LAYER {1001A92ED3}>)
 20: ((SB-PCL::EMF FINALIZE-INHERITANCE) #<unavailable argument>
#<unavailable argument> #<STANDARD-LAYER-CLASS XHTML-LAYER
{1001A92ED3}>)
 21: (SB-PCL::CPL-OR-NIL #<STANDARD-LAYER-CLASS XHTML-LAYER {1001A92ED3}>)
 22: (SB-PCL::CLASS-APPLICABLE-USING-CLASS-P #<STANDARD-LAYER-CLASS
XHTML-LAYER {1001A92ED3}> #<STANDARD-LAYER-CLASS XHTML-LAYER
{1001A92ED3}>)
 23: ((LABELS SB-PCL::DO-METHODS :IN
SB-PCL::GENERATE-DISCRIMINATION-NET-INTERNAL) (0) (#<LAYERED-METHOD
RENDER-COMPONENT-STUB # NIL # {1008D8B0F3}>) (CLASS
#<STANDARD-LAYER-CLASS XHTML-LAYER {1001A92ED3}>) (#<LAYERED-METHOD
RENDER-COMPONENT-STUB # # # {1008D8AD53}>) ((1 CLASS #)))
 24: ((LABELS SB-PCL::DO-METHODS :IN
SB-PCL::GENERATE-DISCRIMINATION-NET-INTERNAL) (0) (#<LAYERED-METHOD
RENDER-COMPONENT-STUB #1=# # # {1008D8AD53}> #<LAYERED-METHOD
RENDER-COMPONENT-STUB #1# NIL # {1008D8B0F3}>) T NIL ((1 CLASS #)))
 25: ((LABELS SB-PCL::DO-METHODS :IN
SB-PCL::GENERATE-DISCRIMINATION-NET-INTERNAL) (1 0) (#<LAYERED-METHOD
RENDER-COMPONENT-STUB #1=# # # {1008D8AD53}> #<LAYERED-METHOD
RENDER-COMPONENT-STUB #1# NIL # {1008D8B0F3}>) T NIL NIL)
 26: (SB-PCL::DISPATCH-DFUN-COST #<LAYERED-FUNCTION
RENDER-COMPONENT-STUB {10036FEDAB}> 60)
 27: (SB-PCL::USE-DISPATCH-DFUN-P #<LAYERED-FUNCTION
RENDER-COMPONENT-STUB {10036FEDAB}> NIL)
 28: (SB-PCL::MAKE-CHECKING-DFUN #<LAYERED-FUNCTION
RENDER-COMPONENT-STUB {10036FEDAB}> #S(SB-PCL::FAST-METHOD-CALL
:FUNCTION #<CLOSURE # {100DDF059B}> :PV NIL :NEXT-METHOD-CALL NIL
:ARG-INFO (2)) NIL)
 29: (SB-PCL::INITIAL-DFUN #<LAYERED-FUNCTION RENDER-COMPONENT-STUB
{10036FEDAB}> (#<LAYER NIL {100CE8E153}> #<CONTEXT-MENU/WIDGET
:MENU-ITEMS #>))
 30: ((LABELS HU.DWIM.PRESENTATION::WITH-RENDER-STYLE/COMPONENT-BODY
:IN HU.DWIM.PRESENTATION::=LAYERED-FUNCTION-DEFINER-FOR-RENDER-COMPONENT=))