java -ea -Xmx8000000000 -jar /storage/repos/ultimate/releaseScripts/default/UAutomizer-linux/plugins/org.eclipse.equinox.launcher_1.3.100.v20150511-1540.jar -data @noDefault -ultimatedata /storage/repos/ultimate/releaseScripts/default/UAutomizer-linux/data -tc ../../../trunk/examples/toolchains/C-BIN-BPP-RCFG.xml -s ../../../trunk/examples/settings/default/automizer/svcomp-Reach-32bit-Automizer_Default.epf -i ../../../trunk/examples/svcomp/heap-manipulation/merge_sort_false-unreach-call_false-valid-memcleanup.i -------------------------------------------------------------------------------- This is Ultimate 0.1.23-4ad093a [2018-11-25 20:17:56,266 INFO L170 SettingsManager]: Resetting all preferences to default values... [2018-11-25 20:17:56,269 INFO L174 SettingsManager]: Resetting UltimateCore preferences to default values [2018-11-25 20:17:56,287 INFO L177 SettingsManager]: Ultimate Commandline Interface provides no preferences, ignoring... [2018-11-25 20:17:56,287 INFO L174 SettingsManager]: Resetting Boogie Preprocessor preferences to default values [2018-11-25 20:17:56,289 INFO L174 SettingsManager]: Resetting Boogie Procedure Inliner preferences to default values [2018-11-25 20:17:56,291 INFO L174 SettingsManager]: Resetting Abstract Interpretation preferences to default values [2018-11-25 20:17:56,294 INFO L174 SettingsManager]: Resetting LassoRanker preferences to default values [2018-11-25 20:17:56,297 INFO L174 SettingsManager]: Resetting Reaching Definitions preferences to default values [2018-11-25 20:17:56,298 INFO L174 SettingsManager]: Resetting SyntaxChecker preferences to default values [2018-11-25 20:17:56,300 INFO L177 SettingsManager]: Büchi Program Product provides no preferences, ignoring... [2018-11-25 20:17:56,301 INFO L174 SettingsManager]: Resetting LTL2Aut preferences to default values [2018-11-25 20:17:56,302 INFO L174 SettingsManager]: Resetting PEA to Boogie preferences to default values [2018-11-25 20:17:56,303 INFO L174 SettingsManager]: Resetting BlockEncodingV2 preferences to default values [2018-11-25 20:17:56,309 INFO L174 SettingsManager]: Resetting ChcToBoogie preferences to default values [2018-11-25 20:17:56,310 INFO L174 SettingsManager]: Resetting AutomataScriptInterpreter preferences to default values [2018-11-25 20:17:56,314 INFO L174 SettingsManager]: Resetting BuchiAutomizer preferences to default values [2018-11-25 20:17:56,316 INFO L174 SettingsManager]: Resetting CACSL2BoogieTranslator preferences to default values [2018-11-25 20:17:56,323 INFO L174 SettingsManager]: Resetting CodeCheck preferences to default values [2018-11-25 20:17:56,324 INFO L174 SettingsManager]: Resetting InvariantSynthesis preferences to default values [2018-11-25 20:17:56,327 INFO L174 SettingsManager]: Resetting RCFGBuilder preferences to default values [2018-11-25 20:17:56,329 INFO L174 SettingsManager]: Resetting TraceAbstraction preferences to default values [2018-11-25 20:17:56,335 INFO L177 SettingsManager]: TraceAbstractionConcurrent provides no preferences, ignoring... [2018-11-25 20:17:56,335 INFO L177 SettingsManager]: TraceAbstractionWithAFAs provides no preferences, ignoring... [2018-11-25 20:17:56,335 INFO L174 SettingsManager]: Resetting TreeAutomizer preferences to default values [2018-11-25 20:17:56,336 INFO L174 SettingsManager]: Resetting IcfgTransformer preferences to default values [2018-11-25 20:17:56,337 INFO L174 SettingsManager]: Resetting Boogie Printer preferences to default values [2018-11-25 20:17:56,340 INFO L174 SettingsManager]: Resetting ReqPrinter preferences to default values [2018-11-25 20:17:56,341 INFO L174 SettingsManager]: Resetting Witness Printer preferences to default values [2018-11-25 20:17:56,343 INFO L177 SettingsManager]: Boogie PL CUP Parser provides no preferences, ignoring... [2018-11-25 20:17:56,343 INFO L174 SettingsManager]: Resetting CDTParser preferences to default values [2018-11-25 20:17:56,344 INFO L177 SettingsManager]: AutomataScriptParser provides no preferences, ignoring... [2018-11-25 20:17:56,345 INFO L177 SettingsManager]: ReqParser provides no preferences, ignoring... [2018-11-25 20:17:56,345 INFO L174 SettingsManager]: Resetting SmtParser preferences to default values [2018-11-25 20:17:56,348 INFO L174 SettingsManager]: Resetting Witness Parser preferences to default values [2018-11-25 20:17:56,349 INFO L181 SettingsManager]: Finished resetting all preferences to default values... [2018-11-25 20:17:56,349 INFO L98 SettingsManager]: Beginning loading settings from /storage/repos/ultimate/releaseScripts/default/UAutomizer-linux/../../../trunk/examples/settings/default/automizer/svcomp-Reach-32bit-Automizer_Default.epf [2018-11-25 20:17:56,374 INFO L110 SettingsManager]: Loading preferences was successful [2018-11-25 20:17:56,374 INFO L112 SettingsManager]: Preferences different from defaults after loading the file: [2018-11-25 20:17:56,375 INFO L131 SettingsManager]: Preferences of Boogie Procedure Inliner differ from their defaults: [2018-11-25 20:17:56,375 INFO L133 SettingsManager]: * ... calls to implemented procedures=ONLY_FOR_CONCURRENT_PROGRAMS [2018-11-25 20:17:56,376 INFO L131 SettingsManager]: Preferences of BlockEncodingV2 differ from their defaults: [2018-11-25 20:17:56,376 INFO L133 SettingsManager]: * Create parallel compositions if possible=false [2018-11-25 20:17:56,376 INFO L133 SettingsManager]: * Use SBE=true [2018-11-25 20:17:56,377 INFO L131 SettingsManager]: Preferences of CACSL2BoogieTranslator differ from their defaults: [2018-11-25 20:17:56,377 INFO L133 SettingsManager]: * sizeof long=4 [2018-11-25 20:17:56,377 INFO L133 SettingsManager]: * Overapproximate operations on floating types=true [2018-11-25 20:17:56,377 INFO L133 SettingsManager]: * sizeof POINTER=4 [2018-11-25 20:17:56,377 INFO L133 SettingsManager]: * Check division by zero=IGNORE [2018-11-25 20:17:56,378 INFO L133 SettingsManager]: * Pointer to allocated memory at dereference=IGNORE [2018-11-25 20:17:56,378 INFO L133 SettingsManager]: * If two pointers are subtracted or compared they have the same base address=IGNORE [2018-11-25 20:17:56,378 INFO L133 SettingsManager]: * Check array bounds for arrays that are off heap=IGNORE [2018-11-25 20:17:56,378 INFO L133 SettingsManager]: * sizeof long double=12 [2018-11-25 20:17:56,378 INFO L133 SettingsManager]: * Check if freed pointer was valid=false [2018-11-25 20:17:56,378 INFO L133 SettingsManager]: * Use constant arrays=true [2018-11-25 20:17:56,379 INFO L133 SettingsManager]: * Pointer base address is valid at dereference=IGNORE [2018-11-25 20:17:56,379 INFO L131 SettingsManager]: Preferences of RCFGBuilder differ from their defaults: [2018-11-25 20:17:56,379 INFO L133 SettingsManager]: * Size of a code block=SequenceOfStatements [2018-11-25 20:17:56,379 INFO L133 SettingsManager]: * To the following directory=./dump/ [2018-11-25 20:17:56,380 INFO L133 SettingsManager]: * SMT solver=External_DefaultMode [2018-11-25 20:17:56,380 INFO L133 SettingsManager]: * Command for external solver=z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:2000 [2018-11-25 20:17:56,380 INFO L131 SettingsManager]: Preferences of TraceAbstraction differ from their defaults: [2018-11-25 20:17:56,380 INFO L133 SettingsManager]: * Compute Interpolants along a Counterexample=FPandBP [2018-11-25 20:17:56,380 INFO L133 SettingsManager]: * Positions where we compute the Hoare Annotation=LoopsAndPotentialCycles [2018-11-25 20:17:56,381 INFO L133 SettingsManager]: * Trace refinement strategy=CAMEL [2018-11-25 20:17:56,381 INFO L133 SettingsManager]: * SMT solver=External_ModelsAndUnsatCoreMode [2018-11-25 20:17:56,381 INFO L133 SettingsManager]: * Command for external solver=z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in [2018-11-25 20:17:56,381 INFO L133 SettingsManager]: * Compute Hoare Annotation of negated interpolant automaton, abstraction and CFG=true [2018-11-25 20:17:56,432 INFO L81 nceAwareModelManager]: Repository-Root is: /tmp [2018-11-25 20:17:56,448 INFO L258 ainManager$Toolchain]: [Toolchain 1]: Applicable parser(s) successfully (re)initialized [2018-11-25 20:17:56,452 INFO L214 ainManager$Toolchain]: [Toolchain 1]: Toolchain selected. [2018-11-25 20:17:56,454 INFO L271 PluginConnector]: Initializing CDTParser... [2018-11-25 20:17:56,455 INFO L276 PluginConnector]: CDTParser initialized [2018-11-25 20:17:56,455 INFO L418 ainManager$Toolchain]: [Toolchain 1]: Parsing single file: /storage/repos/ultimate/releaseScripts/default/UAutomizer-linux/../../../trunk/examples/svcomp/heap-manipulation/merge_sort_false-unreach-call_false-valid-memcleanup.i [2018-11-25 20:17:56,521 INFO L221 CDTParser]: Created temporary CDT project at /storage/repos/ultimate/releaseScripts/default/UAutomizer-linux/data/af95c7940/289d38b04938421f92ae648430854fd9/FLAGe786173d2 [2018-11-25 20:17:57,083 INFO L307 CDTParser]: Found 1 translation units. [2018-11-25 20:17:57,084 INFO L161 CDTParser]: Scanning /storage/repos/ultimate/trunk/examples/svcomp/heap-manipulation/merge_sort_false-unreach-call_false-valid-memcleanup.i [2018-11-25 20:17:57,105 INFO L355 CDTParser]: About to delete temporary CDT project at /storage/repos/ultimate/releaseScripts/default/UAutomizer-linux/data/af95c7940/289d38b04938421f92ae648430854fd9/FLAGe786173d2 [2018-11-25 20:17:57,368 INFO L363 CDTParser]: Successfully deleted /storage/repos/ultimate/releaseScripts/default/UAutomizer-linux/data/af95c7940/289d38b04938421f92ae648430854fd9 [2018-11-25 20:17:57,378 INFO L296 ainManager$Toolchain]: ####################### [Toolchain 1] ####################### [2018-11-25 20:17:57,379 INFO L131 ToolchainWalker]: Walking toolchain with 4 elements. [2018-11-25 20:17:57,380 INFO L113 PluginConnector]: ------------------------CACSL2BoogieTranslator---------------------------- [2018-11-25 20:17:57,380 INFO L271 PluginConnector]: Initializing CACSL2BoogieTranslator... [2018-11-25 20:17:57,387 INFO L276 PluginConnector]: CACSL2BoogieTranslator initialized [2018-11-25 20:17:57,388 INFO L185 PluginConnector]: Executing the observer ACSLObjectContainerObserver from plugin CACSL2BoogieTranslator for "CDTParser AST 25.11 08:17:57" (1/1) ... [2018-11-25 20:17:57,391 INFO L205 PluginConnector]: Invalid model from CACSL2BoogieTranslator for observer de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator.ACSLObjectContainerObserver@5f6ea74a and model type de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 25.11 08:17:57, skipping insertion in model container [2018-11-25 20:17:57,392 INFO L185 PluginConnector]: Executing the observer CACSL2BoogieTranslatorObserver from plugin CACSL2BoogieTranslator for "CDTParser AST 25.11 08:17:57" (1/1) ... [2018-11-25 20:17:57,402 INFO L145 MainTranslator]: Starting translation in SV-COMP mode [2018-11-25 20:17:57,464 INFO L176 MainTranslator]: Built tables and reachable declarations [2018-11-25 20:17:57,873 INFO L203 PostProcessor]: Analyzing one entry point: main [2018-11-25 20:17:57,892 INFO L191 MainTranslator]: Completed pre-run [2018-11-25 20:17:57,996 INFO L203 PostProcessor]: Analyzing one entry point: main [2018-11-25 20:17:58,152 INFO L195 MainTranslator]: Completed translation [2018-11-25 20:17:58,153 INFO L202 PluginConnector]: Adding new model de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 25.11 08:17:58 WrapperNode [2018-11-25 20:17:58,153 INFO L132 PluginConnector]: ------------------------ END CACSL2BoogieTranslator---------------------------- [2018-11-25 20:17:58,154 INFO L113 PluginConnector]: ------------------------Boogie Procedure Inliner---------------------------- [2018-11-25 20:17:58,154 INFO L271 PluginConnector]: Initializing Boogie Procedure Inliner... [2018-11-25 20:17:58,154 INFO L276 PluginConnector]: Boogie Procedure Inliner initialized [2018-11-25 20:17:58,164 INFO L185 PluginConnector]: Executing the observer TypeChecker from plugin Boogie Procedure Inliner for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 25.11 08:17:58" (1/1) ... [2018-11-25 20:17:58,193 INFO L185 PluginConnector]: Executing the observer Inliner from plugin Boogie Procedure Inliner for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 25.11 08:17:58" (1/1) ... [2018-11-25 20:17:58,205 INFO L132 PluginConnector]: ------------------------ END Boogie Procedure Inliner---------------------------- [2018-11-25 20:17:58,205 INFO L113 PluginConnector]: ------------------------Boogie Preprocessor---------------------------- [2018-11-25 20:17:58,205 INFO L271 PluginConnector]: Initializing Boogie Preprocessor... [2018-11-25 20:17:58,206 INFO L276 PluginConnector]: Boogie Preprocessor initialized [2018-11-25 20:17:58,216 INFO L185 PluginConnector]: Executing the observer EnsureBoogieModelObserver from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 25.11 08:17:58" (1/1) ... [2018-11-25 20:17:58,217 INFO L185 PluginConnector]: Executing the observer TypeChecker from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 25.11 08:17:58" (1/1) ... [2018-11-25 20:17:58,222 INFO L185 PluginConnector]: Executing the observer ConstExpander from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 25.11 08:17:58" (1/1) ... [2018-11-25 20:17:58,223 INFO L185 PluginConnector]: Executing the observer StructExpander from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 25.11 08:17:58" (1/1) ... [2018-11-25 20:17:58,255 INFO L185 PluginConnector]: Executing the observer UnstructureCode from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 25.11 08:17:58" (1/1) ... [2018-11-25 20:17:58,278 INFO L185 PluginConnector]: Executing the observer FunctionInliner from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 25.11 08:17:58" (1/1) ... [2018-11-25 20:17:58,281 INFO L185 PluginConnector]: Executing the observer BoogieSymbolTableConstructor from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 25.11 08:17:58" (1/1) ... [2018-11-25 20:17:58,286 INFO L132 PluginConnector]: ------------------------ END Boogie Preprocessor---------------------------- [2018-11-25 20:17:58,289 INFO L113 PluginConnector]: ------------------------RCFGBuilder---------------------------- [2018-11-25 20:17:58,290 INFO L271 PluginConnector]: Initializing RCFGBuilder... [2018-11-25 20:17:58,290 INFO L276 PluginConnector]: RCFGBuilder initialized [2018-11-25 20:17:58,291 INFO L185 PluginConnector]: Executing the observer RCFGBuilderObserver from plugin RCFGBuilder for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 25.11 08:17:58" (1/1) ... No working directory specified, using /storage/repos/ultimate/releaseScripts/default/UAutomizer-linux/z3 Starting monitored process 1 with z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:2000 (exit command is (exit), workingDir is null) Waiting until toolchain timeout for monitored process 1 with z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:2000 [2018-11-25 20:17:58,344 INFO L130 BoogieDeclarations]: Found specification of procedure inspect_before [2018-11-25 20:17:58,344 INFO L138 BoogieDeclarations]: Found implementation of procedure inspect_before [2018-11-25 20:17:58,344 INFO L130 BoogieDeclarations]: Found specification of procedure inspect_after [2018-11-25 20:17:58,345 INFO L138 BoogieDeclarations]: Found implementation of procedure inspect_after [2018-11-25 20:17:58,345 INFO L130 BoogieDeclarations]: Found specification of procedure #Ultimate.alloc [2018-11-25 20:17:58,345 INFO L130 BoogieDeclarations]: Found specification of procedure read~int [2018-11-25 20:17:58,345 INFO L130 BoogieDeclarations]: Found specification of procedure merge_single_node [2018-11-25 20:17:58,345 INFO L138 BoogieDeclarations]: Found implementation of procedure merge_single_node [2018-11-25 20:17:58,345 INFO L130 BoogieDeclarations]: Found specification of procedure fail [2018-11-25 20:17:58,346 INFO L138 BoogieDeclarations]: Found implementation of procedure fail [2018-11-25 20:17:58,346 INFO L130 BoogieDeclarations]: Found specification of procedure write~int [2018-11-25 20:17:58,347 INFO L130 BoogieDeclarations]: Found specification of procedure ULTIMATE.init [2018-11-25 20:17:58,347 INFO L138 BoogieDeclarations]: Found implementation of procedure ULTIMATE.init [2018-11-25 20:17:58,347 INFO L130 BoogieDeclarations]: Found specification of procedure merge_pair [2018-11-25 20:17:58,347 INFO L138 BoogieDeclarations]: Found implementation of procedure merge_pair [2018-11-25 20:17:58,347 INFO L130 BoogieDeclarations]: Found specification of procedure main [2018-11-25 20:17:58,348 INFO L138 BoogieDeclarations]: Found implementation of procedure main [2018-11-25 20:17:58,348 INFO L130 BoogieDeclarations]: Found specification of procedure write~$Pointer$ [2018-11-25 20:17:58,348 INFO L130 BoogieDeclarations]: Found specification of procedure read~$Pointer$ [2018-11-25 20:17:58,348 INFO L130 BoogieDeclarations]: Found specification of procedure seq_sort_core [2018-11-25 20:17:58,349 INFO L138 BoogieDeclarations]: Found implementation of procedure seq_sort_core [2018-11-25 20:17:58,349 INFO L130 BoogieDeclarations]: Found specification of procedure ULTIMATE.dealloc [2018-11-25 20:17:58,349 INFO L130 BoogieDeclarations]: Found specification of procedure ULTIMATE.start [2018-11-25 20:17:58,349 INFO L138 BoogieDeclarations]: Found implementation of procedure ULTIMATE.start [2018-11-25 20:18:00,312 INFO L275 CfgBuilder]: Using the 1 location(s) as analysis (start of procedure ULTIMATE.start) [2018-11-25 20:18:00,313 INFO L280 CfgBuilder]: Removed 33 assue(true) statements. [2018-11-25 20:18:00,313 INFO L202 PluginConnector]: Adding new model de.uni_freiburg.informatik.ultimate.plugins.generator.rcfgbuilder CFG 25.11 08:18:00 BoogieIcfgContainer [2018-11-25 20:18:00,313 INFO L132 PluginConnector]: ------------------------ END RCFGBuilder---------------------------- [2018-11-25 20:18:00,316 INFO L168 Benchmark]: Toolchain (without parser) took 2937.75 ms. Allocated memory was 1.5 GB in the beginning and 2.2 GB in the end (delta: 707.3 MB). Free memory was 1.4 GB in the beginning and 2.1 GB in the end (delta: -663.8 MB). Peak memory consumption was 43.5 MB. Max. memory is 7.1 GB. [2018-11-25 20:18:00,318 INFO L168 Benchmark]: CDTParser took 0.22 ms. Allocated memory is still 1.5 GB. Free memory is still 1.4 GB. There was no memory consumed. Max. memory is 7.1 GB. [2018-11-25 20:18:00,319 INFO L168 Benchmark]: CACSL2BoogieTranslator took 772.91 ms. Allocated memory was 1.5 GB in the beginning and 2.2 GB in the end (delta: 707.3 MB). Free memory was 1.4 GB in the beginning and 2.2 GB in the end (delta: -768.2 MB). Peak memory consumption was 49.7 MB. Max. memory is 7.1 GB. [2018-11-25 20:18:00,320 INFO L168 Benchmark]: Boogie Procedure Inliner took 51.21 ms. Allocated memory is still 2.2 GB. Free memory was 2.2 GB in the beginning and 2.2 GB in the end (delta: 13.6 MB). Peak memory consumption was 13.6 MB. Max. memory is 7.1 GB. [2018-11-25 20:18:00,321 INFO L168 Benchmark]: Boogie Preprocessor took 83.92 ms. Allocated memory is still 2.2 GB. Free memory was 2.2 GB in the beginning and 2.1 GB in the end (delta: 13.6 MB). Peak memory consumption was 13.6 MB. Max. memory is 7.1 GB. [2018-11-25 20:18:00,322 INFO L168 Benchmark]: RCFGBuilder took 2024.20 ms. Allocated memory is still 2.2 GB. Free memory was 2.1 GB in the beginning and 2.1 GB in the end (delta: 77.1 MB). Peak memory consumption was 77.1 MB. Max. memory is 7.1 GB. [2018-11-25 20:18:00,326 INFO L336 ainManager$Toolchain]: ####################### End [Toolchain 1] ####################### --- Results --- * Results from de.uni_freiburg.informatik.ultimate.core: - GenericResult: Assertions are enabled Assertions are enabled - StatisticsResult: Toolchain Benchmarks Benchmark results are: * CDTParser took 0.22 ms. Allocated memory is still 1.5 GB. Free memory is still 1.4 GB. There was no memory consumed. Max. memory is 7.1 GB. * CACSL2BoogieTranslator took 772.91 ms. Allocated memory was 1.5 GB in the beginning and 2.2 GB in the end (delta: 707.3 MB). Free memory was 1.4 GB in the beginning and 2.2 GB in the end (delta: -768.2 MB). Peak memory consumption was 49.7 MB. Max. memory is 7.1 GB. * Boogie Procedure Inliner took 51.21 ms. Allocated memory is still 2.2 GB. Free memory was 2.2 GB in the beginning and 2.2 GB in the end (delta: 13.6 MB). Peak memory consumption was 13.6 MB. Max. memory is 7.1 GB. * Boogie Preprocessor took 83.92 ms. Allocated memory is still 2.2 GB. Free memory was 2.2 GB in the beginning and 2.1 GB in the end (delta: 13.6 MB). Peak memory consumption was 13.6 MB. Max. memory is 7.1 GB. * RCFGBuilder took 2024.20 ms. Allocated memory is still 2.2 GB. Free memory was 2.1 GB in the beginning and 2.1 GB in the end (delta: 77.1 MB). Peak memory consumption was 77.1 MB. Max. memory is 7.1 GB. RESULT: Ultimate could not prove your program: Toolchain returned no result. Received shutdown request...