From ee6b2e34559aa9915b480794418f1db489d723a8 Mon Sep 17 00:00:00 2001 From: sebres Date: Thu, 29 Aug 2019 20:28:47 +0000 Subject: add test cases covering nested compilation bug [fec0c17d39] (8.5 is not affected at the moment by nested count under 2500) --- tests/compile.test | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) diff --git a/tests/compile.test b/tests/compile.test index 7646c12..c9f1b71 100644 --- a/tests/compile.test +++ b/tests/compile.test @@ -422,6 +422,37 @@ test compile-13.1 {testing underestimate of maxStackSize in list cmd} {exec} { list [catch {exec [interpreter] << $script} msg] $msg } {0 OK} +# Tests of nested compile (body in body compilation), should not generate stack overflow +# (with abnormal program termination), bug [fec0c17d39]: +test compile-13.2 {TclCompileScript: testing nested scripts compilation} -setup { + set i [interp create] + interp recursionlimit $i [expr {10000+50}] + $i eval {proc gencode {nr {cmd eval} {nl 0}} { + set code "" + set e ""; if {$nl} {set e "\n"} + for {set i 0} {$i < $nr} {incr i} { + append code "$cmd \{$e" + } + append code "lappend result 1$e" + for {set i 0} {$i < $nr} {incr i} { + append code "\}$e" + } + #puts [format "%% %.40s ... %d bytes" $code [string length $code]] + return $code + }} +} -body { + # Test different compilation variants (instructions evalStk, invokeStk, etc), + # with 2000 nested scripts (bodies). If you get SO/SF exceptions on some low-stack + # boxes or systems, please don't decrease it (either provide a constraint) + $i eval {foreach cmd {eval "if 1" catch} { + set c [gencode 2000 $cmd] + if 1 $c + }} + $i eval {set result} +} -result {1 1 1} -cleanup { + interp delete $i +} + # Tests compile-14.* for [Bug 599788] [Bug 0c043a175a47da8c2342] test compile-14.1 {testing errors in element name; segfault?} {} { catch {set a([error])} msg1 -- cgit v0.12 From 87e3efddb07fb90ce44be9869ca883a896f1b122 Mon Sep 17 00:00:00 2001 From: sebres Date: Thu, 29 Aug 2019 20:46:46 +0000 Subject: more variants in test (since 8.6 compiles "try" using evalStk instruction) --- tests/compile.test | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tests/compile.test b/tests/compile.test index c651804..ee95d25 100644 --- a/tests/compile.test +++ b/tests/compile.test @@ -488,12 +488,12 @@ test compile-13.2 {TclCompileScript: testing nested scripts compilation} -setup # Test different compilation variants (instructions evalStk, invokeStk, etc), # with 2000 nested scripts (bodies). If you get SO/SF exceptions on some low-stack # boxes or systems, please don't decrease it (either provide a constraint) - $i eval {foreach cmd {eval "if 1" catch} { + $i eval {foreach cmd {eval "if 1" try catch} { set c [gencode 2000 $cmd] if 1 $c }} $i eval {set result} -} -result {1 1 1} -cleanup { +} -result {1 1 1 1} -cleanup { interp delete $i } -- cgit v0.12 From 7efc804258d3dcc195a86386704ed09e7691d9fe Mon Sep 17 00:00:00 2001 From: sebres Date: Thu, 29 Aug 2019 20:50:31 +0000 Subject: closes [fec0c17d39]: fixed stack overflow (followed by SF) by compilation of too many nested bodies (don't use system stack, size of Tcl_Parse is ca. 400 bytes and compiler proc's of commands are reserving stack too) --- generic/tclCompile.c | 47 +++++++++++++++++++++++++++++------------------ 1 file changed, 29 insertions(+), 18 deletions(-) diff --git a/generic/tclCompile.c b/generic/tclCompile.c index 6f90072..87f1bfc 100644 --- a/generic/tclCompile.c +++ b/generic/tclCompile.c @@ -2128,18 +2128,26 @@ TclCompileScript( /* Each iteration compiles one command from the script. */ - while (numBytes > 0) { - Tcl_Parse parse; + if (numBytes > 0) { + /* + * Don't use system stack (size of Tcl_Parse is ca. 400 bytes), so + * many nested compilations (body enclosed in body) can cause abnormal + * program termination with a stack overflow exception, bug [fec0c17d39]. + */ + Tcl_Parse *parsePtr = ckalloc(sizeof(Tcl_Parse)); + + do { const char *next; - if (TCL_OK != Tcl_ParseCommand(interp, p, numBytes, 0, &parse)) { + if (TCL_OK != Tcl_ParseCommand(interp, p, numBytes, 0, parsePtr)) { /* - * Compile bytecodes to report the parse error at runtime. + * Compile bytecodes to report the parsePtr error at runtime. */ - Tcl_LogCommandInfo(interp, script, parse.commandStart, - parse.term + 1 - parse.commandStart); + Tcl_LogCommandInfo(interp, script, parsePtr->commandStart, + parsePtr->term + 1 - parsePtr->commandStart); TclCompileSyntaxError(interp, envPtr); + ckfree(parsePtr); return; } @@ -2150,9 +2158,9 @@ TclCompileScript( */ if ((tclTraceCompile >= 1) && (envPtr->procPtr == NULL)) { - int commandLength = parse.term - parse.commandStart; + int commandLength = parsePtr->term - parsePtr->commandStart; fprintf(stdout, " Compiling: "); - TclPrintSource(stdout, parse.commandStart, + TclPrintSource(stdout, parsePtr->commandStart, TclMin(commandLength, 55)); fprintf(stdout, "\n"); } @@ -2163,48 +2171,51 @@ TclCompileScript( * (See test info-30.33). */ - TclAdvanceLines(&envPtr->line, p, parse.commandStart); + TclAdvanceLines(&envPtr->line, p, parsePtr->commandStart); TclAdvanceContinuations(&envPtr->line, &envPtr->clNext, - parse.commandStart - envPtr->source); + parsePtr->commandStart - envPtr->source); /* * Advance parser to the next command in the script. */ - next = parse.commandStart + parse.commandSize; + next = parsePtr->commandStart + parsePtr->commandSize; numBytes -= next - p; p = next; - if (parse.numWords == 0) { + if (parsePtr->numWords == 0) { /* * The "command" parsed has no words. In this case we can skip * the rest of the loop body. With no words, clearly * CompileCommandTokens() has nothing to do. Since the parser * aggressively sucks up leading comment and white space, - * including newlines, parse.commandStart must be pointing at + * including newlines, parsePtr->commandStart must be pointing at * either the end of script, or a command-terminating semi-colon. * In either case, the TclAdvance*() calls have nothing to do. * Finally, when no words are parsed, no tokens have been - * allocated at parse.tokenPtr so there's also nothing for + * allocated at parsePtr->tokenPtr so there's also nothing for * Tcl_FreeParse() to do. * * The advantage of this shortcut is that CompileCommandTokens() - * can be written with an assumption that parse.numWords > 0, with + * can be written with an assumption that parsePtr->numWords > 0, with * the implication the CCT() always generates bytecode. */ continue; } - lastCmdIdx = CompileCommandTokens(interp, &parse, envPtr); + lastCmdIdx = CompileCommandTokens(interp, parsePtr, envPtr); /* * TIP #280: Track lines in the just compiled command. */ - TclAdvanceLines(&envPtr->line, parse.commandStart, p); + TclAdvanceLines(&envPtr->line, parsePtr->commandStart, p); TclAdvanceContinuations(&envPtr->line, &envPtr->clNext, p - envPtr->source); - Tcl_FreeParse(&parse); + Tcl_FreeParse(parsePtr); + } while (numBytes > 0); + + ckfree(parsePtr); } if (lastCmdIdx == -1) { -- cgit v0.12