Re: Buildbot failure in Wildebeest Builder on whole buildset

[Arthur Cohen <arthur.cohen@embecosm.com>]

[-- Attachment #1.1.1: Type: text/plain, Size: 9470 bytes --]

Hi everyone,

On 3/2/22 11:05, Thomas Schwinge wrote:
> Hi!
> 
> On 2022-03-02T10:44:38+0100, I wrote:
>> On 2022-03-02T09:03:48+0000, Philip Herron <philip.herron@embecosm.com> wrote:
>>> Yet again the build bots are out doing github automation :D. Would you
>>> be able to give Arthur access to the failing buildbot to test his fix?
>>
>> I suggest as a first step to figure out why your local build aren't
>> running into this issue.  What does running 'build-gcc/gcc/xgcc -v'
>> should for you, and 'grep -i checking build-gcc/gcc/auto-host.h'?
>>
>>> We think we know what the issue is. We changed the lexer so we could
>>> give it a buffer instead of a file for macro expansion, but the string
>>> is going out of scope when we set it up.
>>
>> Ah!  So, "standard C/C++ undefined behavior, memory corruption"...  ;-)
> 
> Indeed.  Building GCC with '--enable-valgrind-annotations' and running
> the GCC self-test through '-wrapper valgrind,--leak-check=full', we see:
> 
>      $ [...]/build-gcc/./gcc/xgcc -B[...]/build-gcc/./gcc/ -xrs -nostdinc /dev/null -S -o /dev/null -fself-test=[...]/source-gcc/gcc/testsuite/selftests -wrapper valgrind,--leak-check=full
>      ==3228208== Memcheck, a memory error detector
>      ==3228208== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
>      ==3228208== Using Valgrind-3.18.1 and LibVEX; rerun with -h for copyright info
>      ==3228208== Command: [...]/build-gcc/./gcc/rust1 /dev/null -quiet -dumpbase null -mtune=generic -march=x86-64 -fself-test=[...]/source-gcc/gcc/testsuite/selftests -o /dev/null -L[...]/build-gcc/./gcc -L/lib/x86_64-linux-gnu -L/lib/../lib64 -L/usr/lib/x86_64-linux-gnu
>      ==3228208==
>      rust1: error: unexpected character ‘1’
>      rust1: error: unexpected character ‘0’
>      rust1: error: unexpected character ‘0’
>      rust1: error: unexpected character ‘0’
>      rust1: error: unexpected character ‘1’
>      rust1: error: unexpected character ‘0’
>      rust1: error: unexpected character ‘0’
>      rust1: error: unexpected character ‘0’
>      ==3228208== Conditional jump or move depends on uninitialised value(s)
>      ==3228208==    at 0x983D5E: Rust::Lexer::build_token() (rust-lex.cc:365)
>      ==3228208==    by 0x987DB4: Rust::buffered_queue<std::shared_ptr<Rust::Token>, Rust::Lexer::TokenSource>::peek(int) (rust-lex.h:233)
>      ==3228208==    by 0x988A46: Rust::parse_cfg_option(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&) (rust-lex.h:166)
>      ==3228208==    by 0x988D83: selftest::rust_cfg_parser_test() (rust-cfg-parser.cc:67)
>      ==3228208==    by 0x96C5EE: selftest::run_rust_tests() (rust-lang.cc:457)
>      ==3228208==    by 0x2527223: selftest::run_tests() (selftest-run-tests.cc:119)
>      ==3228208==    by 0x11C2C29: toplev::run_self_tests() (toplev.cc:2217)
>      ==3228208==    by 0x96991B: toplev::main(int, char**) (toplev.cc:2317)
>      ==3228208==    by 0x96BFD6: main (main.cc:39)
>      [...]
> 
> Before commit 6cf9f8c99c5813a23d7cec473fedf00683f409e4 "Merge #983", that
> was "clean" (just some lost memory etc.).

Thanks a lot for this. I thought it was some memory corruption, 
considering the lexer was seeing garbage characters. I'm a bit 
disappointed my computer and github's CI didn't have the behaviour, but 
oh well.

I'd like to say that this is not my fault and that there really should 
be a wrapper around FILE* operations in the standard C++ library, or 
that this would have been avoided had we been writing Rust, but sadly... :)

I think the patch to test is pretty easy if any of you guys want to test 
it. I'll also send a public key to Mark, thank you for the offer:

---
  gcc/rust/lex/rust-lex.h | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/rust/lex/rust-lex.h b/gcc/rust/lex/rust-lex.h
index c50f63208de..b0d7494f063 100644
--- a/gcc/rust/lex/rust-lex.h
+++ b/gcc/rust/lex/rust-lex.h
@@ -144,7 +144,7 @@ public:
    /**
     * Lex the contents of a string instead of a file
     */
-  static Lexer lex_string (std::string input)
+  static Lexer lex_string (std::string &input)
    {
      // We can perform this ugly cast to a non-const char* since we're only
      // *reading* the string. This would not be valid if we were doing any
-- 
2.35.1

This forces the string to simply be a reference and the caller to make 
sure that it outlives the lexer.
If this passes the valgrind tests, I'll open up a PR with a comment 
explaining the behavior and how we should think about cleaning
it up.

Moral of the story is: fmemopen(3) does not allocate memory in all 
cases, RTFM

>> I can easily test any patches that you need tested.
> 
> 
> Grüße
>   Thomas
> 
> 
>>> On Wed, 2 Mar 2022 at 07:21, Thomas Schwinge <thomas@codesourcery.com> wrote:
>>>>
>>>> Hi!
>>>>
>>>> On 2022-03-02T00:15:41+0100, Mark Wielaard <mark@klomp.org> wrote:
>>>>> On Tue, Mar 01, 2022 at 07:08:15PM +0000, buildbot@builder.wildebeest.org wrote:
>>>>>> The Buildbot has detected a new failure on builder gccrust-debian-arm64 while building gccrust.
>>>>>> Full details are available at:
>>>>>>      https://builder.wildebeest.org/buildbot/#builders/58/builds/1710
>>>>>>
>>>>>> Buildbot URL: https://builder.wildebeest.org/buildbot/
>>>>>>
>>>>>> Worker for this Build: debian-arm64
>>>>>>
>>>>>> Build Reason: <unknown>
>>>>>> Blamelist: Arthur Cohen <arthur.cohen@embecosm.com>
>>>>>>
>>>>>> BUILD FAILED: failed compile (failure)
>>>>>
>>>>> And the same for all other builders.
>>>>
>>>> ... and me: <https://github.com/Rust-GCC/gccrs/issues/987>
>>>> "'[...]/gcc/rust/parse/rust-cfg-parser.cc:67: rust_cfg_parser_test:
>>>> FAIL: ASSERT_TRUE ((Rust::parse_cfg_option (input, key, value)))'".
>>>>
>>>>> I haven't figured out yet why the last commit caused this.
>>>>
>>>> (Same here.)
>>>>
>>>>> But it can be replicated when configuring with --enable-checking=yes
>>>>
>>>> That's strange -- isn't some '--enable-checking=[...]' actually the
>>>> default for GCC builds?
>>>>
>>>>> That causes the selftests to trigger:
>>>>
>>>> At least we can see that the GCC/Rust self-tests are executing!  ;-P
>>>>
>>>>
>>>> Grüße
>>>>   Thomas
>>>>
>>>>
>>>>> make[2]: Entering directory '/home/mark/build/gccrs-obj/gcc'
>>>>> /home/mark/build/gccrs-obj/./gcc/xgcc -B/home/mark/build/gccrs-obj/./gcc/ -xrs -nostdinc /dev/null -S -o /dev/null -fself-test=/home/mark/src/gccrs/gcc/testsuite/selftests
>>>>> rust1: error: unexpected character ‘1’
>>>>> rust1: error: unexpected character ‘0’
>>>>> rust1: error: unexpected character ‘0’
>>>>> rust1: error: unexpected character ‘0’
>>>>> rust1: error: unexpected character ‘1’
>>>>> rust1: error: unexpected character ‘0’
>>>>> rust1: error: unexpected character ‘0’
>>>>> rust1: error: unexpected character ‘0’
>>>>> rust1: error: unexpected character ‘e0’
>>>>> rust1: error: unexpected character ‘d3’
>>>>> rust1: error: unexpected character ‘89’
>>>>> /home/mark/src/gccrs/gcc/rust/parse/rust-cfg-parser.cc:68: rust_cfg_parser_test: FAIL: ASSERT_EQ ((key), ("key_no_value"))
>>>>> rust1: internal compiler error: in fail, at selftest.cc:47
>>>>> 0x1cf096b selftest::fail(selftest::location const&, char const*)
>>>>>        /home/mark/src/gccrs/gcc/selftest.cc:47
>>>>> 0x7bb9a3 selftest::rust_cfg_parser_test()
>>>>>        /home/mark/src/gccrs/gcc/rust/parse/rust-cfg-parser.cc:68
>>>>> 0x1c143b7 selftest::run_tests()
>>>>>        /home/mark/src/gccrs/gcc/selftest-run-tests.cc:119
>>>>> 0xf1310b toplev::run_self_tests()
>>>>>        /home/mark/src/gccrs/gcc/toplev.cc:2217
>>>>> Please submit a full bug report,
>>>>> with preprocessed source if appropriate.
>>>>> Please include the complete backtrace with any bug report.
>>>>> See <https://gcc.gnu.org/bugs/> for instructions.
>>>>> make[2]: *** [/home/mark/src/gccrs/gcc/rust/Make-lang.in:232: s-selftest-rust] Error 1
>>>>> make[2]: Leaving directory '/home/mark/build/gccrs-obj/gcc'
>>>>>
>>>>> Cheers,
>>>>>
>>>>> Mark
>>>>>
>>>>> --
>>>>> Gcc-rust mailing list
>>>>> Gcc-rust@gcc.gnu.org
>>>>> https://gcc.gnu.org/mailman/listinfo/gcc-rust
>>>> -----------------
>>>> Siemens Electronic Design Automation GmbH; Anschrift: Arnulfstraße 201, 80634 München; Gesellschaft mit beschränkter Haftung; Geschäftsführer: Thomas Heurung, Frank Thürauf; Sitz der Gesellschaft: München; Registergericht München, HRB 106955
>>>> --
>>>> Gcc-rust mailing list
>>>> Gcc-rust@gcc.gnu.org
>>>> https://gcc.gnu.org/mailman/listinfo/gcc-rust
> -----------------
> Siemens Electronic Design Automation GmbH; Anschrift: Arnulfstraße 201, 80634 München; Gesellschaft mit beschränkter Haftung; Geschäftsführer: Thomas Heurung, Frank Thürauf; Sitz der Gesellschaft: München; Registergericht München, HRB 106955

Thanks a lot,

-- 
Arthur Cohen <arthur.cohen@embecosm.com>

Toolchain Engineer

Embecosm GmbH

Geschäftsführer: Jeremy Bennett
Niederlassung: Nürnberg
Handelsregister: HR-B 36368
www.embecosm.de

Fürther Str. 27
90429 Nürnberg


Tel.: 091 - 128 707 040
Fax: 091 - 128 707 077

[-- Attachment #1.1.2: OpenPGP public key --]
[-- Type: application/pgp-keys, Size: 3195 bytes --]

[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 840 bytes --]