thread 'main' panicked at 'expected no file state for ../src/preload/preload_interface.h', src/work.rs:575:17

[petr-tik]

Thanks a lot for reviewing so swiftly. I installed the most recent version of n2 and it now gives a similar warning to ninja, however it still fails to build (with a new error this time).

I can create a new issue with the new error, if you want

install most recent n2 (sadly n2 doesn't have a version cli flag to print this easily)

~/Coding/rr $ n2 --version
n2: error: Unrecognized option: 'version'

in the rr directory (checked out at the same commit), clean the build dir and tell cmake to generate build.ninja again.

rm -rf build && mkdir build && cd build && cmake -G Ninja ../ && cd ..
-- The C compiler identification is GNU 7.5.0
-- The CXX compiler identification is GNU 7.5.0
-- The ASM compiler identification is GNU
-- Found assembler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Performing Test SUPPORTS_CXX14
-- Performing Test SUPPORTS_CXX14 - Success
-- Found PkgConfig: /usr/bin/pkg-config (found version "0.29.1") 
-- Checking for module 'capnp'
--   Found capnp, version 0.6.1
-- Checking for module 'zlib'
--   Found zlib, version 1.2.11
-- Found PythonInterp: /usr/bin/python3 (found suitable version "3.6.12", minimum required is "3") 
You have called ADD_LIBRARY for library rrpage without any source files. This typically indicates a problem with your CMakeLists.txt file
You have called ADD_LIBRARY for library rrpreload without any source files. This typically indicates a problem with your CMakeLists.txt file
You have called ADD_LIBRARY for library rraudit without any source files. This typically indicates a problem with your CMakeLists.txt file
You have called ADD_LIBRARY for library rrpage_32 without any source files. This typically indicates a problem with your CMakeLists.txt file
You have called ADD_LIBRARY for library rrpreload_32 without any source files. This typically indicates a problem with your CMakeLists.txt file
You have called ADD_LIBRARY for library rraudit_32 without any source files. This typically indicates a problem with your CMakeLists.txt file
-- Configuring done
-- Generating done
-- Build files have been written to: /home/petr_tik/Coding/rr/build

Fail to build with n2 but this time with warnings and a new error

~/Coding/rr $ RUST_BACKTRACE=full n2 -v -C build/
n2: warn: build.ninja:44074: "../src/preload/preload_interface.h" is repeated in output list
n2: warn: build.ninja:44074: "../src/preload/raw_syscall.S" is repeated in output list
n2: warn: build.ninja:44074: "../src/preload/rrcalls.h" is repeated in output list
thread 'main' panicked at 'expected no file state for ../src/preload/preload_interface.h', src/work.rs:575:17
stack backtrace:
   0:     0x561288ee083a - std::backtrace_rs::backtrace::libunwind::trace::h91c465e73bf6c785
                               at /rustc/9d1b2106e23b1abd32fce1f17267604a5102f57a/library/std/src/../../backtrace/src/backtrace/libunwind.rs:93:5
   1:     0x561288ee083a - std::backtrace_rs::backtrace::trace_unsynchronized::hae9da36f5d58b5f3
                               at /rustc/9d1b2106e23b1abd32fce1f17267604a5102f57a/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x561288ee083a - std::sys_common::backtrace::_print_fmt::h7f499fa126a7effb
                               at /rustc/9d1b2106e23b1abd32fce1f17267604a5102f57a/library/std/src/sys_common/backtrace.rs:67:5
   3:     0x561288ee083a - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h3e2b509ce2ce6007
                               at /rustc/9d1b2106e23b1abd32fce1f17267604a5102f57a/library/std/src/sys_common/backtrace.rs:46:22
   4:     0x561288e8101c - core::fmt::write::h753c7571fa063ecb
                               at /rustc/9d1b2106e23b1abd32fce1f17267604a5102f57a/library/core/src/fmt/mod.rs:1168:17
   5:     0x561288eb6eef - std::io::Write::write_fmt::h2815c0519c99ba09
                               at /rustc/9d1b2106e23b1abd32fce1f17267604a5102f57a/library/std/src/io/mod.rs:1660:15
   6:     0x561288ee18d2 - std::sys_common::backtrace::_print::h64941a6fc8b0ed9b
                               at /rustc/9d1b2106e23b1abd32fce1f17267604a5102f57a/library/std/src/sys_common/backtrace.rs:49:5
   7:     0x561288ee18d2 - std::sys_common::backtrace::print::hcf25e43e1a9b0766
                               at /rustc/9d1b2106e23b1abd32fce1f17267604a5102f57a/library/std/src/sys_common/backtrace.rs:36:9
   8:     0x561288ee18d2 - std::panicking::default_hook::{{closure}}::h78d3e6cf97fc623d
                               at /rustc/9d1b2106e23b1abd32fce1f17267604a5102f57a/library/std/src/panicking.rs:211:50
   9:     0x561288ee26be - std::panicking::default_hook::hda898f8d3ad1a5ae
                               at /rustc/9d1b2106e23b1abd32fce1f17267604a5102f57a/library/std/src/panicking.rs:228:9
  10:     0x561288ee26be - std::panicking::rust_panic_with_hook::h1a5ea2d6c23051aa
                               at /rustc/9d1b2106e23b1abd32fce1f17267604a5102f57a/library/std/src/panicking.rs:606:17
  11:     0x561288ee21a8 - std::panicking::begin_panic_handler::{{closure}}::h07f549390938b73f
                               at /rustc/9d1b2106e23b1abd32fce1f17267604a5102f57a/library/std/src/panicking.rs:502:13
  12:     0x561288ee2126 - std::sys_common::backtrace::__rust_end_short_backtrace::h5ec3758a92cfb00d
                               at /rustc/9d1b2106e23b1abd32fce1f17267604a5102f57a/library/std/src/sys_common/backtrace.rs:139:18
  13:     0x561288ee20e2 - rust_begin_unwind
                               at /rustc/9d1b2106e23b1abd32fce1f17267604a5102f57a/library/std/src/panicking.rs:498:5
  14:     0x561288e79380 - core::panicking::panic_fmt::h3a79a6a99affe1d5
                               at /rustc/9d1b2106e23b1abd32fce1f17267604a5102f57a/library/core/src/panicking.rs:116:14
  15:     0x561288e9b606 - n2::work::Work::check_build_files_missing::hf6446c2d294e5e8f
  16:     0x561288e9b606 - n2::work::Work::check_build_dirty::he52af68592e746be
                               at /home/petr_tik/.cargo/git/checkouts/n2-e6f499fa596a8a82/df0a27b/src/work.rs:590:28
  17:     0x561288e9b606 - n2::work::Work::run_without_cleanup::h19d1906faad45644
                               at /home/petr_tik/.cargo/git/checkouts/n2-e6f499fa596a8a82/df0a27b/src/work.rs:671:21
  18:     0x561288e953d5 - n2::work::Work::run::h249428d76b2080e1
                               at /home/petr_tik/.cargo/git/checkouts/n2-e6f499fa596a8a82/df0a27b/src/work.rs:741:22
  19:     0x561288e953d5 - n2::run::build::{{closure}}::h2daab0ddc1bd4e0c
                               at /home/petr_tik/.cargo/git/checkouts/n2-e6f499fa596a8a82/df0a27b/src/run.rs:49:47
  20:     0x561288e953d5 - n2::trace::scope::h2bf8a771a111bd3b
                               at /home/petr_tik/.cargo/git/checkouts/n2-e6f499fa596a8a82/df0a27b/src/trace.rs:116:21
  21:     0x561288e953d5 - n2::run::build::h6dc9ded841a12ecc
                               at /home/petr_tik/.cargo/git/checkouts/n2-e6f499fa596a8a82/df0a27b/src/run.rs:49:19
  22:     0x561288e91d71 - n2::run::run_impl::h0bb597f9f5680885
                               at /home/petr_tik/.cargo/git/checkouts/n2-e6f499fa596a8a82/df0a27b/src/run.rs:209:22
  23:     0x561288e7e3d0 - n2::run::run::hd21211266b0e6a0b
                               at /home/petr_tik/.cargo/git/checkouts/n2-e6f499fa596a8a82/df0a27b/src/run.rs:234:15
  24:     0x561288e7e3d0 - n2::main::h4c022cd59e4f0615
                               at /home/petr_tik/.cargo/git/checkouts/n2-e6f499fa596a8a82/df0a27b/src/main.rs:4:27
  25:     0x561288e7e6f3 - core::ops::function::FnOnce::call_once::h25e67c454c9b4a24
                               at /rustc/9d1b2106e23b1abd32fce1f17267604a5102f57a/library/core/src/ops/function.rs:227:5
  26:     0x561288e7e6f3 - std::sys_common::backtrace::__rust_begin_short_backtrace::he1b68df33ad7ec41
                               at /rustc/9d1b2106e23b1abd32fce1f17267604a5102f57a/library/std/src/sys_common/backtrace.rs:123:18
  27:     0x561288e7ead9 - main
  28:     0x7f30d8b8cc87 - __libc_start_main
                               at /build/glibc-uZu3wS/glibc-2.27/csu/../csu/libc-start.c:310
  29:     0x561288e7e2da - _start
  30:                0x0 - <unknown>

Start the build with ninja with same warnings!

~/Coding/rr $ ninja -C build/
ninja: Entering directory `build/'
ninja: warning: multiple rules generate ../src/preload/preload_interface.h. builds involving this target will not be correct; continuing anyway [-w dupbuild=warn]
ninja: warning: multiple rules generate ../src/preload/raw_syscall.S. builds involving this target will not be correct; continuing anyway [-w dupbuild=warn]
ninja: warning: multiple rules generate ../src/preload/rrcalls.h. builds involving this target will not be correct; continuing anyway [-w dupbuild=warn]
[1/2405] Linking C executable bin/shared_map_32
[2/2405] Linking C executable bin/strict_priorities_32
[3/2405] Linking C executable bin/segfault_32
ninja: build stopped: interrupted by user.

Originally posted by @petr-tik in #44 (comment)

[philipcraig]

FYI, I have tried to repro this but my build succeeded. I wonder if there is a race condition, as I notice that the file mentioned in the panic preload_interface.h is also one of the files warned about.

[evmar]

Dang, when I "fixed" the previous thing by making it a warning (and not an error), I tried to review the consequences of it and convince myself it would not break anything. But this panic is due to an invariant getting violated. I can just fix it harder, one sec.

[petr-tik]

can confirm that n2 now works! Thanks for addressing so swiftly. Excited to watch this space!