Segfault compiling libc on armv7-unknown-linux-gnueabihf

[fenhl]

Originally reported as rust-lang/libc#1441 but I was asked to report this here.

Steps to reproduce

cargo new --bin compile-fail
cd compile-fail
rustup override set nightly
echo 'libc = "=0.2.60"' >> Cargo.toml
cargo check --release

Output:

     Created binary (application) `compile-fail` package
info: using existing install for 'nightly-armv7-unknown-linux-gnueabihf'
info: override toolchain for '/home/fenhl/compile-fail' set to 'nightly-armv7-unknown-linux-gnueabihf'

  nightly-armv7-unknown-linux-gnueabihf unchanged - rustc 1.38.0-nightly (273f42b59 2019-07-21)

    Updating crates.io index
   Compiling libc v0.2.60
error: Could not compile `libc`.

Caused by:
  process didn't exit successfully: `rustc --crate-name build_script_build /home/fenhl/.cargo/registry/src/github.com-1ecc6299db9ec823/libc-0.2.60/build.rs --color always --crate-type bin --emit=dep-info,link -C opt-level=3 --cfg 'feature="default"' --cfg 'feature="std"' -C metadata=aaad41c440293f27 -C extra-filename=-aaad41c440293f27 --out-dir /home/fenhl/compile-fail/target/release/build/libc-aaad41c440293f27 -L dependency=/home/fenhl/compile-fail/target/release/deps --cap-lints allow` (signal: 11, SIGSEGV: invalid memory reference)

Workaround

Run the cargo check command with RUSTFLAGS='-Ccodegen-units=1' or add the following to the Cargo.toml:

[profile.release]
codegen-units = 1

[gnzlbg]

@jonas-schievink this is also a regression with respect to stable Rust, so we probably need to avoid shipping a beta with this issue.

[mati865]

Can you obtain backtrace using gdb or lldb?

[jonas-schievink]

cc @nikic, this might also be fallout from the LLVM update

[fenhl]

@mati865 is there a guide I can use for this?

[mati865]

@fenhl

$ gdb --args cargo check --release

r (enter)

bt (enter)

q (enter)

and paste the output.

[fenhl]

GNU gdb (Raspbian 8.2.1-2) 8.2.1
Copyright (C) 2018 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Type "show copying" and "show warranty" for details.
This GDB was configured as "arm-linux-gnueabihf".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
    <http://www.gnu.org/software/gdb/documentation/>.

For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from cargo...done.
(gdb) r
Starting program: /home/fenhl/.cargo/bin/cargo check --release
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/arm-linux-gnueabihf/libthread_db.so.1".
process 16341 is executing new program: /home/fenhl/.rustup/toolchains/nightly-armv7-unknown-linux-gnueabihf/bin/cargo
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/arm-linux-gnueabihf/libthread_db.so.1".
[New Thread 0x76d512f0 (LWP 16344)]
   Compiling libc v0.2.60
[New Thread 0x769fe2f0 (LWP 16345)]
[Detaching after fork from child process 16346]                          ] 0/4: libc(build.rs)                                                                                              
[Thread 0x769fe2f0 (LWP 16345) exited]

Thread 2 "cargo" received signal SIGUSR1, User defined signal 1.
[Switching to Thread 0x76d512f0 (LWP 16344)]
futex_wait_cancelable (private=0, expected=0, futex_word=0xe77938) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
88	../sysdeps/unix/sysv/linux/futex-internal.h: No such file or directory.
(gdb) bt
#0  futex_wait_cancelable (private=0, expected=0, futex_word=0xe77938) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0x0, cond=0xe77910) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=0xe77910, mutex=0x0) at pthread_cond_wait.c:655
#3  0x00bd0900 in std::sys::unix::condvar::Condvar::wait () at src/libstd/sys/unix/condvar.rs:69
#4  std::sys_common::condvar::Condvar::wait () at src/libstd/sys_common/condvar.rs:41
#5  std::sync::condvar::Condvar::wait () at src/libstd/sync/condvar.rs:204
#6  std::thread::park () at src/libstd/thread/mod.rs:911
#7  0x00bde4b4 in std::sync::mpsc::blocking::WaitToken::wait () at src/libstd/sync/mpsc/blocking.rs:71
#8  0x00baf508 in std::sync::mpsc::oneshot::Packet<T>::recv ()
#9  0x00baddb8 in std::sync::mpsc::Receiver<T>::recv ()
#10 0x00bb2d38 in std::sys_common::backtrace::__rust_begin_short_backtrace ()
#11 0x00bb1b44 in std::panicking::try::do_call ()
#12 0x00bebf88 in __rust_maybe_catch_panic () at src/libpanic_unwind/lib.rs:82
#13 0x00bb2110 in core::ops::function::FnOnce::call_once{{vtable-shim}} ()
#14 0x00bcfb74 in <alloc::boxed::Box<F> as core::ops::function::FnOnce<A>>::call_once () at /rustc/a7f28678bbf4e16893bb6a718e427504167a9494/src/liballoc/boxed.rs:766
#15 0x00beb48c in <alloc::boxed::Box<F> as core::ops::function::FnOnce<A>>::call_once () at /rustc/a7f28678bbf4e16893bb6a718e427504167a9494/src/liballoc/boxed.rs:766
#16 std::sys_common::thread::start_thread () at src/libstd/sys_common/thread.rs:13
#17 std::sys::unix::thread::Thread::new::thread_start () at src/libstd/sys/unix/thread.rs:79
#18 0x76f56494 in start_thread (arg=0x76d512f0) at pthread_create.c:486
Backtrace stopped: Cannot access memory at address 0x1ec9a
(gdb) q
A debugging session is active.

	Inferior 1 [process 16341] will be killed.

Quit anyway? (y or n) y

[gnzlbg]

cc @nikic - suspicious that this was reported right after the llvm 9 upgrade

[mati865]

@fenhl gdb haven't detected failed thread. Could you try again with this?

$ gdb --args cargo check --release

r (enter)

set pagination off (enter)

thread apply all bt (enter)