[Bug 254694] emulators/qemu-user-static: no progress when building lang/rust

Thu Apr 1 13:25:42 UTC 2021

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=254694

            Bug ID: 254694
           Summary: emulators/qemu-user-static: no progress when building
                    lang/rust
           Product: Ports & Packages
           Version: Latest
          Hardware: Any
                OS: Any
            Status: New
          Severity: Affects Only Me
          Priority: ---
         Component: Individual Port(s)
          Assignee: ports-bugs at FreeBSD.org
          Reporter: d8zNeCFG at aon.at
                CC: emulation at FreeBSD.org, rust at FreeBSD.org
                CC: emulation at FreeBSD.org, rust at FreeBSD.org

Created attachment 223747
  --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=223747&action=edit
pstree output when 0% CPU hang occurs

Introduction: In this issue, lang/rust shall be compiled for armv6; the exact
same environment is used both with an emulation provided by qemu-user-static
and natively; when using the emulation the build process eventually hangs with
0% CPU, whereas natively it always proceeds. Emulation is desirable because it
is much faster than the armv6 machine.

Scenario:
- FreeBSD main at 51dfae383bf6298af9e6d816a78b92b6f34d68be (used in all
installations in the following lines, regardless of armv6 or amd64)
- iSCSI-exported disk ("disk925") carrying a complete FreeBSD armv6
installation
- Raspberry Pi B+ ("rpi-b") carrying a complete FreeBSD armv6 installation
(built using "make release")
- bhyve amd64 virtual machine ("v903")
- The goal is to update the armv6 ports using portmaster; amongst them,
lang/rust needs to be built
- Running v903 as a bhyve client under FreeBSD 12.2
- In v903, emulators/qemu-user-static is available, and /etc/rc.conf contains
"qemu_user_static_enable="YES""
- Attaching disk925 in v903; mounting it in /d/925s2a, mounting the special
filesystems underneath (/dev, /dev/fd, /proc, /tmp)
- /usr/ports is NFS-exported from another host and mounted in v903 both in
/net/... and in /d/925s2a/net/... using autofs  (most likely not important to
this issue)
- In v903, issuing "chroot /d/925s2a"
- This opens a qemu-emulated zsh
- Issue "cd /usr/ports/lang/rust"
- Issue "TMPDIR=/usr/tmp make" (the standard TMPDIR=/tmp is too small; most
likely not relevant to this issue)

Result:
- After compiling for an extended period of time progress stops and the qemu
processes just sit there idle.
- It seems that this mostly happens at the linking stage of rust libraries.
- Example: Here is the currently visible output, with 0% CPU load:

   Compiling rustc-main v0.0.0
(/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/rustc-1.51.0-src/compiler/rustc)
     Running
`/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/rustc-1.51.0-src/build/bootstrap/debug/rustc
--crate-name rustc_main --edition=2018 compiler/rustc/src/main.rs
--error-format=json --json=diagnostic-rendered-ansi --crate-type bin
--emit=dep-info,link -C opt-level=3 -C embed-bitcode=no -C debuginfo=0 --cfg
'feature="llvm"' --cfg 'feature="max_level_info"' -C metadata=33c78eec63c05f4e
-C extra-filename=-33c78eec63c05f4e --out-dir
/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/rustc-1.51.0-src/build/armv6-unknown-freebsd/stage1-rustc/armv6-unknown-freebsd/release/deps
--target armv6-unknown-freebsd -C
linker=/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/cc-wrapper -L
dependency=/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/rustc-1.51.0-src/build/armv6-unknown-freebsd/stage1-rustc/armv6-unknown-freebsd/release/deps
-L
dependency=/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/rustc-1.51.0-src/build/armv6-unknown-freebsd/stage1-rustc/release/deps
--extern
rustc_codegen_ssa=/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/rustc-1.51.0-src/build/armv6-unknown-freebsd/stage1-rustc/armv6-unknown-freebsd/release/deps/librustc_codegen_ssa-0891b87bc3d4da8f.rlib
--extern
rustc_driver=/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/rustc-1.51.0-src/build/armv6-unknown-freebsd/stage1-rustc/armv6-unknown-freebsd/release/deps/librustc_driver-623729bd2d57ce51.so
-Zmacro-backtrace '-Clink-args=-Wl,-rpath,$ORIGIN/../lib'
-Ztls-model=initial-exec -Zunstable-options '-Wrustc::internal'
-Cprefer-dynamic -Z binary-dep-depinfo -L
native=/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/rustc-1.51.0-src/build/armv6-unknown-freebsd/stage1-rustc/armv6-unknown-freebsd/release/build/psm-fdd3708a2d632057/out
-L
native=/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/rustc-1.51.0-src/build/armv6-unknown-freebsd/stage1-rustc/armv6-unknown-freebsd/release/build/rustc_llvm-6f28977a172d46d4/out
-L
native=/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/rustc-1.51.0-src/build/armv6-unknown-freebsd/llvm/build/lib`
rustc command:
"LD_LIBRARY_PATH"="/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/rustc-1.51.0-src/build/armv6-unknown-freebsd/stage1/lib:/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/rustc-1.51.0-src/build/armv6-unknown-freebsd/stage1-rustc/release/deps:/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/rustc-1.51.0-src/build/armv6-unknown-freebsd/stage1/lib"
"/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/rustc-1.51.0-src/build/armv6-unknown-freebsd/stage1/bin/rustc"
"--crate-name" "rustc_main" "--edition=2018" "compiler/rustc/src/main.rs"
"--error-format=json" "--json=diagnostic-rendered-ansi" "--crate-type" "bin"
"--emit=dep-info,link" "-C" "opt-level=3" "-C" "embed-bitcode=no" "-C"
"debuginfo=0" "--cfg" "feature=\"llvm\"" "--cfg" "feature=\"max_level_info\""
"-C" "metadata=33c78eec63c05f4e" "-C" "extra-filename=-33c78eec63c05f4e"
"--out-dir"
"/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/rustc-1.51.0-src/build/armv6-unknown-freebsd/stage1-rustc/armv6-unknown-freebsd/release/deps"
"--target" "armv6-unknown-freebsd" "-C"
"linker=/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/cc-wrapper"
"-L"
"dependency=/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/rustc-1.51.0-src/build/armv6-unknown-freebsd/stage1-rustc/armv6-unknown-freebsd/release/deps"
"-L"
"dependency=/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/rustc-1.51.0-src/build/armv6-unknown-freebsd/stage1-rustc/release/deps"
"--extern"
"rustc_codegen_ssa=/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/rustc-1.51.0-src/build/armv6-unknown-freebsd/stage1-rustc/armv6-unknown-freebsd/release/deps/librustc_codegen_ssa-0891b87bc3d4da8f.rlib"
"--extern"
"rustc_driver=/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/rustc-1.51.0-src/build/armv6-unknown-freebsd/stage1-rustc/armv6-unknown-freebsd/release/deps/librustc_driver-623729bd2d57ce51.so"
"-Zmacro-backtrace" "-Clink-args=-Wl,-rpath,$ORIGIN/../lib"
"-Ztls-model=initial-exec" "-Zunstable-options" "-Wrustc::internal"
"-Cprefer-dynamic" "-Z" "binary-dep-depinfo" "-L"
"native=/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/rustc-1.51.0-src/build/armv6-unknown-freebsd/stage1-rustc/armv6-unknown-freebsd/release/build/psm-fdd3708a2d632057/out"
"-L"
"native=/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/rustc-1.51.0-src/build/armv6-unknown-freebsd/stage1-rustc/armv6-unknown-freebsd/release/build/rustc_llvm-6f28977a172d46d4/out"
"-L"
"native=/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/rustc-1.51.0-src/build/armv6-unknown-freebsd/llvm/build/lib"
"-Wrust_2018_idioms" "-Wunused_lifetimes"
"-Wsemicolon_in_expressions_from_macros" "--sysroot"
"/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/rustc-1.51.0-src/build/armv6-unknown-freebsd/stage1"
"-Z" "force-unstable-if-unmarked"
sysroot:
"/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/rustc-1.51.0-src/build/armv6-unknown-freebsd/stage1"
libdir:
"/usr/tmp/net/hal/z/SRC/FreeBSD/ports/head/lang/rust/work/rustc-1.51.0-src/build/armv6-unknown-freebsd/stage1/lib"
    Building [=======================> ] 215/216: rustc-main(bin)

Attached is the associated pstree.

Scenario (continued; the purpose is to continue the compilation on the native
armv6 machine):
- Issue ^C
- Exit the emulated zsh (^D)
- Unmount /d/925s2a etc. from v903
- Detach disk925 from v903
- Attach disk925 in rpi-b
- Mount /d/925s2a as well es /d/925s2a/dev etc. as well as the automounted
directories (/d/925s2a/net; to reach /usr/ports) in rpi-b
- Issue "chroot /d/925s2a" (starts a zsh, this time running natively in exactly
the same environment previously used with qemu-user-static on v903)
- Issue "cd /usr/ports/lang/rust"
- Issue "TMPDIR=/usr/tmp make"

Result (continued):
- The compilation restarts and proceeds alright (albeit much slower than with
the qemu emulation)

Scenario (continued):
- After successfully passing the offending compile (or link?) on the RPI-B+,
again issue ^C, tear down everyting from the RPI-B+, reattach everything again
in the v903 machine, and continue with building the port until the next hang
occurs.

Note:
- This has happened for a very long time and with several updates to
qemu-user-static.

-- Martin

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