On non-x86 architectures, test_cpuinfo fails

[musicinmybrain]

Working on a public cloud VM:

$ uname -srvmo
Linux 6.8.0-1018-oracle #19~22.04.1-Ubuntu SMP Mon Dec  9 23:49:53 UTC 2024 aarch64 GNU/Linux
$ git clone https://github.com/eminence/procfs.git
$ cd procfs
$ git checkout v0.17.0
$ RUST_BACKTRACE=1 cargo test
[…]
failures:

---- tests::test_cpuinfo stdout ----
None
thread 'tests::test_cpuinfo' panicked at procfs/src/lib.rs:683:34:
called `Option::unwrap()` on a `None` value
stack backtrace:
   0: rust_begin_unwind
             at /build/rustc-fgzh1o/rustc-1.75.0+dfsg0ubuntu1~bpo0/library/std/src/panicking.rs:645:5
   1: core::panicking::panic_fmt
             at /build/rustc-fgzh1o/rustc-1.75.0+dfsg0ubuntu1~bpo0/library/core/src/panicking.rs:72:14
   2: core::panicking::panic
             at /build/rustc-fgzh1o/rustc-1.75.0+dfsg0ubuntu1~bpo0/library/core/src/panicking.rs:127:5
   3: core::option::Option<T>::unwrap
             at /build/rustc-fgzh1o/rustc-1.75.0+dfsg0ubuntu1~bpo0/library/core/src/option.rs:931:21
   4: procfs::tests::test_cpuinfo
             at ./src/lib.rs:683:13
   5: procfs::tests::test_cpuinfo::{{closure}}
             at ./src/lib.rs:679:22
   6: core::ops::function::FnOnce::call_once
             at /build/rustc-fgzh1o/rustc-1.75.0+dfsg0ubuntu1~bpo0/library/core/src/ops/function.rs:250:5
   7: core::ops::function::FnOnce::call_once
             at /build/rustc-fgzh1o/rustc-1.75.0+dfsg0ubuntu1~bpo0/library/core/src/ops/function.rs:250:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

---- process::task::tests::test_task_runsinglethread stdout ----
thread 'process::task::tests::test_task_runsinglethread' panicked at procfs/src/process/task.rs:202:17:
utime(37) too small
stack backtrace:
   0: rust_begin_unwind
             at /build/rustc-fgzh1o/rustc-1.75.0+dfsg0ubuntu1~bpo0/library/std/src/panicking.rs:645:5
   1: core::panicking::panic_fmt
             at /build/rustc-fgzh1o/rustc-1.75.0+dfsg0ubuntu1~bpo0/library/core/src/panicking.rs:72:14
   2: procfs::process::task::tests::test_task_runsinglethread
             at ./src/process/task.rs:202:17
   3: procfs::process::task::tests::test_task_runsinglethread::{{closure}}
             at ./src/process/task.rs:125:35
   4: core::ops::function::FnOnce::call_once
             at /build/rustc-fgzh1o/rustc-1.75.0+dfsg0ubuntu1~bpo0/library/core/src/ops/function.rs:250:5
   5: core::ops::function::FnOnce::call_once
             at /build/rustc-fgzh1o/rustc-1.75.0+dfsg0ubuntu1~bpo0/library/core/src/ops/function.rs:250:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.


failures:
    process::task::tests::test_task_runsinglethread
    tests::test_cpuinfo

test result: FAILED. 96 passed; 2 failed; 0 ignored; 0 measured; 0 filtered out; finished in 1.09s

I originally saw this while working on an update for the rust-procfs package in Fedora. While the above reproduces it on aarch64, I saw the same test failure on ppc64le and s390x. The test_task_runsinglethread failure is reported separately in #322.

[eminence]

The singlethreaded test failure is probably covered by #322

For the test_cpuinfo failure, can you share your /proc/cpuinfo file?

[musicinmybrain]

The singlethreaded test failure is probably covered by #322

I agree.

For the test_cpuinfo failure, can you share your /proc/cpuinfo file?

Here are typical non-x86 /proc/cpuinfo contents on real hardware in Fedora infrastructure. I confirmed that test_cpuinfo actually failed on each of these.

aarch64

processor	: 0
BogoMIPS	: 50.00
Features	: fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp asimdhp cpuid asimdrdm lrcpc dcpop asimddp
CPU implementer	: 0x41
CPU architecture: 8
CPU variant	: 0x3
CPU part	: 0xd0c
CPU revision	: 1
processor	: 1
BogoMIPS	: 50.00
Features	: fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp asimdhp cpuid asimdrdm lrcpc dcpop asimddp
CPU implementer	: 0x41
CPU architecture: 8
CPU variant	: 0x3
CPU part	: 0xd0c
CPU revision	: 1
processor	: 2
BogoMIPS	: 50.00
Features	: fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp asimdhp cpuid asimdrdm lrcpc dcpop asimddp
CPU implementer	: 0x41
CPU architecture: 8
CPU variant	: 0x3
CPU part	: 0xd0c
CPU revision	: 1
processor	: 3
BogoMIPS	: 50.00
Features	: fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp asimdhp cpuid asimdrdm lrcpc dcpop asimddp
CPU implementer	: 0x41
CPU architecture: 8
CPU variant	: 0x3
CPU part	: 0xd0c
CPU revision	: 1
processor	: 4
BogoMIPS	: 50.00
Features	: fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp asimdhp cpuid asimdrdm lrcpc dcpop asimddp
CPU implementer	: 0x41
CPU architecture: 8
CPU variant	: 0x3
CPU part	: 0xd0c
CPU revision	: 1
processor	: 5
BogoMIPS	: 50.00
Features	: fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp asimdhp cpuid asimdrdm lrcpc dcpop asimddp
CPU implementer	: 0x41
CPU architecture: 8
CPU variant	: 0x3
CPU part	: 0xd0c
CPU revision	: 1
processor	: 6
BogoMIPS	: 50.00
Features	: fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp asimdhp cpuid asimdrdm lrcpc dcpop asimddp
CPU implementer	: 0x41
CPU architecture: 8
CPU variant	: 0x3
CPU part	: 0xd0c
CPU revision	: 1
processor	: 7
BogoMIPS	: 50.00
Features	: fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp asimdhp cpuid asimdrdm lrcpc dcpop asimddp
CPU implementer	: 0x41
CPU architecture: 8
CPU variant	: 0x3
CPU part	: 0xd0c
CPU revision	: 1
processor	: 8
BogoMIPS	: 50.00
Features	: fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp asimdhp cpuid asimdrdm lrcpc dcpop asimddp
CPU implementer	: 0x41
CPU architecture: 8
CPU variant	: 0x3
CPU part	: 0xd0c
CPU revision	: 1
processor	: 9
BogoMIPS	: 50.00
Features	: fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp asimdhp cpuid asimdrdm lrcpc dcpop asimddp
CPU implementer	: 0x41
CPU architecture: 8
CPU variant	: 0x3
CPU part	: 0xd0c
CPU revision	: 1
processor	: 10
BogoMIPS	: 50.00
Features	: fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp asimdhp cpuid asimdrdm lrcpc dcpop asimddp
CPU implementer	: 0x41
CPU architecture: 8
CPU variant	: 0x3
CPU part	: 0xd0c
CPU revision	: 1
processor	: 11
BogoMIPS	: 50.00
Features	: fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp asimdhp cpuid asimdrdm lrcpc dcpop asimddp
CPU implementer	: 0x41
CPU architecture: 8
CPU variant	: 0x3
CPU part	: 0xd0c
CPU revision	: 1

ppc64le

processor	: 0
cpu		: POWER9 (architected), altivec supported
clock		: 2250.000000MHz
revision	: 2.2 (pvr 004e 1202)
processor	: 1
cpu		: POWER9 (architected), altivec supported
clock		: 2250.000000MHz
revision	: 2.2 (pvr 004e 1202)
processor	: 2
cpu		: POWER9 (architected), altivec supported
clock		: 2250.000000MHz
revision	: 2.2 (pvr 004e 1202)
processor	: 3
cpu		: POWER9 (architected), altivec supported
clock		: 2250.000000MHz
revision	: 2.2 (pvr 004e 1202)
processor	: 4
cpu		: POWER9 (architected), altivec supported
clock		: 2250.000000MHz
revision	: 2.2 (pvr 004e 1202)
processor	: 5
cpu		: POWER9 (architected), altivec supported
clock		: 2250.000000MHz
revision	: 2.2 (pvr 004e 1202)
processor	: 6
cpu		: POWER9 (architected), altivec supported
clock		: 2250.000000MHz
revision	: 2.2 (pvr 004e 1202)
processor	: 7
cpu		: POWER9 (architected), altivec supported
clock		: 2250.000000MHz
revision	: 2.2 (pvr 004e 1202)
timebase	: 512000000
platform	: pSeries
model		: IBM pSeries (emulated by qemu)
machine		: CHRP IBM pSeries (emulated by qemu)
MMU		: Radix

Regarding the presence of the string “emulated by qemu,” I know that Fedora uses real PowerPC hardware, so I don’t know why qemu seems to be involved. I could probably find out.

s390x

vendor_id       : IBM/S390
# processors    : 2
bogomips per cpu: 3331.00
max thread id   : 0
features	: esan3 zarch stfle msa ldisp eimm dfp edat etf3eh highgprs te vx vxd vxe gs vxe2 vxp sort dflt vxp2 nnpa sie 
facilities      : 0 1 2 3 4 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 30 31 32 33 34 35 36 37 38 40 41 42 43 44 45 47 48 49 50 51 52 53 54 57 58 59 60 61 64 65 69 71 72 73 74 75 76 77 78 80 81 82 129 130 131 133 134 135 138 139 140 146 147 148 150 151 152 155 156 165 192 193 194 196 197
cache0          : level=1 type=Data scope=Private size=128K line_size=256 associativity=8
cache1          : level=1 type=Instruction scope=Private size=128K line_size=256 associativity=8
cache2          : level=2 type=Unified scope=Private size=32768K line_size=256 associativity=16
cache3          : level=3 type=Unified scope=Shared size=262144K line_size=256 associativity=128
processor 0: version = FF,  identification = 525FA8,  machine = 3931
processor 1: version = FF,  identification = 525FA8,  machine = 3931
cpu number      : 0
physical id     : 0
core id         : 0
book id         : 0
drawer id       : 0
dedicated       : 0
address         : 0
siblings        : 1
cpu cores       : 1
version         : FF
identification  : 525FA8
machine         : 3931
cpu MHz dynamic : 5200
cpu MHz static  : 5200
cpu number      : 1
physical id     : 1
core id         : 1
book id         : 0
drawer id       : 0
dedicated       : 0
address         : 1
siblings        : 1
cpu cores       : 1
version         : FF
identification  : 525FA8
machine         : 3931
cpu MHz dynamic : 5200
cpu MHz static  : 5200

---

The test passes on both x86_64 and i686.