Panic under FreeBSD 12 - attempt to subtract with overflow

[AlexanderThaller]

Using master at commit 59929b2d7f5d4e520e6dec03499d71c2460fd866 and using FreeBSD 12.0-RELEASE-p3 FreeBSD 12.0-RELEASE-p3 GENERIC amd64 with rustc 1.36.0-nightly (d35181ad8 2019-05-20)

I get the following error when running cargo test:

# cargo test   
    Finished dev [unoptimized + debuginfo] target(s) in 0.01s
     Running target/debug/deps/systemstat-29c6b1a37a7b0b74

running 10 tests
test platform::tests::test_battery_life ... ok
test platform::tests::test_cpu_measurement_is_send ... ok
test platform::tests::test_memory ... ok
test platform::tests::test_load_average ... ok
test platform::tests::test_mount_at ... FAILED
test platform::tests::test_networks ... ok
test platform::tests::test_on_ac_power ... FAILED
test platform::tests::test_mounts ... FAILED
test platform::tests::test_cpu_load ... ok
test platform::tests::test_cpu_load_aggregate ... ok

failures:

---- platform::tests::test_mount_at stdout ----
thread 'platform::tests::test_mount_at' panicked at 'called `Result::unwrap()` on an `Err` value: Custom { kind: Other, error: StringError("statfs() failed") }', src/libcore/result.rs:999:5
note: Run with `RUST_BACKTRACE=1` environment variable to display a backtrace.

---- platform::tests::test_on_ac_power stdout ----
thread 'platform::tests::test_on_ac_power' panicked at 'called `Result::unwrap()` on an `Err` value: Custom { kind: Other, error: StringError("sysctl() failed") }', src/libcore/result.rs:999:5

---- platform::tests::test_mounts stdout ----
thread 'platform::tests::test_mounts' panicked at 'attempt to subtract with overflow', src/platform/freebsd.rs:220:20


failures:
    platform::tests::test_mount_at
    platform::tests::test_mounts
    platform::tests::test_on_ac_power

test result: FAILED. 7 passed; 3 failed; 0 ignored; 0 measured; 0 filtered out

error: test failed, to rerun pass '--lib'

(I encountered this problem when I tried to run https://github.com/rabite0/hunter).

[AlexanderThaller]

When I add the following debug statements before 220:

impl statfs {
    fn to_fs(&self) -> Filesystem {
        + dbg!(self.f_files as usize);
        + dbg!(self.f_ffree as usize);
        + dbg!(self.f_files as usize - self.f_ffree as usize);

        Filesystem {
            files: self.f_files as usize - self.f_ffree as usize,
            files_total: self.f_files as usize,
            files_avail: self.f_ffree as usize,

I get the following output:

---- platform::tests::test_mounts stdout ----
[src/platform/freebsd.rs:219] self.f_files as usize = 18697390713
[src/platform/freebsd.rs:220] self.f_ffree as usize = 18696449401
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 941312
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 0
[src/platform/freebsd.rs:220] self.f_ffree as usize = 0
[src/platform/freebsd.rs:221] self.f_files as usize - self.f_ffree as usize = 0
[src/platform/freebsd.rs:219] self.f_files as usize = 255
[src/platform/freebsd.rs:220] self.f_ffree as usize = 8421070353367364507
thread 'platform::tests::test_mounts' panicked at 'attempt to subtract with overflow', src/platform/freebsd.rs:221:14

[AlexanderThaller]

I'm running zfs with a fairly large pool so maybe thats an issue:

# zpool list
NAME    SIZE  ALLOC   FREE  CKPOINT  EXPANDSZ   FRAG    CAP  DEDUP  HEALTH  ALTROOT
zroot  36.2T  17.1T  19.1T        -         -     1%    47%  1.00x  ONLINE  -

[AlexanderThaller]

I also tried compiling with rust stable rustc 1.34.2 (6c2484dc3 2019-05-13) but same error.

[valpackett]

hmm which FS is that? could you also dbg print other info, like name/mountpoint?

[malinoskj2]

I just ran into this issue myself. I've got a working patch.