[the8472]

View all comments

The workaround applies on kernels >= 6.9 according to the manpage.
It doesn't work on GHA runners, I suspect virtualization issues, maybe a faulty virtio implementation.
But both on my local machine and on the dev-desktop it works.

running test_append_write_at under strace:

strace: Process 460033 attached
[pid 460033] uname({sysname="Linux", nodename="dev-desktop-eu-1.infra.rust-lang.org", ...}) = 0
[pid 460033] openat(AT_FDCWD, "/tmp/rust-2231989334/file_test_append_write_at.txt", O_WRONLY|O_CREAT|O_TRUNC|O_CLOEXEC, 0666) = 3
[pid 460033] write(3, "it's not working!", 17) = 17
[pid 460033] openat(AT_FDCWD, "/tmp/rust-2231989334/file_test_append_write_at.txt", O_WRONLY|O_APPEND|O_CLOEXEC) = 3
[pid 460033] pwritev2(3, [{iov_base="   ", iov_len=3}], 1, 5, 0x20 /* RWF_??? */) = 3
[pid 460033] openat(AT_FDCWD, "/tmp/rust-2231989334/file_test_append_write_at.txt", O_RDONLY|O_CLOEXEC) = 4
[pid 460033] openat(AT_FDCWD, "/tmp/rust-2231989334", O_RDONLY|O_NOFOLLOW|O_CLOEXEC|O_DIRECTORY) = 3
[pid 460033] +++ exited with 0 +++
[pid 460032] write(1, "{ \"type\": \"test\", \"name\": \"os::u"..., 92) = 92
[pid 460032] write(1, "{ \"type\": \"suite\", \"event\": \"ok\""..., 137) = 137
[pid 459907] write(1, ".", 1.)           = 1
[pid 459907] write(1, "\n", 1
)          = 1
[pid 459907] write(1, "\n", 1
)          = 1
[pid 459907] write(1, "test result: ok. 1 passed; 0 fai"..., 101test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 477 filtered out; finished in 794.28µs

somewhat fixes #140867

[rustbot]

r? @thomcc

rustbot has assigned @thomcc.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

[the8472]

Weird, the kernel should be new enough.

[bors]

☔ The latest upstream changes (presumably #143294) made this pull request unmergeable. Please resolve the merge conflicts.

[the8472]

At this point I'm fairly sure this is a kernel bug in the runner. Tests pass locally, the pwritev2 also happens in CI and doesn't return an error, meaning the flag should be supported.

Filed actions/runner-images#12530

[rustbot]

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

[the8472]

Still broken on ubuntu 26.06. I now suspect something is wrong with GHA, not the ubuntu kernel.

I'll just ignore those tests when detecting an azure kernel.

[the8472]

@rustbot ready

[rust-log-analyzer]

The job test-x86_64-gnu-miri failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

tests/pass/shims/x86/rounding-error.rs ... ok
tests/pass/shims/x86/intrinsics-x86-gfni.rs ... ok

FAILED TEST: tests/pass/shims/fs.rs
command: MIRI_ENV_VAR_TEST="0" MIRI_TEMP="/tmp/miri-uitest-FoIhOm" RUST_BACKTRACE="1" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2-tools/x86_64-unknown-linux-gnu/release/miri" "--error-format=json" "-Dwarnings" "-Dunused" "-Ainternal_features" "-Zui-testing" "--sysroot=/checkout/obj/build/x86_64-unknown-linux-gnu/miri-sysroot" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2-tools/x86_64-unknown-linux-gnu/tmp/miri_ui/0/tests/pass/shims" "tests/pass/shims/fs.rs" "-Zmiri-disable-isolation" "--edition" "2021"

error: test got exit status: 1, but expected 0
 = note: compilation failed, but was expected to succeed

error: actual output differed from expected
Execute `./miri test --bless` to update `tests/pass/shims/fs.stderr` to the actual output
--- tests/pass/shims/fs.stderr
+++ <stderr output>
 hello stderr
+error: unsupported operation: syscall: unsupported syscall number 328
+  --> RUSTLIB/std/src/sys/pal/PLATFORM/weak/syscall.rs:LL:CC
+   |
+LL |                   unsafe { libc::syscall(libc::${concat(SYS_, $name)}, $($param),*) as $ret }
+   |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unsupported operation occurred here
+   |
+  ::: RUSTLIB/std/src/sys/fd/PLATFORM.rs:LL:CC
+   |
+LL | /         syscall!(
+LL | |             fn pwritev2(
+LL | |                 fd: libc::c_int,
+LL | |                 iovec: *const libc::iovec,
+...  |
+LL | |             ) -> isize;
+LL | |         );
+   | |_________- in this macro invocation
+   |
+   = help: this is likely not a bug in the program; it indicates that the program performed an operation that Miri does not support
+   = note: stack backtrace:
+           0: std::sys::fd::PLATFORM::FileDesc::pwritev2::pwritev2
+               at RUSTLIB/std/src/sys/pal/PLATFORM/weak/syscall.rs:LL:CC
+           1: std::sys::fd::PLATFORM::FileDesc::pwritev2
+               at RUSTLIB/std/src/sys/fd/PLATFORM.rs:LL:CC
+           2: std::sys::fd::PLATFORM::FileDesc::write_at
+               at RUSTLIB/std/src/sys/fd/PLATFORM.rs:LL:CC
+           3: std::sys::fs::PLATFORM::File::write_at
+               at RUSTLIB/std/src/sys/fs/PLATFORM.rs:LL:CC
+           4: <std::fs::File as std::os::unix::fs::FileExt>::write_at
+               at RUSTLIB/std/src/os/unix/fs.rs:LL:CC
+           5: <std::fs::File as std::os::unix::fs::FileExt>::write_all_at
---
hello stderr
error: unsupported operation: syscall: unsupported syscall number 328
##[error]  --> /checkout/library/std/src/sys/pal/unix/weak/syscall.rs:15:26
   |
LL |                   unsafe { libc::syscall(libc::${concat(SYS_, $name)}, $($param),*) as $ret }
   |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unsupported operation occurred here
   |
  ::: /checkout/library/std/src/sys/fd/unix.rs:669:9
   |
LL | /         syscall!(
LL | |             fn pwritev2(
LL | |                 fd: libc::c_int,
LL | |                 iovec: *const libc::iovec,
...  |
LL | |             ) -> isize;
LL | |         );
   | |_________- in this macro invocation
   |
   = help: this is likely not a bug in the program; it indicates that the program performed an operation that Miri does not support
   = note: stack backtrace:
           0: std::sys::fd::unix::FileDesc::pwritev2::pwritev2
               at /checkout/library/std/src/sys/pal/unix/weak/syscall.rs:15:26: 15:82
           1: std::sys::fd::unix::FileDesc::pwritev2
               at /checkout/library/std/src/sys/fd/unix.rs:701:21: 707:18
           2: std::sys::fd::unix::FileDesc::write_at
               at /checkout/library/std/src/sys/fd/unix.rs:420:32: 420:59
           3: std::sys::fs::unix::File::write_at
               at /checkout/library/std/src/sys/fs/unix.rs:1517:9: 1517:37
           4: <std::fs::File as std::os::unix::fs::FileExt>::write_at
               at /checkout/library/std/src/os/unix/fs.rs:382:9: 382:46
           5: <std::fs::File as std::os::unix::fs::FileExt>::write_all_at
---
hello stderr
error: unsupported operation: syscall: unsupported syscall number 328
##[error]  --> /checkout/library/std/src/sys/pal/unix/weak/syscall.rs:15:26
   |
LL |                   unsafe { libc::syscall(libc::${concat(SYS_, $name)}, $($param),*) as $ret }
   |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unsupported operation occurred here
   |
  ::: /checkout/library/std/src/sys/fd/unix.rs:669:9
   |
LL | /         syscall!(
LL | |             fn pwritev2(
LL | |                 fd: libc::c_int,
LL | |                 iovec: *const libc::iovec,
...  |
LL | |             ) -> isize;
LL | |         );
   | |_________- in this macro invocation
   |
   = help: this is likely not a bug in the program; it indicates that the program performed an operation that Miri does not support
   = note: stack backtrace:
           0: std::sys::fd::unix::FileDesc::pwritev2::pwritev2
               at /checkout/library/std/src/sys/pal/unix/weak/syscall.rs:15:26: 15:82
           1: std::sys::fd::unix::FileDesc::pwritev2
               at /checkout/library/std/src/sys/fd/unix.rs:701:21: 707:18
           2: std::sys::fd::unix::FileDesc::write_at
               at /checkout/library/std/src/sys/fd/unix.rs:420:32: 420:59
           3: std::sys::fs::unix::File::write_at
               at /checkout/library/std/src/sys/fs/unix.rs:1517:9: 1517:37
           4: <std::fs::File as std::os::unix::fs::FileExt>::write_at
               at /checkout/library/std/src/os/unix/fs.rs:382:9: 382:46
           5: <std::fs::File as std::os::unix::fs::FileExt>::write_all_at
---

Location:
   /cargo/registry/src/index.crates.io-1949cf8c6b5b557f/ui_test-0.30.7/src/lib.rs:365

Backtrace omitted. Run with RUST_BACKTRACE=1 environment variable to display it.
Run with RUST_BACKTRACE=full to include source snippets.
error: test failed, to rerun pass `--test ui`

Caused by:
  process didn't exit successfully: `/checkout/obj/build/x86_64-unknown-linux-gnu/stage2-tools/x86_64-unknown-linux-gnu/release/build/miri/886b09df76b2b02a/out/ui-886b09df76b2b02a` (exit status: 1)
Command `/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo test --target x86_64-unknown-linux-gnu -Zbinary-dep-depinfo -j 4 -Zroot-dir=/checkout -Zembed-metadata=no --locked --color=always --profile=release --manifest-path /checkout/src/tools/miri/Cargo.toml -- [workdir=/checkout]` failed with exit code 1
Created at: src/bootstrap/src/core/build_steps/tool.rs:208:21
Executed at: src/bootstrap/src/core/build_steps/test.rs:790:19

Command has failed. Rerun with -v to see more details.
Bootstrap failed while executing `test --stage 2 miri cargo-miri`
Currently active steps:
test::Miri { target: x86_64-unknown-linux-gnu } at src/bootstrap/src/core/build_steps/test.rs:716
Build completed unsuccessfully in 0:46:10
  local time: Sun Nov  8 01:12:18 UTC 2026