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5 commits

Author SHA1 Message Date
Philipp Schuster
02da2f2d36 misc: gitlint: python code improvements
Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
On-behalf-of: SAP philipp.schuster@sap.com
2025-11-13 19:16:45 +00:00
Philipp Schuster
62345cd6fd misc: gitlint: allow more prefixes disabling 72 width limit
Suggested-by Alyssa Ross [0].

[0]: https://github.com/cloud-hypervisor/cloud-hypervisor/pull/7471#discussion_r2519894440

Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
On-behalf-of: SAP philipp.schuster@sap.com
2025-11-13 19:16:45 +00:00
Philipp Schuster
f826d92601 misc: gitlint: allow well-known commit tags to exceed line limit
To get that list, I've used

```
git log | grep --fixed-strings -- "-by:" | head -n 100000 | sort | less
```

on the Linux kernel's git repository.

Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
On-behalf-of: SAP philipp.schuster@sap.com
2025-11-13 19:16:45 +00:00
Philipp Schuster
d580ed55c6 seccomp: add SYS_getcwd (79) to support proper Rust backtraces
When a proper Rust backtrace is printed, the Rust std wants to use the
SYS_getcwd(79) system call to prettify some paths while printing. In
Cloud Hypervisor, this is at least relevant for printing panics or if
a `anyhow::Error` value is printed using `{e:?}` (but not `{e:#?}`).

The syscall cause can be found in `impl fmt::Display for Backtrace {}`
in `library/std/src/backtrace.rs`.

Without this addition, the seccomp violation of the SYS_getcwd (79)
hinders the proper error message including a full backtrace from showing
up. This annoying behaviour already delayed many debugging efforts. With
this fix, things just work. The new syscall itself should be pretty
harmless for normal operation.

```
thread 'vmm' panicked at virtio-devices/src/rng.rs:224:9:
Yikes, things went horribly wrong!

==== Possible seccomp violation ====
Try running with `strace -ff` to identify the cause and open an issue: https://github.com/cloud-hypervisor/cloud-hypervisor/issues/new
[1]    287683 invalid system call (core dumped)  RUST_BACKTRACE=full cargo run --bin cloud-hypervisor -- --api-socket  --kerne
```

```
thread 'vmm' panicked at virtio-devices/src/rng.rs:224:9:
Yikes, things went horribly wrong!
stack backtrace:
   0:     0x557d91286b62 - std::backtrace_rs::backtrace::libunwind::trace::hc20b48b31ee52608
                               at /rustc/17067e9ac6d7ecb70e50f92c1944e545188d2359/library/std/src/../../backtrace/src/backtrace/libunwind.rs:117:9
   1:     0x557d91286b62 - std::backtrace_rs::backtrace::trace_unsynchronized::h5d207cd20f193d88
                               at /rustc/17067e9ac6d7ecb70e50f92c1944e545188d2359/library/std/src/../../backtrace/src/backtrace/mod.rs:66:14

...

  67:                0x0 - <unknown>
Error: Cloud Hypervisor exited with the following error:
  Failed to join on VMM thread: Any { .. }

Debug Info: ThreadJoin(Any { .. })
```

- add any panic, for example into the create or drop function of a
  device
- add --seccomp=true|log to analyze the situation

Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
On-behalf-of: SAP philipp.schuster@sap.com
2025-06-26 20:50:57 +00:00
Philipp Schuster
77e042237d ci: improve gitlint (max line length in body with exceptions)
Follow-up of 5aa1540c5d but way more
mature. We now use custom gitlint rules written in Python to better
handle the max line length, with respect to a few valid exceptions.
Recognizing code blocks or compiler output, as discussed, is not
trivial and hard to get right for all corner-cases. Therefore, this
commit is a pragmatic way forward. The CI job should be kept optional.

Allowed exceptions for the 72 line length limit are now:

1. links in the following three common patterns:
https://example.com/very-long-links/very-long-links/very-long-links/very-long-links/very-long-links/very-long-links/very-long-links
[0] https://example.com/very-long-links/very-long-links/very-long-links/very-long-links/very-long-links/very-long-links/very-long-links
[0]: https://example.com/very-long-links/very-long-links/very-long-links/very-long-links/very-long-links/very-long-links/very-long-links

2. code blocks (anything between the three backticks)

```
let x = "very_long_very_long_very_long_very_long_very_long_very_long_very_long_very_long_very_long_very_long_"
```

Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
On-behalf-of: SAP philipp.schuster@sap.com
2025-05-09 14:50:23 +01:00