Messages in this thread | | | Date | Thu, 12 Jan 2023 17:14:52 +0100 | From | Borislav Petkov <> | Subject | Re: [bp:tip-x86-alternatives 1/1] error[E0588]: packed type cannot transitively contain a `#[repr(align)]` type |
| |
On Sat, Jan 07, 2023 at 01:38:42AM +0100, Miguel Ojeda wrote: > You are of course right that the instructions are not complete, I just > meant to add a bit of context, i.e. that Rust got enabled due to the > config, but as far as I understand, it shouldn't be getting enabled in > the other ones for the moment.
Right, or at least the repro instructions should state it clear.
Btw, this is part of a long-running feedback process we're giving to the 0day bot in order to make their reports as user friendly as possible.
> My point was that the script expects some variables set by `Makefile`, > similar to `$CC` etc., so that output does not imply you have (or not) > a suitable Rust toolchain installed (i.e. it will currently also fail > if you have it installed).
Aha.
> Meanwhile (of course it is not the same as proper reproduction > instructions since the LKP team may do something different), the > documentation on how to set it up for a normal developer is at: > https://www.kernel.org/doc/html/latest/rust/quick-start.html, in case > it helps (if you are up for it... :)
Probably that link should be part of those reproduction instructions.
> > And while we're reporting bugs: the error message from the compiler itself could > > use some "humanization" - I have zero clue what it is trying to tell me. > > What would you want to see? We can ask the relevant Rust team to see > if they can improve it. > > In general, note that you can ask `rustc` to further explain an error > giving it the code with `--explain`. The compiler suggests this > itself, but sadly the robot cut it out :(
Well, I find having an --explain option too much. But there are perhaps reasons for it.
One improvement could be, IMHO, they could turn on --explain automatically when it results in a build error. So that you don't have to do it yourself.
What would be better, tho, is if there were no --explain option at all and the warnings are as human readable as possible.
> For more information about this error, try `rustc --explain E0588` > > In this case, it gives: > > A type with `packed` representation hint has a field with `align` > representation hint. > ...
so the struct is:
struct alt_instr { s32 instr_offset; /* original instruction */ s32 repl_offset; /* offset to replacement instruction */
union { struct { u32 cpuid: 16; /* CPUID bit set for replacement */ u32 flags: 16; /* patching control flags */ }; u32 ft_flags; };
u8 instrlen; /* length of original instruction */ u8 replacementlen; /* length of new instruction */ } __packed;
and everything is naturally aligned.
So I'm guessing this is a rust bindings glue shortcoming or so...
Thx.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
| |