Re: [PATCH net-next v3 1/7] overflow: add DEFINE_FLEX() for on-stack allocs

Re: [PATCH net-next v3 1/7] overflow: add DEFINE_FLEX() for on-stack allocs

[Przemek Kitszel]

On 8/16/23 18:35, kernel test robot wrote:
> Hi Przemek,
> 
> kernel test robot noticed the following build errors:
> 
> [auto build test ERROR on 479b322ee6feaff612285a0e7f22c022e8cd84eb]
> 
> url:    https://github.com/intel-lab-lkp/linux/commits/Przemek-Kitszel/overflow-add-DEFINE_FLEX-for-on-stack-allocs/20230816-221402
> base:   479b322ee6feaff612285a0e7f22c022e8cd84eb
> patch link:    https://lore.kernel.org/r/20230816140623.452869-2-przemyslaw.kitszel%40intel.com
> patch subject: [PATCH net-next v3 1/7] overflow: add DEFINE_FLEX() for on-stack allocs
> config: x86_64-rhel-8.3-rust (https://download.01.org/0day-ci/archive/20230817/202308170000.YqabIR9D-lkp@intel.com/config)

Rust folks, could you please tell me if this is something I should fix, 
or I just uncovered some existing bug in "unstable" thing?

Perhaps it is worth to mention, diff of v3 vs v2 is:
move dummy implementation of __has_builtin() macro to the top of 
compiler_types.h, just before `#ifndef ASSEMBLY`

Przemek

> compiler: clang version 16.0.4 (https://github.com/llvm/llvm-project.git ae42196bc493ffe877a7e3dff8be32035dea4d07)
> reproduce: (https://download.01.org/0day-ci/archive/20230817/202308170000.YqabIR9D-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202308170000.YqabIR9D-lkp@intel.com/
> 
> All errors (new ones prefixed by >>):
> 
>>> thread 'main' panicked at '"ftrace_branch_data_union_(anonymous_at_include/linux/compiler_types_h_144_2)" is not a valid Ident', /opt/cross/rustc-1.68.2-bindgen-0.56.0/cargo/registry/src/github.com-1ecc6299db9ec823/proc-macro2-1.0.24/src/fallback.rs:693:9
>     stack backtrace:
>        0: rust_begin_unwind
>                  at /rustc/9eb3afe9ebe9c7d2b84b71002d44f4a0edac95e0/library/std/src/panicking.rs:575:5
>        1: core::panicking::panic_fmt
>                  at /rustc/9eb3afe9ebe9c7d2b84b71002d44f4a0edac95e0/library/core/src/panicking.rs:64:14
>        2: proc_macro2::fallback::Ident::_new
>        3: proc_macro2::Ident::new
>        4: bindgen::ir::context::BindgenContext::rust_ident
>        5: <bindgen::ir::comp::CompInfo as bindgen::codegen::CodeGenerator>::codegen
>        6: <bindgen::ir::ty::Type as bindgen::codegen::CodeGenerator>::codegen
>        7: <bindgen::ir::item::Item as bindgen::codegen::CodeGenerator>::codegen
>        8: <bindgen::ir::comp::CompInfo as bindgen::codegen::CodeGenerator>::codegen
>        9: <bindgen::ir::ty::Type as bindgen::codegen::CodeGenerator>::codegen
>       10: <bindgen::ir::item::Item as bindgen::codegen::CodeGenerator>::codegen
>       11: <bindgen::ir::module::Module as bindgen::codegen::CodeGenerator>::codegen
>       12: <bindgen::ir::item::Item as bindgen::codegen::CodeGenerator>::codegen
>       13: bindgen::ir::context::BindgenContext::gen
>       14: bindgen::Builder::generate
>       15: bindgen::main
>     note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
>     make[3]: *** [rust/Makefile:316: rust/uapi/uapi_generated.rs] Error 1
>     make[3]: *** Deleting file 'rust/uapi/uapi_generated.rs'
>>> thread 'main' panicked at '"ftrace_branch_data_union_(anonymous_at_include/linux/compiler_types_h_144_2)" is not a valid Ident', /opt/cross/rustc-1.68.2-bindgen-0.56.0/cargo/registry/src/github.com-1ecc6299db9ec823/proc-macro2-1.0.24/src/fallback.rs:693:9
>     stack backtrace:
>        0: rust_begin_unwind
>                  at /rustc/9eb3afe9ebe9c7d2b84b71002d44f4a0edac95e0/library/std/src/panicking.rs:575:5
>        1: core::panicking::panic_fmt
>                  at /rustc/9eb3afe9ebe9c7d2b84b71002d44f4a0edac95e0/library/core/src/panicking.rs:64:14
>        2: proc_macro2::fallback::Ident::_new
>        3: proc_macro2::Ident::new
>        4: bindgen::ir::context::BindgenContext::rust_ident
>        5: <bindgen::ir::comp::CompInfo as bindgen::codegen::CodeGenerator>::codegen
>        6: <bindgen::ir::ty::Type as bindgen::codegen::CodeGenerator>::codegen
>        7: <bindgen::ir::item::Item as bindgen::codegen::CodeGenerator>::codegen
>        8: <bindgen::ir::comp::CompInfo as bindgen::codegen::CodeGenerator>::codegen
>        9: <bindgen::ir::ty::Type as bindgen::codegen::CodeGenerator>::codegen
>       10: <bindgen::ir::item::Item as bindgen::codegen::CodeGenerator>::codegen
>       11: <bindgen::ir::module::Module as bindgen::codegen::CodeGenerator>::codegen
>       12: <bindgen::ir::item::Item as bindgen::codegen::CodeGenerator>::codegen
>       13: bindgen::ir::context::BindgenContext::gen
>       14: bindgen::Builder::generate
>       15: bindgen::main
>     note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
>     make[3]: *** [rust/Makefile:310: rust/bindings/bindings_generated.rs] Error 1
>     make[3]: *** Deleting file 'rust/bindings/bindings_generated.rs'
>     make[3]: Target 'rust/' not remade because of errors.
>     make[2]: *** [Makefile:1293: prepare] Error 2
>     make[1]: *** [Makefile:234: __sub-make] Error 2
>     make[1]: Target 'prepare' not remade because of errors.
>     make: *** [Makefile:234: __sub-make] Error 2
>     make: Target 'prepare' not remade because of errors.
> 

Re: [PATCH net-next v3 1/7] overflow: add DEFINE_FLEX() for on-stack allocs

[Miguel Ojeda]

On Fri, Aug 18, 2023 at 12:38 PM Przemek Kitszel
<przemyslaw.kitszel@intel.com> wrote:
>
> Rust folks, could you please tell me if this is something I should fix,
> or I just uncovered some existing bug in "unstable" thing?
>
> Perhaps it is worth to mention, diff of v3 vs v2 is:
> move dummy implementation of __has_builtin() macro to the top of
> compiler_types.h, just before `#ifndef ASSEMBLY`

Nothing you need to worry about, it is an issue with old `bindgen` and
LLVM >= 16, fixed in commit 08ab786556ff ("rust: bindgen: upgrade to
0.65.1") which is in `rust-next` at the moment. Sorry about that, and
thanks for pinging us!

LKP / Yujie / Philip: since we got a few reports on this, would it be
possible to avoid LLVM >= 16 for Rust-enabled builds for any branch
that does not include the new `bindgen` or at least 08ab786556ff? Or,
if Greg is OK with that, I guess we could also backport the upgrade,
but perhaps it is a bit too much for stable?

Cheers,
Miguel

Re: [PATCH net-next v3 1/7] overflow: add DEFINE_FLEX() for on-stack allocs

[Philip Li]

On Fri, Aug 18, 2023 at 01:10:07PM +0200, Miguel Ojeda wrote:
> On Fri, Aug 18, 2023 at 12:38 PM Przemek Kitszel
> <przemyslaw.kitszel@intel.com> wrote:
> >
> > Rust folks, could you please tell me if this is something I should fix,
> > or I just uncovered some existing bug in "unstable" thing?
> >
> > Perhaps it is worth to mention, diff of v3 vs v2 is:
> > move dummy implementation of __has_builtin() macro to the top of
> > compiler_types.h, just before `#ifndef ASSEMBLY`
> 
> Nothing you need to worry about, it is an issue with old `bindgen` and
> LLVM >= 16, fixed in commit 08ab786556ff ("rust: bindgen: upgrade to
> 0.65.1") which is in `rust-next` at the moment. Sorry about that, and
> thanks for pinging us!
> 
> LKP / Yujie / Philip: since we got a few reports on this, would it be
> possible to avoid LLVM >= 16 for Rust-enabled builds for any branch
> that does not include the new `bindgen` or at least 08ab786556ff? Or,

Got it, we will update the bot to handle this to avoid further false
positive.

> if Greg is OK with that, I guess we could also backport the upgrade,
> but perhaps it is a bit too much for stable?
> 
> Cheers,
> Miguel

Re: [PATCH net-next v3 1/7] overflow: add DEFINE_FLEX() for on-stack allocs

[Greg KH]

On Fri, Aug 18, 2023 at 01:10:07PM +0200, Miguel Ojeda wrote:
> On Fri, Aug 18, 2023 at 12:38 PM Przemek Kitszel
> <przemyslaw.kitszel@intel.com> wrote:
> >
> > Rust folks, could you please tell me if this is something I should fix,
> > or I just uncovered some existing bug in "unstable" thing?
> >
> > Perhaps it is worth to mention, diff of v3 vs v2 is:
> > move dummy implementation of __has_builtin() macro to the top of
> > compiler_types.h, just before `#ifndef ASSEMBLY`
> 
> Nothing you need to worry about, it is an issue with old `bindgen` and
> LLVM >= 16, fixed in commit 08ab786556ff ("rust: bindgen: upgrade to
> 0.65.1") which is in `rust-next` at the moment. Sorry about that, and
> thanks for pinging us!
> 
> LKP / Yujie / Philip: since we got a few reports on this, would it be
> possible to avoid LLVM >= 16 for Rust-enabled builds for any branch
> that does not include the new `bindgen` or at least 08ab786556ff? Or,
> if Greg is OK with that, I guess we could also backport the upgrade,
> but perhaps it is a bit too much for stable?

Commit is tiny enough for stable backports if it fixes a real issue that
everyone needs to address, so I have no objection to taking it for
stable releases once it hits Linus's tree.

thanks,

greg k-h