From: Andreas Hindborg <a.hindborg@kernel.org>
To: "FUJITA Tomonori" <fujita.tomonori@gmail.com>
Cc: <linux-kernel@vger.kernel.org>, <rust-for-linux@vger.kernel.org>,
<x86@kernel.org>, <linux-riscv@lists.infradead.org>,
<linux-arm-kernel@lists.infradead.org>,
<loongarch@lists.linux.dev>, <tglx@linutronix.de>,
<mingo@redhat.com>, <bp@alien8.de>,
<dave.hansen@linux.intel.com>, <peterz@infradead.org>,
<hpa@zytor.com>, <paul.walmsley@sifive.com>,
<palmer@dabbelt.com>, <aou@eecs.berkeley.edu>,
<catalin.marinas@arm.com>, <will@kernel.org>,
<chenhuacai@kernel.org>, <kernel@xen0n.name>,
<tangyouling@loongson.cn>, <hejinyang@loongson.cn>,
<yangtiezhu@loongson.cn>, <ojeda@kernel.org>,
<alex.gaynor@gmail.com>, <boqun.feng@gmail.com>,
<gary@garyguo.net>, <bjorn3_gh@protonmail.com>,
<benno.lossin@proton.me>, <aliceryhl@google.com>,
<tmgross@umich.edu>
Subject: Re: [PATCH v3 0/5] rust: Add bug/warn abstractions
Date: Thu, 27 Feb 2025 09:28:11 +0100 [thread overview]
Message-ID: <87frjzu6zo.fsf@kernel.org> (raw)
In-Reply-To: <20250227.155417.1610168537890385926.fujita.tomonori@gmail.com> (FUJITA Tomonori's message of "Thu, 27 Feb 2025 15:54:17 +0900")
"FUJITA Tomonori" <fujita.tomonori@gmail.com> writes:
> On Wed, 26 Feb 2025 20:39:45 +0100
> Andreas Hindborg <a.hindborg@kernel.org> wrote:
>
>> How does this series compare/overlap with [1] ?
>>
>> [1] https://lore.kernel.org/all/20241126-pr_once_macros-v4-0-410b8ca9643e@tuta.io/
>
> No overlap. Each solves a different problem. Both are necessary.
>
> This patchset enables Rust code to call C's BUG/WARN properly.
>
> Currently, Rust's BUG() is a simple wrapper for C's BUG()
> (rust/helpers/bug.c). I added BUG() to rnull's init() and got the
> following:
>
> # insmod /root/rnull_mod.ko
> rnull_mod: Rust null_blk loaded
> ------------[ cut here ]------------
> kernel BUG at rust/helpers/bug.c:7!
> Oops: invalid opcode: 0000 [#1] SMP
> CPU: 0 UID: 0 PID: 31 Comm: insmod Not tainted 6.14.0-rc1+ #103
> RIP: 0010:rust_helper_BUG+0x8/0x10
> (snip)
>
> This is NOT debug information that we expect. The problem is that
> BUG/WARN feature (lib/bug.c) can only be used from assembly.
>
> This patchset includes only warn() but with bug() implementation on
> top of this patchset, I got:
>
> # insmod /root/rnull_mod.ko
> rnull_mod: Rust null_blk loaded
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 31 at /home/fujita/git/linux-rust/drivers/block/rnull.rs:46 _RNvXCsafUg3oOYix8_5rnullNtB2_13NullBlkModu]
> Modules linked in: rnull_mod(+)
> CPU: 0 UID: 0 PID: 31 Comm: insmod Not tainted 6.14.0-rc1+ #104
> RIP: 0010:_RNvXCsafUg3oOYix8_5rnullNtB2_13NullBlkModuleNtCsaYBeKL739Xz_6kernel13InPlaceModule4init+0x71/0x4f0 [rnull_mod]
>
>
> The [1] patchset adds an abstraciton for include/linux/once_lite.h,
> 'call a function once' feature, with pr_*_once() implementation.
>
> pr_*_once() just calls printk() once. Unlike BUG/WARN, no debug
> information (call place, registers, stack trace, etc).
>
>
> The only connection between two patchset is that WARN_ONCE() can be
> built on top of both like the C side.
Awesome, thanks for explaining 👍
Best regards,
Andreas Hindborg
prev parent reply other threads:[~2025-02-27 8:28 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <yy_ESUuchCjlaGIJHzCPAcP_d9ucSD0CGXaoZNNkY7BmN5Ch1J8avsA9QpKO5LkTjlGpu99jl8NrFl5NFSQXuw==@protonmail.internalid>
2025-02-13 13:57 ` [PATCH v3 0/5] rust: Add bug/warn abstractions FUJITA Tomonori
2025-02-13 13:57 ` [PATCH v3 1/5] x86/bug: Add ARCH_WARN_ASM macro for BUG/WARN asm code sharing with Rust FUJITA Tomonori
2025-02-13 13:57 ` [PATCH v3 2/5] riscv/bug: " FUJITA Tomonori
2025-02-28 10:13 ` Alexandre Ghiti
2025-02-13 13:57 ` [PATCH v3 3/5] arm64/bug: " FUJITA Tomonori
2025-02-26 19:27 ` Catalin Marinas
2025-02-27 7:01 ` FUJITA Tomonori
2025-02-13 13:57 ` [PATCH v3 4/5] loongarch/bug: " FUJITA Tomonori
2025-02-13 13:57 ` [PATCH v3 5/5] rust: Add warn_on and warn_on_once FUJITA Tomonori
2025-03-03 13:33 ` Alice Ryhl
2025-03-05 5:13 ` FUJITA Tomonori
2025-03-05 8:42 ` Alice Ryhl
2025-03-05 10:24 ` FUJITA Tomonori
2025-03-05 10:36 ` Alice Ryhl
2025-02-26 19:39 ` [PATCH v3 0/5] rust: Add bug/warn abstractions Andreas Hindborg
2025-02-27 6:54 ` FUJITA Tomonori
2025-02-27 8:28 ` Andreas Hindborg [this message]
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