From: Peter Zijlstra <peterz@infradead.org>
To: Rustam Kovhaev <rkovhaev@gmail.com>
Cc: Sami Tolvanen <samitolvanen@google.com>,
Alexei Starovoitov <ast@kernel.org>,
linux-kernel@vger.kernel.org, bpf@vger.kernel.org
Subject: Re: kernel crashes in BPF JIT code with kCFI and clang on x86
Date: Wed, 7 Jan 2026 16:44:04 +0100 [thread overview]
Message-ID: <20260107154404.GJ3708021@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <20260107093639.GC3707891@noisy.programming.kicks-ass.net>
On Wed, Jan 07, 2026 at 10:36:39AM +0100, Peter Zijlstra wrote:
> On Mon, Dec 22, 2025 at 07:43:32PM -0800, Rustam Kovhaev wrote:
> > After switching to clang kbuild always generates these huge paddings in my kernel config:
> > rusty@nuc10:~/code/kbuild_rust$ grep -e IBT -e PADDING .config
> > CONFIG_CC_HAS_IBT=y
> > CONFIG_X86_KERNEL_IBT=y
> > CONFIG_RANDOMIZE_MEMORY_PHYSICAL_PADDING=0xa
> > CONFIG_CC_HAS_ENTRY_PADDING=y
> > CONFIG_FUNCTION_PADDING_CFI=59
> > CONFIG_FUNCTION_PADDING_BYTES=59
> > CONFIG_CALL_PADDING=y
> > CONFIG_FINEIBT=y
>
> Oh gawd, you have FUNCTION_ALIGNMENT_64B. Yeah, I suppose that wasn't
> tested very well.
>
> Let me go check all that code.
I replied here:
https://lkml.kernel.org/r/20260107153603.GI3708021@noisy.programming.kicks-ass.net
but Gmail is fscking useless and figured that reply is spam. Please
consider using a 'real' mail host.
prev parent reply other threads:[~2026-01-07 15:44 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-23 3:43 kernel crashes in BPF JIT code with kCFI and clang on x86 Rustam Kovhaev
2026-01-07 9:36 ` Peter Zijlstra
2026-01-07 15:36 ` Peter Zijlstra
2026-01-10 7:58 ` Rustam Kovhaev
2026-01-07 15:44 ` Peter Zijlstra [this message]
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