From: Heiko Carstens <hca@linux.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Mukesh Kumar Chaurasiya <mkchauras@gmail.com>,
catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com,
maddy@linux.ibm.com, mpe@ellerman.id.au, npiggin@gmail.com,
chleroy@kernel.org, ritesh.list@gmail.com, sshegde@linux.ibm.com,
pjw@kernel.org, palmer@dabbelt.com, aou@eecs.berkeley.edu,
alex@ghiti.fr, gor@linux.ibm.com, agordeev@linux.ibm.com,
borntraeger@linux.ibm.com, svens@linux.ibm.com, tglx@kernel.org,
mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com,
x86@kernel.org, hpa@zytor.com, ojeda@kernel.org,
boqun@kernel.org, gary@garyguo.net, bjorn3_gh@protonmail.com,
lossin@kernel.org, a.hindborg@kernel.org, aliceryhl@google.com,
tmgross@umich.edu, dakr@kernel.org, daniel.almeida@collabora.com,
tamird@kernel.org, acourbot@nvidia.com, work@onurozkan.dev,
nathan@kernel.org, ndesaulniers@google.com, morbo@google.com,
justinstitt@google.com, jszhang@kernel.org, japo@linux.ibm.com,
jpoimboe@kernel.org, seanjc@google.com, pmladek@suse.com,
thuth@redhat.com, ynorov@nvidia.com, joelagnelf@nvidia.com,
david@davidgow.net, fujita.tomonori@gmail.com,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org,
rust-for-linux@vger.kernel.org, llvm@lists.linux.dev
Subject: Re: [RFC] rust: kernel: Add KUnit tests for ARCH_WARN_ASM bug table emission
Date: Thu, 24 Sep 2026 17:13:35 +0200 [thread overview]
Message-ID: <20260924151335.18402A8b-hca@linux.ibm.com> (raw)
In-Reply-To: <20260924111557.GP1837346@noisy.programming.kicks-ass.net>
On Thu, Sep 24, 2026 at 01:15:57PM +0200, Peter Zijlstra wrote:
> Untested thingies for arm64 and s390x.
...
> diff --git a/arch/s390/kernel/traps.c b/arch/s390/kernel/traps.c
> index b6ba4465f59d..8bbb082fd5e3 100644
> --- a/arch/s390/kernel/traps.c
> +++ b/arch/s390/kernel/traps.c
> @@ -26,6 +26,7 @@
> #include <linux/entry-common.h>
> #include <linux/kmsan.h>
> #include <linux/bug.h>
> +#include <linux/uaccess.h>
> #include <asm/entry-percpu.h>
> #include <asm/asm-extable.h>
> #include <asm/irqflags.h>
> @@ -55,7 +56,12 @@ static inline void __user *get_trap_ip(struct pt_regs *regs)
> #ifdef CONFIG_GENERIC_BUG
> int is_valid_bugaddr(unsigned long addr)
> {
> - return 1;
> + u16 insn;
> +
> + if (get_kernel_nofault(insn, (u16 *)addr))
> + return 0;
> +
> + return insn == 0x0001 || insn == 0x000e;
I have no idea why anybody wants to do this, but it looks like I'm not
alone :) In any case: the check is wrong.
s390 uses only the monitor call instruction and this should be
return insn == 0xaf00;
At least it is not possible to set a kprobe on bug instructions, which
would make this "interesting".
next prev parent reply other threads:[~2026-09-24 15:14 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-22 5:50 Mukesh Kumar Chaurasiya (IBM)
2026-09-22 6:47 ` Peter Zijlstra
2026-09-23 6:28 ` Mukesh Kumar Chaurasiya
2026-09-24 11:15 ` Peter Zijlstra
2026-09-24 12:46 ` Mark Rutland
2026-09-24 12:52 ` Peter Zijlstra
2026-09-24 13:05 ` Mark Rutland
2026-09-24 15:13 ` Heiko Carstens [this message]
2026-09-24 12:31 ` Mark Rutland
2026-09-24 13:00 ` Christophe Leroy (CS GROUP)
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