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From: Breno Leitao <leitao@debian.org>
To: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
	 Catalin Marinas <catalin.marinas@arm.com>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	 Jinjie Ruan <ruanjinjie@huawei.com>,
	linux-arm-kernel@lists.infradead.org,
	 linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
	rmikey@meta.com, kernel-team@meta.com,
	 Vladimir Murzin <vladimir.murzin@arm.com>,
	Ada Couprie Diaz <ada.coupriediaz@arm.com>
Subject: Re: [PATCH RFC] arm64: entry: PSTATE_I_SET is leaking on pseudo NMI mode
Date: Mon, 10 Aug 2026 05:59:49 -0700	[thread overview]
Message-ID: <annJFhJU5XVE8NKm@gmail.com> (raw)
In-Reply-To: <anm5T9FazACqOWXF@willie-the-truck>

On Mon, Aug 10, 2026 at 12:43:11PM +0100, Will Deacon wrote:
> On Fri, Aug 07, 2026 at 09:29:12AM -0700, Breno Leitao wrote:
> > On Fri, Aug 07, 2026 at 07:58:21AM -0700, Breno Leitao wrote:
> > > Meanwhile, I will try to ftrace the writes to PMR and regs->pmr to get
> > > a better grasp of the states machine we are in (probably on Monday).
> > 
> > It seems LLM found a very easy to reproduce this:
> > 
> > 	bash-5.1# dmesg
> > 
> > 	bash-5.1#  cd /sys/kernel/tracing
> > 	echo 'r:pmr vfs_read bad=+0($retval):u64' >> kprobe_events
> > 	echo 1 > events/kprobes/pmr/enable
> 
> Nice, that triggers straightforwardly in QEMU for me. The diff below
> (which implements my suggestion from [1]) seems to fix the issue, but
> it would be good to hear feedback from one of the Arm folks.

I've tested the patch on my machines, and it fixes all the cases I've
got.

If it is useful:
  Tested-by: Breno Leitao <leitao@debian.org>

Thanks for looking at it,
--breno

      parent reply	other threads:[~2026-08-10 13:00 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-07 11:45 [PATCH RFC] arm64: entry: PSTATE_I_SET is leaking on pseudo NMI mode Breno Leitao
2026-08-07 13:40 ` Will Deacon
2026-08-07 13:57 ` Mark Rutland
2026-08-07 14:49   ` Vladimir Murzin
2026-08-10 12:44     ` Jinjie Ruan
2026-08-10 13:04       ` Vladimir Murzin
2026-08-07 14:58   ` Breno Leitao
2026-08-07 16:29     ` Breno Leitao
2026-08-10 11:43       ` Will Deacon
2026-08-10 12:42         ` Vladimir Murzin
2026-08-10 15:05           ` Will Deacon
2026-08-10 16:39             ` Vladimir Murzin
2026-08-10 12:51         ` Jinjie Ruan
2026-08-10 12:59         ` Breno Leitao [this message]

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