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From: Nam Cao <namcao@linutronix.de>
To: Vladimir Kondratiev <vladimir.kondratiev@mobileye.com>,
	Paul Walmsley <pjw@kernel.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Alexandre Ghiti <alex@ghiti.fr>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Oleg Nesterov <oleg@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>
Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	linux-trace-kernel@vger.kernel.org,
	Vladimir Kondratiev <vladimir.kondratiev@mobileye.com>
Subject: Re: [PATCH v2 2/2] riscv: probes: reject probes inside an LR/SC sequence
Date: Thu, 12 Nov 2026 08:54:49 +0100	[thread overview]
Message-ID: <87jymicwmu.fsf@yellow.woof> (raw)
In-Reply-To: <20261111-probes-in-lrsc-v2-2-b2525b7e1e8e@mobileye.com>

Vladimir Kondratiev <vladimir.kondratiev@mobileye.com> writes:
> A kprobe or uprobe replaces an instruction with a breakpoint. The trap
> clears the hart's reservation, so if the breakpoint sits on the lr, on
> the sc, or on any instruction between them, the sc fails, the loop
> branches back to the lr and the probe fires again. The sequence never
> completes.

Xiaofeng sent a series addressing the same issue:
https://lore.kernel.org/linux-riscv/20261019134121.1763-1-yuanxiaofeng@eswincomputing.com/#t

I have only skimmed this patch, but this patch has an important
difference: riscv_probe_in_lrsc_body(), while the other series
implements a kunit.

Perhaps you two should join forces?

Nam

WARNING: multiple messages have this Message-ID (diff)
From: Nam Cao <namcao@linutronix.de>
To: Vladimir Kondratiev <vladimir.kondratiev@mobileye.com>,
	Paul Walmsley <pjw@kernel.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Alexandre Ghiti <alex@ghiti.fr>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Oleg Nesterov <oleg@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>
Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	linux-trace-kernel@vger.kernel.org,
	Vladimir Kondratiev <vladimir.kondratiev@mobileye.com>
Subject: Re: [PATCH v2 2/2] riscv: probes: reject probes inside an LR/SC sequence
Date: Thu, 12 Nov 2026 08:54:49 +0100	[thread overview]
Message-ID: <87jymicwmu.fsf@yellow.woof> (raw)
In-Reply-To: <20261111-probes-in-lrsc-v2-2-b2525b7e1e8e@mobileye.com>

Vladimir Kondratiev <vladimir.kondratiev@mobileye.com> writes:
> A kprobe or uprobe replaces an instruction with a breakpoint. The trap
> clears the hart's reservation, so if the breakpoint sits on the lr, on
> the sc, or on any instruction between them, the sc fails, the loop
> branches back to the lr and the probe fires again. The sequence never
> completes.

Xiaofeng sent a series addressing the same issue:
https://lore.kernel.org/linux-riscv/20261019134121.1763-1-yuanxiaofeng@eswincomputing.com/#t

I have only skimmed this patch, but this patch has an important
difference: riscv_probe_in_lrsc_body(), while the other series
implements a kunit.

Perhaps you two should join forces?

Nam

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linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

  parent reply	other threads:[~2026-11-12  7:54 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-11-11 17:01 [PATCH v2 0/2] riscv: probes: reject probes inside an LR/SC sequence Vladimir Kondratiev
2026-11-11 17:01 ` Vladimir Kondratiev
2026-11-11 17:01 ` [PATCH v2 1/2] riscv: kprobes: fix out-of-bounds read in riscv_probe_decode_insn Vladimir Kondratiev
2026-11-11 17:01   ` Vladimir Kondratiev
2026-11-11 17:13   ` sashiko-bot
2026-11-11 17:01 ` [PATCH v2 2/2] riscv: probes: reject probes inside an LR/SC sequence Vladimir Kondratiev
2026-11-11 17:01   ` Vladimir Kondratiev
2026-11-11 17:21   ` sashiko-bot
2026-11-12  7:54   ` Nam Cao [this message]
2026-11-12  7:54     ` Nam Cao
2026-11-12 11:19     ` Vladimir Kondratiev
2026-11-12 11:19       ` Vladimir Kondratiev

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