From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 40141189F20; Mon, 17 Nov 2025 02:46:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763347591; cv=none; b=EGf5eogcRY8BAQOQQgf8joHv30i7+ckMSpjjC9kzbDt9wWmkMzRBWeymQ1AbFCgUDXFDJPbaQq3OnZFMzL6DPcPzueLSXwFHd5vZBD0G2VF+gDQnp24Zx5PdIjjkD4NWegZlZ4i7MNCToWK7Cqp2EWtLjzFhS2MSJGtd70yjSL4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763347591; c=relaxed/simple; bh=WckId20dWoL3Sm2pBxpsSPNRW6RlT7Dsm6IF/ZnMV/g=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=NoWCBOEYVNFnfQ21NE6NbKf5v7hoWRRvN/9px9Y/DzK/clQHl502YC2PDUI805lU/qAY+E/ggFwux6ljJpeefx4LOKdUKtCTE6qZi35QwPliZ+7zus6CcScAnS9/vh3SmR66G8WM9ktaoQoil3gX9ZapiMFOAAwWVk468MKBHes= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Jv4IAyaO; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Jv4IAyaO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 18A73C4CEF5; Mon, 17 Nov 2025 02:46:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763347590; bh=WckId20dWoL3Sm2pBxpsSPNRW6RlT7Dsm6IF/ZnMV/g=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Jv4IAyaOD4AVcvfTrSXXHEBQWq8KCAZsS3yOCC2ZnSa5zb9dGp0KP5yw9+FkNhSXf Apxz61+p14sURJhwVI6iUiRc69h5MBTw5i3wWuyKrzbLN4uTEMYFBwVGt9ZDrXMmBi SOlUmJ3/3vhGqX0zd3OTjVJUj1eh8QAHYTlwh7xypVKk7iHspdR4kdfLvYbnsp4uoO edfQ44DEBLWhjcTRBMH8cJNNQA0o5WFGgn8/SdAfWOUFoNU60L+dBGgXjYpWjCpbL6 qf4fG0tQVBbmRJMWv+kTiO0SluBlkGhXpgd2qghlM1dcPcACURQ5U4Hp2qELemiAzO yey6qXzWDSfXg== Date: Mon, 17 Nov 2025 11:46:24 +0900 From: Masami Hiramatsu (Google) To: Will Deacon Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Steven Rostedt , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , Mathieu Desnoyers , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Catalin Marinas , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 0/2] tracing/wprobe: Fix to avoid inifinite watchpoint exception on arm64 Message-Id: <20251117114624.5fc972e65edac5bb91caa4b2@kernel.org> In-Reply-To: References: <176179481538.959775.12326313742393696258.stgit@devnote2> <20251104223735.4164f224790ea0aea267dff1@kernel.org> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Fri, 14 Nov 2025 16:17:06 +0000 Will Deacon wrote: > On Tue, Nov 04, 2025 at 10:37:35PM +0900, Masami Hiramatsu wrote: > > Gently ping. > > > > There is a bugfix (or strange behavior) on arm64 hw breakpoint but > > to fix it cleanly, it should change the perf itself (but I'm not > > sure why arm64 changes the behavior only for the default overflow > > handlers.) Anyone knows it? > > It's because GDB expects to handle the stepping itself when using the > ptrace interface (with a custom overflow handler to deliver SIGTRAP). Hmm, would you mean GDB for user program? If so, it expects hw breakpoint is used by: - user-space ptrace (for GDB) - kernel-space perf (must be default overflow handler) And not expects to be used by - kernel-space custom overflow handler This series is to handle the third use case. Thank you, -- Masami Hiramatsu (Google)