From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 4E0B9429CDD; Thu, 16 Jul 2026 13:24:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784208262; cv=none; b=ONq29bZ5WRpQFnRfBVXBjCAaJoJpkeeeBg0fzbEz7uxZBN6yClXWVIVv8cM9wPw4FmtHZs9Qypqa5VWtwDchHeSjefRKeXGGcqi1nN7tmXtFxjnXluC+9bIoiLxlO/J7PLDlJuSME4l2sGvJRm46LAqsAWOxuzWFzdLjxEC8w4g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784208262; c=relaxed/simple; bh=W9EsE9F2BjLh9oxv08i2aA5THwluUzeMtjMrevk0Rj8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ndn4t7vNz2hrq0j4BGge+nF0T1qDaXUstVzNdHfy9YrNZaTba8rwWnzndMp96DrXq3HQnuRfQZA96KIdqrkwY45OUx0SH9SOvGGc9TvopLLOTY0y1T8K740iMHRAAITfuKDbnBcdy6xr4kNJji6hve8DyEhbFpxPRC3pHCC7Un8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=H76DTIww; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="H76DTIww" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B1AE41F00A3E; Thu, 16 Jul 2026 13:24:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784208261; bh=pviMfnX/HUaOmx/ovGW50P9j3K4uudlc7YTeokSyPvE=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=H76DTIwwU8Z72uPRHja7ie2zD8snRxH7/gCNKaWMv6sk/6GsfZoYKdczqoJhsLPGt pwV03mBycS61lRZn9ovWs8wXMGJs55CECUzKcSeRqdPaALEVbn7LLXluCitQeQcNPb zywiB/k0km18wCd1EW6LUYZpjOo26guc22ctDzakcYhztOQr6BjaHmch6x4bc7/aad 7Qvtdyewx4crUQqOHjjgqCw6DMYPJLC8jcxFpw8knR20bh+fsHunXCBvLANptTrLuS M5bn65A8Jm1JHboMxIKZo3r37oAxYXi4WpnsnDHmVCdcRQL2gCNwmlS4xdcjBo35eY tz8YLt8kD4U3A== Date: Thu, 16 Jul 2026 14:24:15 +0100 From: Will Deacon To: Pu Hu Cc: "mhiramat@kernel.org" , "ada.coupriediaz@arm.com" , "catalin.marinas@arm.com" , "davem@davemloft.net" , Hongyan Xia , Jiazi Li , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-trace-kernel@vger.kernel.org" , "naveen@kernel.org" , "yang@os.amperecomputing.com" Subject: Re: [RFC v3 2/2] arm64: kprobes: Allow reentering kprobes while single-stepping Message-ID: References: <20260710063242.228714-1-hupu@transsion.com> <20260710063242.228714-3-hupu@transsion.com> 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-Disposition: inline In-Reply-To: <20260710063242.228714-3-hupu@transsion.com> On Fri, Jul 10, 2026 at 06:32:55AM +0000, Pu Hu wrote: > From: Pu Hu > > A kprobe can be hit while another kprobe is in KPROBE_HIT_SS state. This > can happen when tracing or perf code runs from the debug exception path > while the first kprobe is preparing or executing its out-of-line > single-step instruction. I don't understand this part. The single-step runs with debug exceptions disabled (kprobes_save_local_irqflag() sets PSTATE.D) so how do we end up taking one? Will