From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 4238B3033C6 for ; Wed, 20 May 2026 15:13:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779289981; cv=none; b=BE3tR8cVSI8PQlY4WY/uPd6Rd7N8oPf3L3RirR5dVAEcuFsDlzOfaNu2ezzBEQ+p6bRy4q7jTZucS6I10KZAqQ4dY548ZoXsigD4rgXCQWdQ+dZFRu/izU0Xtb391IwjnipHAOYInYaYfKIrUhMJaCmS4neNupCU+AxaEwORHyQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779289981; c=relaxed/simple; bh=nGdhl1wBhwMv5gFWgIfeWfuJtU7Ra6tknEJWWjQREDY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=cnBSeU5Jj1b/kZ88kADt1abILvvpuTCV+l/adkKhmf7wP72qh2ZLknfJhTLHCc1AnYOfo9+8UHdLSQa++iAxce70uahiqSXcyoNLbRYW0zLb9AdVmZDKc7fU/i3cundcjIq4wg2/eW/eCowVOjebl2xA7IH/Pr6O9wgmhKqqMPQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=Rb6bFIo2; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=bJFPDWZM; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="Rb6bFIo2"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="bJFPDWZM" Date: Wed, 20 May 2026 17:12:57 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1779289978; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=nGdhl1wBhwMv5gFWgIfeWfuJtU7Ra6tknEJWWjQREDY=; b=Rb6bFIo29EglZzY1T4b/Y4S73+Os/B0fHIYpX61pJc0NwbCt5wYWOlMEEuByr7KE5oqK8V ZjeiCo+gjlcZg5ZlkvAhK0bErtjDZp+LAKEpAREQEA+K8k/b0GBm2Z9axZDN0LQq4ya4Xs FbJL9ATcBaceaOFRmwioP+ehl1ziAL3DMDkWHprugBxHy8vgcq+NLCWbte7Q1zKRnSZiN7 KFeL9gAEVRrdh+0AZMO94Id9YHE8NUuJ8Shxgu4Nti8k1p+bizkNeVgVb6zVZ4iJwWQG02 +gBGJVAJ/zAS06JUk6jRn3PiLHAg1A9HkvFRXeZwVVrWqIorgAEHMzdJxuYnaw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1779289978; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=nGdhl1wBhwMv5gFWgIfeWfuJtU7Ra6tknEJWWjQREDY=; b=bJFPDWZMD9ja+QnnC+MqgbgJ2Imc6VaRkvcOIK6mlBxfOaYupCPhjF2zoHn6zFzDOA4Vf2 XIFrR3qcSyyPzgBw== From: Sebastian Andrzej Siewior To: Tetsuo Handa Cc: kasan-dev , LKML , Dmitry Vyukov , Alexander Potapenko , Alan Stern , Andrew Morton , Andrey Konovalov , Andrey Konovalov , Clark Williams , Greg Kroah-Hartman , Marco Elver Subject: Re: [PATCH v3] kcov: move kcov_remote_data to task_struct for RT and remove local_lock Message-ID: <20260520151257.9s5600PG@linutronix.de> References: <1956540a-e458-4a44-854b-11ff07cb1072@I-love.SAKURA.ne.jp> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: On 2026-05-09 17:09:44 [+0900], Tetsuo Handa wrote: > In CONFIG_PREEMPT_RT=y kernels, softirqs are executed in a per-CPU > ksoftirqd thread or in the context of the task that raised the softirq. > This means in_task() can return true even while serving softirqs. This > behavior causes KCOV to incorrectly identify the context, leading to state > corruption and various kcov-related warnings reported by syzbot. I need to digest the remaining email but in_task() should not return on PREEMPT_RT if a softirq is served. Regardless if it happens in ksoftirqd or in the context of the task raised via local_bh_enable(). I will digest this later. Sebastian