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 846AB369D5D; Sat, 8 Aug 2026 11:23:45 +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=1786188226; cv=none; b=auGy+vYv6l1UvgLhAEsAcVRENcQUf2lmIoNF4F9KCHSMVVziAwe5JKD4oCRSBKcTlYl34JfXG6sbxag+4cMWnbirL8vHuuvyYZ5Psnw5M7uP0cMhY0JV/xMg9JEELPICpcWe1UiO/M5EXt2azD6PkoJ06WRaUMfKXDOTYzff2e8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786188226; c=relaxed/simple; bh=t83XxTkYTjIOO8gk5EYnE5v/WeaiHDzBrlEPozDz5GA=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=ouzAV/Jwgnmm+ZKr10ubgtA/i5aa7c8EsLwBQYercH/NpE+2P6qlB+GaYEnS2BEdn/MV8km3AoJTDaYWh3pIhIPYlAiLriihQNPK5V46JULwL5lH8y025DjskqKT70ag3BTGbdPFuDy1r2l4pRixDzFH2Jmx2Ua2bhjUbWFR6p4= 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=YwbVDrRa; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=eRAl0Ivr; 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="YwbVDrRa"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="eRAl0Ivr" From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1786188223; 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=eENa2wl4a8MYKhB/4KEH1dwTgDpPYzt/9ynYTC1Kg6o=; b=YwbVDrRa31NARv5QOjUwxUmbv0PMBSXa82fHsTTJX4rBWuYVQcteB2LNHGy8nXny4D88Sg DeZWFLcugmxCOGiYxZJNAYsehB6lgE1ObiRwQrzgpfwZnaO85LmifX9SqvRyNCwj4BL1it h8xUqwtjZwdrO2EhEvFd4PjwwC6AZCzZDd1cyvDjTlQrXCDSn50ANf6KfHzCfEkNbbpLjW Q1ekdAGb+7QWWbio5Wk2Od95ZtIp6x5SDbKY2ZrRQAa4jvSSUBJ+bWyuVrtQ0pnWt/JZn/ m00TguhJR2f0EHDNA5CTs8gE3MKTTvPe8UnAKB+PS520vbltRaJuinSKAVkihQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1786188223; 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=eENa2wl4a8MYKhB/4KEH1dwTgDpPYzt/9ynYTC1Kg6o=; b=eRAl0IvrZwIxsHnlY52pGt5E48NWVUn9ZYQkAVbmojSjebV67JDeIMoZ/UPS++zN77zHT9 1UaQ1D4UusjsulBw== To: Peter Zijlstra Cc: tip-bot2 for Niels Pressel , linux-tip-commits@vger.kernel.org, Niels Pressel , x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [tip: core/urgent] entry/rseq: Fix hard lockup on granted time slice extension In-Reply-To: <20260808083635.GR687043@noisy.programming.kicks-ass.net> References: <20260806113429.38333-1-npressel@ethz.ch> <178602048581.708.11608729612787939146.tip-bot2@tip-bot2> <87y0ehmy3c.ffs@fw13> <20260808083635.GR687043@noisy.programming.kicks-ass.net> Date: Sat, 08 Aug 2026 13:23:42 +0200 Message-ID: <87se4on9dt.ffs@fw13> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Sat, Aug 08 2026 at 10:36, Peter Zijlstra wrote: > On Fri, Aug 07, 2026 at 11:15:19PM +0200, Thomas Gleixner wrote: >> rseq = curr->rseq.usrptr; >> scoped_user_rw_access(rseq, efault) { >> >> That's user access which requires interrupts to be enabled. > > Well, you can do user access with IRQs disabled just fine, you just get > more efault. Sure, but then you need a manual fault handler, which requires that interrupts are enabled :) >> So the thing [wm]e f*cked up royally was to invoke >> hrtimer_rearm_deferred_tif() with interrupts enabled and that needs to >> be fixed. >> >> Of course all of this can be figured out from the copious amount of >> comments which got added to explain all of this magic. > > Bah, its spread out over too damn many functions is what :/ That and comments are missing at crucial places :(