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 AAA4A4414; Thu, 8 Jan 2026 15:39:22 +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=1767886762; cv=none; b=OButrIScaJybWSZPDZ7TKru1tolZmE7jvF1JbSJjoZxe2HrmfazQqybFtOpwJGmWQ1WHAE1hOxsfuyPbGkzLIJurflJRnZBMWZ9qFocyctBENcEzawhTyrTMIj+EvG4gV38QPQoJO/A/8kIGWhoDhogK9CZUhUS1ea1A1nVR25U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767886762; c=relaxed/simple; bh=Hi7vs1cUJYiT9la3vecJJWq3lFQhzg7SJsm+svPYA4M=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=SB6gKEVYEB6kqsgPWrVJ7L6Xp9Kir/Hi//yYAK/eEYUDkK1ztXSNfCBl5Gp9P/9Q23grR4a4l4jmOuZwiV4d/fH6joD8Wb4L/IZBoF2P0UdsUuITTBusJJUvmNj2OCh/xYGBjWMew3ccAsBMbSb63fT5VHFAGmpWL0VlTCMvTB8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=PDGsb9Jb; 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="PDGsb9Jb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BED15C116C6; Thu, 8 Jan 2026 15:39:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1767886762; bh=Hi7vs1cUJYiT9la3vecJJWq3lFQhzg7SJsm+svPYA4M=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=PDGsb9JbMj0qv/TN5BPGZEWPOv4AFVm3WeS1ra4btcS56c0+tGVgkUkN4TrfQPHwp qTIui4UBaVzaZ8gHiu9KnRMYGanTwNgff+d0E3XuJr2SCTrx2seJPfdE+z234o6IJh 1GfbzRxx8ERTfw454TifjdGgdXpwpkfw/PvfAWXRVylzION6vl6q9fsrtrW7786qzR 6Gs5uKEkoR/WN8q65Um2KcLOjmh8g3kEuJJ/NawC59R2ECSAsG8qMb2MDqJXApJa36 aK15RtngQ3SZijVYiD5QwYuNirCERLrR3Qh4os00h39rYMC+R90iMlt56lQ1oM88rV m5hShqqSE7wCw== Date: Thu, 8 Jan 2026 16:39:19 +0100 From: Frederic Weisbecker To: Joel Fernandes Cc: Joel Fernandes , Paul E McKenney , Boqun Feng , rcu@vger.kernel.org, Neeraj Upadhyay , Josh Triplett , Uladzislau Rezki , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Shuah Khan , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Kai Yao , Tengda Wu Subject: Re: [PATCH -next 1/8] rcu: Fix rcu_read_unlock() deadloop due to softirq Message-ID: References: <9086EA4F-0393-4E01-AE74-1B428904BFCE@joelfernandes.org> Precedence: bulk X-Mailing-List: rcu@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <9086EA4F-0393-4E01-AE74-1B428904BFCE@joelfernandes.org> Le Wed, Jan 07, 2026 at 10:35:44PM -0500, Joel Fernandes a écrit : > > > > By the way, when I last tried to do it from rcu_qs, it was not fixing the original bug with the IRQ work recursion. > > > > I found that it was always resetting the flag. But probably it is not even the right place to do it in the first place. > > I think we need to reset the flag in rcu_report_exp_rdp() as well if exp_hint > is set and we reported exp qs. To avoid needlessly reaching the rcu_read_unlock() slowpath whenever the exp QS has already been reported, yes indeed. > I am working on a series to cover all cases and will send RFC soon. However this patch we are > reviewing can go in for this merge window and the rest I am preparing (for > further improvement) for the next merge window, if that sounds good. Ok. -- Frederic Weisbecker SUSE Labs