From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46370) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1g9q0W-0000ku-P9 for qemu-devel@nongnu.org; Tue, 09 Oct 2018 07:16:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1g9q0V-00006h-CI for qemu-devel@nongnu.org; Tue, 09 Oct 2018 07:16:56 -0400 References: <20181005143802.18412-1-peter.maydell@linaro.org> <20181005161739.GC4606@localhost.localdomain> <20181005180901.GA32677@localhost.localdomain> <20181008164026.GD4604@localhost.localdomain> From: Paolo Bonzini Message-ID: Date: Tue, 9 Oct 2018 13:16:16 +0200 MIME-Version: 1.0 In-Reply-To: <20181008164026.GD4604@localhost.localdomain> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] tests: Disable test-bdrv-drain List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf , Peter Maydell Cc: QEMU Developers , Max Reitz , Qemu-block , "patches@linaro.org" On 08/10/2018 18:40, Kevin Wolf wrote: >> >> I'm pretty confident this analysis of the problem is correct: >> unfortunately I have no idea what the right way to fix it is... > Yes, I agree with your analysis. If __thread variables can be destructed > before pthread_key_create() destructors are called (and in particular if > the former are implemented in terms of the latter), this implies at > least two rules: > > 1. The Notfier itself can't be a TLS variable > > 2. The notifier callback can't access any TLS variables > > Of course, with these restrictions, qemu_thread_atexit_*() with its > existing API is as useless as it could be. Yup, we have to stop using pthread_key_create. Luckily, these days there is always qemu_thread_start that wraps the thread, so we can call qemu_thread_atexit_run from there, and change exit_key to a thread-local NotifierList. Paolo