From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 52D2323536F for ; Thu, 6 Feb 2025 16:56:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738860969; cv=none; b=jwcY9grmwyrOashulwvYyWxw6lIx1ze7YBNIWBjoCH3P5Sx+86GtsvI0cLnGiANwk+H1K1llVzWoWdwpTPZDvsekCq9+afk0eudabQMJQdbWGfyRy3EjhgTvlhII0BanbJO5v4hRcmOU7zOXHVyzt/3SwS+V1rUFpp1xsr5IbGg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738860969; c=relaxed/simple; bh=nRi9kdS8EsQG90TCmLnFALcOEZ/59Y2EQ5JMu4ZEatw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=haHTyRMm71beu6cua5xy8w2im4cY04qB/u0fo/m5eJU5IcMMLJFXwm/uu5JeEYW8H1e3kjLncS4Q5bgoR9T21gZ3i4nLk2nSTBfSAyQ6pArUZCfCCcP6P8nJV7l4o/LX7PjMnfOIs+X0B/00un7WTUQp07d46yYOJqydA/8Lp8w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=CfuBVgS4; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="CfuBVgS4" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1738860966; 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=gU80E8PV5a3vu2ip9PK9xHtZXsnxVCi/FTxDWOZyx3E=; b=CfuBVgS4mq6AxrPmp1PTsb+9aRnhXlDpihRssmMb+OmHrfqD+76vXK+6cy8l3jJgX1ww2n QiiLZnjaJJwSyAWKvsZBMorZsyZb+Y60GYgeN6SpdV1ufJKkLD7D09xmdzCSNiRi0M9By+ CgD+0uTDKmnegp7HSBw33OnDjY9QspY= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-146-0MEF2YimMoKBRT07KNiYfw-1; Thu, 06 Feb 2025 11:56:02 -0500 X-MC-Unique: 0MEF2YimMoKBRT07KNiYfw-1 X-Mimecast-MFC-AGG-ID: 0MEF2YimMoKBRT07KNiYfw Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 1B2F219560B1; Thu, 6 Feb 2025 16:56:00 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.44.34.53]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id 8099A1955BD4; Thu, 6 Feb 2025 16:55:56 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Thu, 6 Feb 2025 17:55:33 +0100 (CET) Date: Thu, 6 Feb 2025 17:55:28 +0100 From: Oleg Nesterov To: Frederic Weisbecker Cc: Andrew Morton , "Eric W. Biederman" , Peter Zijlstra , Thomas Gleixner , Mateusz Guzik , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/2] exit: change the release_task() paths to call flush_sigqueue() lockless Message-ID: <20250206165527.GD5209@redhat.com> References: <20250206152244.GA14609@redhat.com> <20250206152314.GA14620@redhat.com> 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=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 On 02/06, Frederic Weisbecker wrote: > > > TODO: > > - we can probably shift posix_cpu_timers_exit() as well > > Hmm, can't a timer be concurrently deleted between __exit_signal() set > tsk->sighand = NULL and release sighand lock, and the actual call to > posix_cpu_timer_exit() ? And then posix_cpu_timer_exit() calls timerqueue_del() > on a node that don't exist anymore? Can't answer right now, I will think about it when/if I will actually try to make this change ;) This "TODO" note just tries to explain what else we could try to do, and "probably" means that I am not sure yet. I can remove this spam from the changelog, but I'd prefer to keep it as a reminder, at least for myself. > Reviewed-by: Frederic Weisbecker Thanks Frederic! Oleg.