From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id F2BC0CD4F27 for ; Fri, 22 Sep 2023 07:40:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Date:Cc:To:From:Subject:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=wujLnuGGOV+hr/FYQcU3ubS3yJgj0aQkOg7pSYBvyLo=; b=QTkkc2gyGvIKyI D0Ebpt+JXZ9p0998Aqg27jI6gUmh+rGljdorQtMiQ0RSG4U6/RMUWCJk5LA5QXgDnpxR8BPnygt/7 DbaGGgK4n7GCVOTtTf/9qj8FheJGMdCLnmkSWeE/O3A1JhAyFBRPlyb+zQYLKAAK/rnWDL+NnEezs lmD5dCkccH9WgWu8XEgRhsWno99B4hpFMIO7AttUVJR4/zbpGzVXDdTX8EJlEpQ3r11NDDBpokzXK hAfqWQLWDOfR7AzNetPu+bijK3kGqX8tJU4mcQajfoj/j5kU5C4oWKUlU2NYXG+sGV50Pg5b9hp6b q2WrOWf8X2+Xy5hQxzLQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qjamZ-008DuY-2H; Fri, 22 Sep 2023 07:40:59 +0000 Received: from s3.sipsolutions.net ([2a01:4f8:242:246e::2] helo=sipsolutions.net) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qjamW-008Dtd-1d for linux-um@lists.infradead.org; Fri, 22 Sep 2023 07:40:57 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sipsolutions.net; s=mail; h=MIME-Version:Content-Transfer-Encoding: Content-Type:References:In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-To: Resent-Cc:Resent-Message-ID; bh=97AG6plwjbYaEhkLqaFMdfr/BHNUH5wUgH7ftHRicsk=; t=1695368456; x=1696578056; b=WwdAF3UZMB++Zr5REcYoMrwQslBLr3n8NwVjwCkiLzmcAr6 CO89XtxbGtXr+fHgFSycz4TmX8ZzItsgVUMDwAmgVRyjARNp/dU3yeIkhnFVgJdWB7wXOD3bbN6YA dKKJczGdms3nFzBSrnH8PxlRD4H1kWKJ0G01RmjDN2vBfD1mM2oZk8cbPrGOwOBOswa/REKHTzrJ4 RdQqqqlZM58dWZqpdGGms553BGgxrqslOBmVvvc7QK8NH9j58DbOqQs9pbl0aARfpdLFQChwuh2jw 3b2EJkwGCo+sVdY6DzXm3+u+VTqPG9E1aUohqwJF2/L9Ljsb4PJcnEiq/9dXYP5w==; Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.96) (envelope-from ) id 1qjamU-00Ezla-01; Fri, 22 Sep 2023 09:40:54 +0200 Message-ID: <2de07f54b33dc060b75d982d4d8189f12e0d4c45.camel@sipsolutions.net> Subject: Re: [PATCH v5] um: Enable preemption in UML From: Johannes Berg To: Anton Ivanov , linux-um@lists.infradead.org Cc: richard@nod.at Date: Fri, 22 Sep 2023 09:40:53 +0200 In-Reply-To: References: <20230922065212.484385-1-anton.ivanov@cambridgegreys.com> User-Agent: Evolution 3.48.4 (3.48.4-1.fc38) MIME-Version: 1.0 X-malware-bazaar: not-scanned X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230922_004056_541643_6709E74C X-CRM114-Status: GOOD ( 16.14 ) X-BeenThere: linux-um@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-um" Errors-To: linux-um-bounces+linux-um=archiver.kernel.org@lists.infradead.org On Fri, 2023-09-22 at 08:38 +0100, Anton Ivanov wrote: > > > > I had enabled CONFIG_DEBUG_ATOMIC_SLEEP because that's actually > > something I'd really like to have in our testing. > > > > But with that issue I don't even know how we get there really. It > > doesn't even happen every time we fork? > > > > I'll dig a little bit, but did you try enabling > > CONFIG_DEBUG_ATOMIC_SLEEP also? > > Will do. I have no crashes over here so I need to trigger this one first. > > Though, frankly, if it is a race in a tlb flush it may be subject to local conditions. So it will be difficult to reproduce. > Yes, it might be a race in the fork handler maybe? IOW, whenever we actually do fork, it depends on what conditions the rest is in? I'm not sure I fully figured out right now how the fork handler is doing all this, but I sent my mail before I could since you were discussing :) But it shouldn't be impossible - while I don't see it for every fork, it does happen 8 or 9 times in a very simple test that just boots, pings a bit, and then shuts down, so ... johannes _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um