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 528BF1E493C for ; Thu, 20 Feb 2025 07:14:07 +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=1740035648; cv=none; b=Emu7Mrg4eVu/H1b/Yzs0VncFsCm6JmrDd2+zz4Ryg6KAB/WNydS7PpTIYRydVmoqOZJ0esLU+ISen5F8MTLcochxHZhhzdpWoI8XiXIoyGRLVXxjtH9z4LlAAA9PjEqZo8vOr6XrWgIgTUyAhHGkRXfzbgkjsaMf38AyhISYPDo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740035648; c=relaxed/simple; bh=dslbUWrrsVEiz8BClDYjVHsCRYq2aWUj0d7gMWiKElc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=r80PAWdvNOS99KUsN1GN0nSPDo20Fc8iLoGmZ/ntAIX4qzly1IRjWUG8dsqouo5eGCZLm0M17Teda+AFZ9A/zqyrujGZaVQYWuuKzSHnu5EST7ncM8oPwdJA6YmZFHTNOYsLeor6yzPjdWvPI9gGni01IGxUUy5XG29k9pS57tY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Nhhnr8LT; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Nhhnr8LT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F094C4CED1; Thu, 20 Feb 2025 07:14:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1740035647; bh=dslbUWrrsVEiz8BClDYjVHsCRYq2aWUj0d7gMWiKElc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Nhhnr8LTnY26chfBq1HI+syrTJKxnbOmyyhEMpgHzE4Ph3AxnKGxL4N+kc4Mh4MlX BRpDIeFSGqyR+ab4vvMRvnZtkkTU7O1FoGuEDdNIjpwsjRcm2GR9lTMqjEwH5iOizC jTGUtHsBpfPoxrk2IIHUciR7K3Opr01EM2NdVkxo= Date: Thu, 20 Feb 2025 08:13:00 +0100 From: Greg Kroah-Hartman To: Dmitry Torokhov Cc: "Rafael J. Wysocki" , Danilo Krummrich , linux-kernel@vger.kernel.org, "Masami Hiramatsu (Google)" , Dirk Behme Subject: Re: [PATCH 1/2] Revert "drivers: core: synchronize really_probe() and dev_uevent()" Message-ID: <2025022051-happy-plant-b40b@gregkh> References: <20250220064647.2437048-1-dmitry.torokhov@gmail.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: <20250220064647.2437048-1-dmitry.torokhov@gmail.com> On Wed, Feb 19, 2025 at 10:46:44PM -0800, Dmitry Torokhov wrote: > This reverts commit c0a40097f0bc81deafc15f9195d1fb54595cd6d0. > > Probing a device can take arbitrary long time. In the field we observed > that, for example, probing a bad micro-SD cards in an external USB card > reader (or maybe cards were good but cables were flaky) sometimes takes > longer than 2 minutes due to multiple retries at various levels of the > stack. We can not block uevent_show() method for that long because udev > is reading that attribute very often and that blocks udev and interferes > with booting of the system. > > The change that introduced locking was concerned with dev_uevent() > racing with unbinding the driver. However we can handle it without > locking (which will be done in subsequent patch). So shouldn't we take the second patch first to prevent any issues here? > There was also claim that synchronization with probe() is needed to > properly load USB drivers, however this is a red herring: the change > adding the lock was introduced in May of last year and USB loading and > probing worked properly for many years before that. > > Revert the harmful locking. > > Signed-off-by: Dmitry Torokhov No Fixes: or cc: stable for this? thanks, greg k-h