Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754872Ab3DLUpA (ORCPT ); Fri, 12 Apr 2013 16:45:00 -0400 Received: from mail.digidescorp.com ([50.73.98.161]:35583 "EHLO mail.digidescorp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751504Ab3DLUo7 (ORCPT ); Fri, 12 Apr 2013 16:44:59 -0400 X-MDAV-Processed: mail.digidescorp.com, Fri, 12 Apr 2013 15:44:58 -0500 X-Spam-Processed: mail.digidescorp.com, Fri, 12 Apr 2013 15:44:57 -0500 (not processed: message from trusted or authenticated source) X-Authenticated-Sender: steve@digidescorp.com X-Return-Path: smagnani@iscandar.digidescorp.com X-Envelope-From: smagnani@iscandar.digidescorp.com X-MDaemon-Deliver-To: linux-kernel@vger.kernel.org From: Steve Magnani To: "James E.J. Bottomley" Cc: Tejun Heo , linux-kernel@vger.kernel.org, "Steven J. Magnani" Subject: [PATCH] sd: fix infinite kernel/udev loop on non-removable Medium Not Present Date: Fri, 12 Apr 2013 15:44:48 -0500 Message-Id: <1365799488-16088-1-git-send-email-smagnani@iscandar.digidescorp.com> X-Mailer: git-send-email 1.8.1.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1635 Lines: 40 Commit eface65c336eff420d70beb0fb6787a732e05ffb (2.6.38) altered set_media_not_present() in a way that prevents the sd driver from remembering that a non-removable device has reported "Medium Not Present". This condition can occur on hotplug of a (i.e.) USB Mass Storage device whose medium is offline due to an unrecoverable controller error, but which is otherwise capable of SCSI communication (to download new microcode, etc.). Under these conditions, the changed code results in an infinite loop between the kernel and udevd. When udevd attempts to open the device in response to a change notification, a SCSI "Medium Not Present" error occurs which causes the kernel to signal another change. The cycle repeats until the device is unplugged, resulting in udevd consuming ever- increasing amounts of CPU and virtual memory. Resolve this by remembering "media not present" whether the device has declared itself "removable" or not. Signed-off-by: Steven J. Magnani --- --- a/drivers/scsi/sd.c 2013-04-12 14:16:12.252531097 -0500 +++ b/drivers/scsi/sd.c 2013-04-12 14:21:55.197216521 -0500 @@ -1298,10 +1298,8 @@ out: static void set_media_not_present(struct scsi_disk *sdkp) { - if (sdkp->media_present) + if (sdkp->media_present) { sdkp->device->changed = 1; - - if (sdkp->device->removable) { sdkp->media_present = 0; sdkp->capacity = 0; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/