Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965325AbVKHAEj (ORCPT ); Mon, 7 Nov 2005 19:04:39 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965341AbVKHAEj (ORCPT ); Mon, 7 Nov 2005 19:04:39 -0500 Received: from mailout1.vmware.com ([65.113.40.130]:50705 "EHLO mailout1.vmware.com") by vger.kernel.org with ESMTP id S965325AbVKHAEi (ORCPT ); Mon, 7 Nov 2005 19:04:38 -0500 Date: Mon, 7 Nov 2005 16:04:34 -0800 Message-Id: <200511080004.jA804Y0Y020472@zach-dev.vmware.com> Subject: [PATCH 1/1] Elevator init fixes From: Zachary Amsden To: Linus Torvalds , Andrew Morton , Linux Kernel Mailing List , Jens Axboe , Tejun Heo , Zachary Amsden X-OriginalArrivalTime: 08 Nov 2005 00:04:37.0450 (UTC) FILETIME=[01FA42A0:01C5E3F8] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1536 Lines: 46 I got a panic in the elevator code, backtrace : Unable to handle kernel NULL pointer dereference at virtual address 00000060 .. EIP is at elevator_put+0x0/0x30 (null elevator_type passed) .. elevator_init+0x38 blk_init_queu_node+0xc9 floppy_init+0xdb do_initcalls+0x23 init+0x10a init+0x0 Clearly if the kmalloc here fails, e->elevator_type is not yet set; this appears to be the correct fix, but I think I probably hit the second case due to a race condition. Someone more familiar with the elevator code should look at this more closely until I can determine if I can reproduce. Signed-off-by: Zachary Amsden Index: linux-2.6.14-zach-work/drivers/block/elevator.c =================================================================== --- linux-2.6.14-zach-work.orig/drivers/block/elevator.c 2005-11-07 09:41:11.000000000 -0800 +++ linux-2.6.14-zach-work/drivers/block/elevator.c 2005-11-07 15:57:10.000000000 -0800 @@ -190,14 +190,14 @@ int elevator_init(request_queue_t *q, ch eq = kmalloc(sizeof(struct elevator_queue), GFP_KERNEL); if (!eq) { - elevator_put(e->elevator_type); + elevator_put(e); return -ENOMEM; } ret = elevator_attach(q, e, eq); if (ret) { kfree(eq); - elevator_put(e->elevator_type); + elevator_put(e); } return ret; - 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/