From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with SMTP id AD8F06B02A3 for ; Wed, 14 Jul 2010 04:49:50 -0400 (EDT) Subject: Re: [patch] mm: vmap area cache From: Steven Whitehouse In-Reply-To: <20100701090211.GI22976@laptop> References: <20100531080757.GE9453@laptop> <20100602144905.aa613dec.akpm@linux-foundation.org> <20100603135533.GO6822@laptop> <1277470817.3158.386.camel@localhost.localdomain> <20100626083122.GE29809@laptop> <20100630162602.874ebd2a.akpm@linux-foundation.org> <1277974154.2477.3.camel@localhost> <20100701090211.GI22976@laptop> Content-Type: text/plain; charset="UTF-8" Date: Wed, 14 Jul 2010 09:55:05 +0100 Message-ID: <1279097705.2465.51.camel@localhost> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Nick Piggin Cc: Andrew Morton , Minchan Kim , linux-mm@kvack.org, "Barry J. Marson" , avi@redhat.com List-ID: Hi, During testing of the most recent version of this patch we've hit a kernel bug in alloc_vmap_area(): } 412 BUG_ON(first->va_start < addr); <- Bug triggers here 413 if (addr + cached_hole_size < first->va_start) 414 cached_hole_size = first->va_start - addr; 415 } This appears to be caused by a call from: [] ? kmem_cache_alloc_notrace+0xa0/0xb0 [] ? __get_vm_area_node+0xc5/0x1c0 [] ? walk_system_ram_range+0xa5/0x1c0 [] ? get_vm_area_caller+0x4e/0x60 [] ? intel_opregion_init+0xbc/0x510 [i915] [] ? __ioremap_caller+0x2b0/0x420 [] ? intel_opregion_init+0xbc/0x510 [i915] [] ? ioremap_nocache+0x18/0x20 [] ? intel_opregion_init+0xbc/0x510 [i915] [] ? intel_opregion_init+0xbc/0x510 [i915] [] ? delayed_slow_work_enqueue+0xcc/0xf0 [] ? drm_kms_helper_poll_init+0xc0/0x130 [drm_kms_helper] [] ? i915_driver_load+0x757/0x10c0 [i915] [] ? i915_vga_set_decode+0x0/0x20 [i915] [] ? drm_sysfs_device_add+0x75/0xa0 [drm] [] ? drm_get_dev+0x2b7/0x4c0 [drm] [] ? pci_match_device+0x16/0xc0 [] ? local_pci_probe+0xb/0x10 [] ? pci_device_probe+0x61/0x80 [] ? driver_probe_device+0x87/0x290 etc. So I guess that there might be something odd about that ioremap. It triggers on every boot of the machine in question. It looks to me as if perhaps its found a cached entry which doesn't fit in some way, but I'm not certain of that yet, Steve. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org