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From: Steven Whitehouse <swhiteho@redhat.com>
To: Nick Piggin <npiggin@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Minchan Kim <minchan.kim@gmail.com>,
	linux-mm@kvack.org, "Barry J. Marson" <bmarson@redhat.com>,
	avi@redhat.com
Subject: Re: [patch] mm: vmap area cache
Date: Wed, 14 Jul 2010 09:55:05 +0100	[thread overview]
Message-ID: <1279097705.2465.51.camel@localhost> (raw)
In-Reply-To: <20100701090211.GI22976@laptop>

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:

[<c050f870>] ? kmem_cache_alloc_notrace+0xa0/0xb0                
[<c0503695>] ? __get_vm_area_node+0xc5/0x1c0                     
[<c0458625>] ? walk_system_ram_range+0xa5/0x1c0                  
[<c050383e>] ? get_vm_area_caller+0x4e/0x60                      
[<f827328c>] ? intel_opregion_init+0xbc/0x510 [i915]             
[<c0430ce0>] ? __ioremap_caller+0x2b0/0x420                      
[<f827328c>] ? intel_opregion_init+0xbc/0x510 [i915]             
[<c0430f98>] ? ioremap_nocache+0x18/0x20                         
[<f827328c>] ? intel_opregion_init+0xbc/0x510 [i915]             
[<f827328c>] ? intel_opregion_init+0xbc/0x510 [i915]
[<c04cdc7c>] ? delayed_slow_work_enqueue+0xcc/0xf0               
[<f80f7c20>] ? drm_kms_helper_poll_init+0xc0/0x130 [drm_kms_helper]
[<f8248ec7>] ? i915_driver_load+0x757/0x10c0 [i915]              
[<f82471b0>] ? i915_vga_set_decode+0x0/0x20 [i915]               
[<f81c5675>] ? drm_sysfs_device_add+0x75/0xa0 [drm]              
[<f81c33d7>] ? drm_get_dev+0x2b7/0x4c0 [drm]                     
[<c05f6986>] ? pci_match_device+0x16/0xc0                        
[<c05f68ab>] ? local_pci_probe+0xb/0x10                          
[<c05f76b1>] ? pci_device_probe+0x61/0x80                        
[<c06a34f7>] ? 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.


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      reply	other threads:[~2010-07-14  8:49 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-05-31  8:07 [patch] mm: vmap area cache Nick Piggin
2010-05-31 13:21 ` Minchan Kim
2010-06-02 21:49 ` Andrew Morton
2010-06-03 13:55   ` Nick Piggin
2010-06-25 13:00     ` Steven Whitehouse
2010-06-26  8:31       ` Nick Piggin
2010-06-28  8:37         ` Steven Whitehouse
2010-06-28  8:45           ` Nick Piggin
2010-06-28  9:05             ` Steven Whitehouse
2010-06-30 23:26         ` Andrew Morton
2010-07-01  7:50           ` Nick Piggin
2010-07-01  8:49           ` Steven Whitehouse
2010-07-01  9:02             ` Nick Piggin
2010-07-14  8:55               ` Steven Whitehouse [this message]

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