Re: Panic: dma_map_area overflow 66 bytes on 3.7+

[Eric Dumazet <eric.dumazet@gmail.com>]

On Fri, 2012-12-28 at 20:05 +0100, Martin Nybo Andersen wrote:
> Hi list,
> 
> Since the release of 3.7 my main computer has been panicking a couple of
> times on both 3.7.0 and 3.7.1 because of a 'dma_map_area overflow xx bytes'.
> 
> Example screen shot:
> http://www.tweek.dk/panic.jpg
> 
> I can reproduce it somewhat easily by visiting http://www.openstreetmap.org/
> and zoom erratically with the scroll-button on the mouse.
> 
> The panic seems to occur on line 229 of arch/x86/kernel/amd_gart_64.c, and
> reverting commit aee77e4accbeb2c86b1d294cd84fec4a12dde3bd (r8169: use
> unlimited DMA burst for TX) seems to fix the problem for me (at least I've
> not been able to make it panic as before (yet)).
> 
> 
> lspci -v:
> 00:00.0 Host bridge: Advanced Micro Devices [AMD] nee ATI RS480 Host Bridge (rev 01)
> 00:02.0 PCI bridge: Advanced Micro Devices [AMD] nee ATI RS480 PCI-X Root Port
> 00:05.0 PCI bridge: Advanced Micro Devices [AMD] nee ATI RS480 PCI Bridge
> 00:12.0 SATA controller: Advanced Micro Devices [AMD] nee ATI SB600 Non-Raid-5 SATA
> 00:13.0 USB controller: Advanced Micro Devices [AMD] nee ATI SB600 USB (OHCI0)
> 00:13.1 USB controller: Advanced Micro Devices [AMD] nee ATI SB600 USB (OHCI1)
> 00:13.2 USB controller: Advanced Micro Devices [AMD] nee ATI SB600 USB (OHCI2)
> 00:13.3 USB controller: Advanced Micro Devices [AMD] nee ATI SB600 USB (OHCI3)
> 00:13.4 USB controller: Advanced Micro Devices [AMD] nee ATI SB600 USB (OHCI4)
> 00:13.5 USB controller: Advanced Micro Devices [AMD] nee ATI SB600 USB Controller (EHCI)
> 00:14.0 SMBus: Advanced Micro Devices [AMD] nee ATI SBx00 SMBus Controller (rev 13)
> 00:14.1 IDE interface: Advanced Micro Devices [AMD] nee ATI SB600 IDE
> 00:14.2 Audio device: Advanced Micro Devices [AMD] nee ATI SBx00 Azalia (Intel HDA)
> 00:14.3 ISA bridge: Advanced Micro Devices [AMD] nee ATI SB600 PCI to LPC Bridge
> 00:14.4 PCI bridge: Advanced Micro Devices [AMD] nee ATI SBx00 PCI to PCI Bridge
> 00:18.0 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] HyperTransport Technology Configuration
> 00:18.1 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Address Map
> 00:18.2 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] DRAM Controller
> 00:18.3 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Miscellaneous Control
> 01:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 01)
> 02:00.0 VGA compatible controller: NVIDIA Corporation G84 [GeForce 8600 GT] (rev a1)
> 03:07.0 Multimedia controller: Twinhan Technology Co. Ltd Mantis DTV PCI Bridge Controller [Ver 1.0] (rev 01)
> 
> 
> Please tell, if more info is needed.

Seems you have CONFIG_IOMMU_DEBUG, is it really what you want ?

It seems a bit strange we panic in this case
( panic_on_overflow = 1;)

You could try to add iommu=nopanic to your boot command : packet should
be dropped, instead of panic.

config IOMMU_DEBUG
        bool "Enable IOMMU debugging"
        depends on GART_IOMMU && DEBUG_KERNEL
        depends on X86_64
        ---help---
          Force the IOMMU to on even when you have less than 4GB of
          memory and add debugging code. On overflow always panic. And
          allow to enable IOMMU leak tracing. Can be disabled at boot
          time with iommu=noforce. This will also enable scatter gather
          list merging.  Currently not recommended for production
          code. When you use it make sure you have a big enough
          IOMMU/AGP aperture.  Most of the options enabled by this can
          be set more finegrained using the iommu= command line
          options. See Documentation/x86/x86_64/boot-options.txt for more
          details.