Re: 3.14-mw regression: rtl8169 WARNING: DMA-API: exceeded 7 overlapping mappings of pfn 55ebe

From: Sander Eikelenboom
Date: Thu Feb 06 2014 - 06:36:46 EST


Hi Dan / Francois,

Didn't have time to test it before, but the patch doesn't seem to help.
I'm still getting the "DMA-API: exceeded 7 overlapping mappings of pfn 55ebe",
but i see now i forgot to mention i use r8169.use_dac=1 ...

Not using it seems to prevent the warning, but before 3.14 i have never seen this (with r8169.use_dac=1)

--
Sander

Wednesday, January 29, 2014, 4:06:24 AM, you wrote:

> On Sun, Jan 26, 2014 at 4:03 PM, Francois Romieu <romieu@xxxxxxxxxxxxx> wrote:
>> Sander Eikelenboom <linux@xxxxxxxxxxxxxx> :
>> [...]
>>> I have got a regression with a 3.14-mw kernel (last commit is 4ba9920e5e9c0e16b5ed24292d45322907bb9035):
>>> It looks like it's related to the rtl8169 ...
>>>
>>> --
>>> Sander
>>>
>>> Jan 26 11:36:26 serveerstertje kernel: [ 89.105537] ------------[ cut here ]------------
>>> Jan 26 11:36:26 serveerstertje kernel: [ 89.116779] WARNING: CPU: 0 PID: 0 at lib/dma-debug.c:491 add_dma_entry+0x103/0x130()
>>> Jan 26 11:36:26 serveerstertje kernel: [ 89.128148] DMA-API: exceeded 7 overlapping mappings of pfn 55ebe
>>> Jan 26 11:36:26 serveerstertje kernel: [ 89.139397] Modules linked in:
>>> Jan 26 11:36:26 serveerstertje kernel: [ 89.150535] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.13.0-20140125-mw-pcireset+ #1
>>> Jan 26 11:36:26 serveerstertje kernel: [ 89.161784] Hardware name: MSI MS-7640/890FXA-GD70 (MS-7640) , BIOS V1.8B1 09/13/2010
>>> Jan 26 11:36:26 serveerstertje kernel: [ 89.172965] 0000000000000009 ffff88005f603838 ffffffff81acbcfa ffffffff822134e0
>>> Jan 26 11:36:26 serveerstertje kernel: [ 89.184156] ffff88005f603888 ffff88005f603878 ffffffff810bdf62 ffff880000000000
>>> Jan 26 11:36:26 serveerstertje kernel: [ 89.195186] 0000000000055ebe 00000000ffffffef 0000000000000200 ffff8800592ea098
>>> Jan 26 11:36:26 serveerstertje kernel: [ 89.206227] Call Trace:
>>> Jan 26 11:36:26 serveerstertje kernel: [ 89.217027] <IRQ> [<ffffffff81acbcfa>] dump_stack+0x46/0x58
>>> Jan 26 11:36:26 serveerstertje kernel: [ 89.227907] [<ffffffff810bdf62>] warn_slowpath_common+0x82/0xb0
>>> Jan 26 11:36:26 serveerstertje kernel: [ 89.238678] [<ffffffff810be031>] warn_slowpath_fmt+0x41/0x50
>>> Jan 26 11:36:26 serveerstertje kernel: [ 89.249336] [<ffffffff81471c5a>] ? active_pfn_read_overlap+0x3a/0x70
>>> Jan 26 11:36:26 serveerstertje kernel: [ 89.259904] [<ffffffff814729e3>] add_dma_entry+0x103/0x130
>>> Jan 26 11:36:26 serveerstertje kernel: [ 89.270416] [<ffffffff81472de6>] debug_dma_map_page+0x126/0x150
>>> Jan 26 11:36:26 serveerstertje kernel: [ 89.280840] [<ffffffff81714686>] rtl8169_start_xmit+0x216/0xa20
>> [r8169 and xen stuff]
>>
>> Dan, I miss the part of the debug code that tells where the mappings were
>> previously set.

> In this case it was a facepalm mistake on my part. The mappings were
> not being properly accounted in the last revision of the patch I sent.
> I copied you on the fix [1].

> --
> Dan

> [1]: http://marc.info/?l=linux-netdev&m=139096447627032&w=2


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