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<b><a class="bz_bug_link
bz_status_NEEDINFO "
title="NEEDINFO --- - [IVB/HSW ULT]system hang when run nightly testing"
href="https://bugs.freedesktop.org/show_bug.cgi?id=68171#c9">Comment # 9</a>
on <a class="bz_bug_link
bz_status_NEEDINFO "
title="NEEDINFO --- - [IVB/HSW ULT]system hang when run nightly testing"
href="https://bugs.freedesktop.org/show_bug.cgi?id=68171">bug 68171</a>
from <span class="vcard"><a class="email" href="mailto:ben@bwidawsk.net" title="Ben Widawsky <ben@bwidawsk.net>"> <span class="fn">Ben Widawsky</span></a>
</span></b>
<pre>(In reply to <a href="show_bug.cgi?id=68171#c6">comment #6</a>)
<span class="quote">> I dug a bit. It looks to me the failure is that pages is null here:
>
> if (!obj->has_dma_mapping)
> dma_unmap_sg(&dev->pdev->dev,
> obj->pages->sgl, obj->pages->nents,
> PCI_DMA_BIDIRECTIONAL);
>
>
> My disasm is a bit too complex to make sense out of at this hour.</span >
I couldn't believe it before, but I did more digging, it seems to fail on:
obj->pages->nents, which at least on my compiled obj is done first.
218a0: 49 8b 84 24 08 01 00 mov 0x108(%r12),%rax obj->pages
218a7: 00
218a8: 8b 50 08 mov 0x8(%rax),%edx obj->pages->nents
218ab: 48 8b 30 mov (%rax),%rsi
218ae: 49 8b 85 90 04 00 00 mov 0x490(%r13),%rax // dev->pdev
218b5: 48 89 c7 mov %rax,%rdi
218b8: 48 81 c7 98 00 00 00 add $0x98,%rdi //pdev->dev
(In reply to <a href="show_bug.cgi?id=68171#c6">comment #6</a>)</pre>
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