Re: bisected regression: 3c59x corrupts packets in 3.17-rc5

From: Meelis Roos
Date: Tue Sep 16 2014 - 06:32:41 EST


[ Fixed Steffen Klasserts bouncing email address as per the bounce message ]

> > Somewhere between 3.17.0-rc3 and 3.17.0-rc5 I started seeing dropped ssh
> > connections to a couple of test servers with dual AthlonMP (32-bit) and
> > 3C90x family of NICs (3Com Corporation 3c980-C 10/100baseTX NIC
> > [Python-T] (rev 78) in one server and 3Com Corporation 3c905C-TX/TX-M
> > [Tornado] (rev 78) in the other server). Bisect leads to the following
> > commit:
> >
> > 98ea232cf63961fad734cc8c5e07e8915ec73073 is the first bad commit
> > commit 98ea232cf63961fad734cc8c5e07e8915ec73073
> > Author: Neil Horman <nhorman@xxxxxxxxxxxxx>
> > Date: Thu Sep 4 06:13:38 2014 -0400
> >
> > 3c59x: avoid panic in boomerang_start_xmit when finding page address:
> > ...
> >
> I'm guessing the above change has uncovered another bug, mostly likely an
> exhaustion of dma space on your system. Nothing in the transmit path there does
> any error checking for successful dma mapping, which it really should. I'd be
> willing to be that any dma mapping error leads to a leak in the mapping table.
> Does your system have an iommu, or does it use swiotlb? If its the latter, can
> you increase the swiotlb table space and see if that relieves the problem? In
> the interim, I'll start adding some error checking to the transmit path.

# CONFIG_IOMMU_SUPPORT is not set

nothing matching iommu or iotlb in dmesg. I thought the system does not
have any - K7 CPUs and AMD 760MP chipset with normal AGP gart.

[ 3.763519] agpgart-amdk7 0000:00:00.0: AMD 760MP chipset
[ 3.782995] agpgart-amdk7 0000:00:00.0: AGP aperture is 64M @ 0xf8000000

--
Meelis Roos (mroos@xxxxxxxx)
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