netdev - Re: Re: Re: Re: [bisected regression] e1000e: "Detected Hardware Unit Hang"

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1837410.pEGIH05mML@storm>
Date:	Thu, 15 Jan 2015 18:04:06 +0100
From:	Thomas Jarosch <thomas.jarosch@...ra2net.com>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	'Linux Netdev List' <netdev@...r.kernel.org>,
	Eric Dumazet <edumazet@...gle.com>,
	Jeff Kirsher <jeffrey.t.kirsher@...el.com>,
	e1000-devel <e1000-devel@...ts.sourceforge.net>
Subject: Re: Re: Re: Re: [bisected regression] e1000e: "Detected Hardware Unit Hang"

On Thursday, 15. January 2015 08:00:58 Eric Dumazet wrote:
> Please apply this patch, and try to lower
> /proc/sys/net/core/gro_max_frags and see if this makes a difference
> (leaving GRO enabled)
> 
> (start with 7 and increase it, limit being 17)

Patch applied to 3.19-rc4+.

Results:
 7: hang
 8: hang
 9: hang
10: hang
11: hang
12: hang
13: hang
14: hang
15: hang
16: hang
17: hang

for the sake of completeness:
1: hang
2: hang
3: hang
4: hang
5: hang
6: hang

Regarding the test procedure: I stopped the download script on the client,
changed gro_max_frags and started the download again. No cable unplugging / 
reboot of the box in between. Just mentioning it to make sure it somehow 
does not affect what we actually wanted to test.

Additional tests have been done with gro_max_frags 1, 7 and 17:
- stop networking + unload e1000e -> restart -> download: hang

One thing I can say from the testing: The more I increase gro_max_frags,
the longer it takes to trigger it. I tried each setting below three times.
A value of 17 is really noticeable.

1: 3-8 seconds till hang
7: 7-10 seconds till hang
17: 23-26 seconds till hang

Thomas

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html