To: linux-kernel@vger.kernel.org
From: "lkml@tigusoft.pl" <lkml@tigusoft.pl>
Subject: bug? 3.2.43 hangs some tasks after network unplugged, maybe related
 to kvm
Date: Mon, 29 Apr 2013 13:26:48 +0200
Organization: tigusoft.pl
Message-ID: <kllldq$j61$1@ger.gmane.org>
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Kernel: 3.2.43, with grsecurity security patch (with most options except
blocking kmem and ioport access) on 8 core amd cpu, 8 gb ram.

In tty1 I logged into root, then su into another user (uid=1001).

In bash, when I typed "dme" and pressed TAB to auto complete, it hanged.
Now the text cursor just blinks there, pressing anything line ctrl+C
does nothing. Going to tty2 and back works (but does not unhang the bash).

This bash process shows up as "S+" state in ps aux.
Attaching strace -p into it resulted in the strace hanging too, after
writting Process 4936 attached - interrupt to quit (ctrl+C does nothing).

A moment before the hang occured (2-3 seconds) the ethernet cable was
unplugged.
There where bridges (br, tun/tap) configured because there where kvm
machines running (one machine, kvm3) and few other where stopped.

Maybe that was related to recent 3.2.43 kvm exploits/corruptions in some
way.

The kernel has overall normal debian configuration, except it was
configured for lowest latency (low latency desktop) and afiar had more
HZ ticks (1000?).


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