From: Frederic Weisbecker <fweisbec@gmail.com>
Date: Thu, 31 Dec 2009 02:52:25 +0000 (+0100)
Subject: perf: Stop stack frame walking off kernel addresses boundaries
X-Git-Tag: v2.6.33-rc5~31^2~2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c2c5d45d46c8c0fd34291dec958670ad4816796f;p=pandora-kernel.git

perf: Stop stack frame walking off kernel addresses boundaries

While processing kernel perf callchains, an bad entry can be
considered as a valid stack pointer but not as a kernel address.

In this case, we hang in an endless loop. This can happen in an
x86-32 kernel after processing the last entry in a kernel
stacktrace.

Just stop the stack frame walking after we encounter an invalid
kernel address.

This fixes a hard lockup in x86-32.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1262227945-27014-1-git-send-regression-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

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