From: Heiko Carstens Date: Fri, 14 Nov 2008 17:18:05 +0000 (+0100) Subject: [S390] ftrace: fix kernel stack backchain walking X-Git-Tag: v2.6.28-rc5~8^2~4 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=50bec4ce5d36ebf96189dcc54e20c7fce4bf61bf;p=pandora-kernel.git [S390] ftrace: fix kernel stack backchain walking With CONFIG_IRQSOFF_TRACER the trace_hardirqs_off() function includes a call to __builtin_return_address(1). But we calltrace_hardirqs_off() from early entry code. There we have just a single stack frame. So this results in a kernel stack backchain walk that would walk beyond the kernel stack. Following the NULL terminated backchain this results in a lowcore read access. To fix this we simply call trace_hardirqs_off_caller() and pass the current instruction pointer. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- Reading git-diff-tree failed