From: Steven Rostedt Date: Tue, 4 Feb 2014 19:13:15 +0000 (-0500) Subject: x86: Use preempt_disable_notrace() in cycles_2_ns() X-Git-Tag: v3.14-rc3~18^2~3 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=569d6557ab957d6ae7e97a46ae669174be4189e6;p=pandora-kernel.git x86: Use preempt_disable_notrace() in cycles_2_ns() When debug preempt is enabled, preempt_disable() can be traced by function and function graph tracing. There's a place in the function graph tracer that calls trace_clock() which eventually calls cycles_2_ns() outside of the recursion protection. When cycles_2_ns() calls preempt_disable() it gets traced and the graph tracer will go into a recursive loop causing a crash or worse, a triple fault. Simple fix is to use preempt_disable_notrace() in cycles_2_ns, which makes sense because the preempt_disable() tracing may use that code too, and it tracing it, even with recursion protection is rather pointless. Signed-off-by: Steven Rostedt Acked-by: Thomas Gleixner Signed-off-by: Peter Zijlstra Cc: Linus Torvalds Link: http://lkml.kernel.org/r/20140204141315.2a968a72@gandalf.local.home Signed-off-by: Ingo Molnar --- Reading git-diff-tree failed