Chunyan Zhang 2b9743441a arm64: use preempt_disable_notrace in _percpu_read/write ... When debug preempt or preempt tracer is enabled, preempt_count_add/sub() can be traced by function and function graph tracing, and preempt_disable/enable() would call preempt_count_add/sub(), so in Ftrace subsystem we should use preempt_disable/enable_notrace instead. In the commit 345ddcc882 ("ftrace: Have set_ftrace_pid use the bitmap like events do") the function this_cpu_read() was added to trace_graph_entry(), and if this_cpu_read() calls preempt_disable(), graph tracer will go into a recursive loop, even if the tracing_on is disabled. So this patch change to use preempt_enable/disable_notrace instead in this_cpu_read(). Since Yonghui Yang helped a lot to find the root cause of this problem, so also add his SOB. Signed-off-by: Yonghui Yang <mark.yang@spreadtrum.com> Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>		2016-09-09 12:34:47 +01:00
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asm	arm64: use preempt_disable_notrace in _percpu_read/write	2016-09-09 12:34:47 +01:00
uapi/asm	arm64 fixes:	2016-08-06 08:58:59 -04:00