Messages in this thread | | | Date | Fri, 11 Jan 2019 18:01:39 -0700 | From | Jeremy Fertic <> | Subject | ARM: config issue with ftrace function graph tracer |
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I'm having a problem with the ftrace function graph tracer on a 32 bit arm board (orangepi pc). A bisect points to the following commit:
f9b58e8c7d03 ("ARM: 8800/1: use choice for kernel unwinders")
Before this commit, if I use sunxi_defconfig and then menuconfig to enable FTRACE and FUNCTION_TRACER then the function graph tracer works. With this commit, and as of v5.0-rc1, doing the same as above results in a broken function graph tracer and often an oops as well. The commit introduces a choice group and it looks like it should default to UNWINDER_FRAME_POINTER if FUNCTION_GRAPH_TRACER is enabled. FUNCTION_GRAPH_TRACER is enabled by default when I enable FUNCTION_TRACER but this has no effect on the choice. The choice always defaults to the other option which is UNWINDER_ARM. If I manually choose UNWINDER_FRAME_POINTER then the function graph tracer works fine.
Any idea why the default behaviour has changed?
Thanks, Jeremy
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