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ARM: fix function graph tracer and unwinder dependencies

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commit 503621628b upstream.

Naresh Kamboju recently reported that the function-graph tracer crashes
on ARM. The function-graph tracer assumes that the kernel is built with
frame pointers.

We explicitly disabled the function-graph tracer when building Thumb2,
since the Thumb2 ABI doesn't have frame pointers.

We recently changed the way the unwinder method was selected, which
seems to have made it more likely that we can end up with the function-
graph tracer enabled but without the kernel built with frame pointers.

Fix up the function graph tracer dependencies so the option is not
available when we have no possibility of having frame pointers, and
adjust the dependencies on the unwinder option to hide the non-frame
pointer unwinder options if the function-graph tracer is enabled.

Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reported-by: Danilo Cezar Zanella <danilo.zanella@iag.usp.br>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Russell King 2019-04-23 17:09:38 +01:00 committed by Greg Kroah-Hartman
parent dc76815698
commit 9fe1460f61
2 changed files with 4 additions and 4 deletions
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2
arch/arm/Kconfig
View file

@ -63,7 +63,7 @@ config ARM
select HAVE_EFFICIENT_UNALIGNED_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && MMU
select HAVE_EXIT_THREAD
select HAVE_FTRACE_MCOUNT_RECORD if (!XIP_KERNEL)
select HAVE_FUNCTION_GRAPH_TRACER if (!THUMB2_KERNEL)
select HAVE_FUNCTION_GRAPH_TRACER if (!THUMB2_KERNEL && !CC_IS_CLANG)
select HAVE_FUNCTION_TRACER if (!XIP_KERNEL)
select HAVE_FUTEX_CMPXCHG if FUTEX
select HAVE_GCC_PLUGINS

6
arch/arm/Kconfig.debug
View file

@ -18,8 +18,8 @@ config ARM_PTDUMP
choice
prompt "Choose kernel unwinder"
default UNWINDER_ARM if AEABI && !FUNCTION_GRAPH_TRACER
default UNWINDER_FRAME_POINTER if !AEABI || FUNCTION_GRAPH_TRACER
default UNWINDER_ARM if AEABI
default UNWINDER_FRAME_POINTER if !AEABI
help
This determines which method will be used for unwinding kernel stack
traces for panics, oopses, bugs, warnings, perf, /proc/<pid>/stack,
@ -36,7 +36,7 @@ config UNWINDER_FRAME_POINTER
config UNWINDER_ARM
bool "ARM EABI stack unwinder"
depends on AEABI
depends on AEABI && !FUNCTION_GRAPH_TRACER
select ARM_UNWIND
help
This option enables stack unwinding support in the kernel