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authorJosef Bacik <jbacik@fb.com>2017-12-11 11:36:48 -0500
committerAlexei Starovoitov <ast@kernel.org>2017-12-12 09:02:34 -0800
commit9802d86585db91655c7d1929a4f6bbe0952ea88e (patch)
tree53b334864518dd27b243eafc9ab510ac56ee3b74 /kernel/trace/Kconfig
parent8556e50994c8a8f5282fea008ae084d6d080648a (diff)
bpf: add a bpf_override_function helper
Error injection is sloppy and very ad-hoc. BPF could fill this niche perfectly with it's kprobe functionality. We could make sure errors are only triggered in specific call chains that we care about with very specific situations. Accomplish this with the bpf_override_funciton helper. This will modify the probe'd callers return value to the specified value and set the PC to an override function that simply returns, bypassing the originally probed function. This gives us a nice clean way to implement systematic error injection for all of our code paths. Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/trace/Kconfig')
-rw-r--r--kernel/trace/Kconfig11
1 files changed, 11 insertions, 0 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index af7dad126c13..3e6fd580fe7f 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -529,6 +529,17 @@ config FUNCTION_PROFILER
If in doubt, say N.
+config BPF_KPROBE_OVERRIDE
+ bool "Enable BPF programs to override a kprobed function"
+ depends on BPF_EVENTS
+ depends on KPROBES_ON_FTRACE
+ depends on HAVE_KPROBE_OVERRIDE
+ depends on DYNAMIC_FTRACE_WITH_REGS
+ default n
+ help
+ Allows BPF to override the execution of a probed function and
+ set a different return value. This is used for error injection.
+
config FTRACE_MCOUNT_RECORD
def_bool y
depends on DYNAMIC_FTRACE