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authorSteven Rostedt (VMware) <rostedt@goodmis.org>2020-01-03 05:56:44 +0300
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2020-01-03 05:56:44 +0300
commitd2ccbccb5444e9141b33cf5399927737e9ff1c3d (patch)
tree242acc9830ad7c3e2e1cc48ffdb3f2eca28b4665 /kernel/trace/fgraph.c
parent02f4e01ce710fe20d2e5548d52bfdea52efd09d1 (diff)
downloadlinux-d2ccbccb5444e9141b33cf5399927737e9ff1c3d.tar.xz
tracing: Define MCOUNT_INSN_SIZE when not defined without direct calls
In order to handle direct calls along side of function graph tracer, a check is made to see if the address being traced by the function graph tracer is a direct call or not. To get the address used by direct callers, the return address is subtracted by MCOUNT_INSN_SIZE. For some archs with certain configurations, MCOUNT_INSN_SIZE is undefined here. But these should not be using direct calls anyway. Just define MCOUNT_INSN_SIZE to zero in this case. Link: https://lore.kernel.org/r/202001020219.zvE3vsty%lkp@intel.com Reported-by: kbuild test robot <lkp@intel.com> Fixes: ff205766dbbee ("ftrace: Fix function_graph tracer interaction with BPF trampoline") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/fgraph.c')
-rw-r--r--kernel/trace/fgraph.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index a2659735db73..1af321dec0f1 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -96,6 +96,20 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func,
return 0;
}
+/*
+ * Not all archs define MCOUNT_INSN_SIZE which is used to look for direct
+ * functions. But those archs currently don't support direct functions
+ * anyway, and ftrace_find_rec_direct() is just a stub for them.
+ * Define MCOUNT_INSN_SIZE to keep those archs compiling.
+ */
+#ifndef MCOUNT_INSN_SIZE
+/* Make sure this only works without direct calls */
+# ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+# error MCOUNT_INSN_SIZE not defined with direct calls enabled
+# endif
+# define MCOUNT_INSN_SIZE 0
+#endif
+
int function_graph_enter(unsigned long ret, unsigned long func,
unsigned long frame_pointer, unsigned long *retp)
{