Commit bdab42df authored by James Morse's avatar James Morse Committed by Linus Torvalds

kcov: don't trace the code coverage code

Kcov causes the compiler to add a call to __sanitizer_cov_trace_pc() in
every basic block.  Ftrace patches in a call to _mcount() to each
function it has annotated.

Letting these mechanisms annotate each other is a bad thing.  Break the
loop by adding 'notrace' to __sanitizer_cov_trace_pc() so that ftrace
won't try to patch this code.

This patch lets arm64 with KCOV and STACK_TRACER boot.
Signed-off-by: default avatarJames Morse <>
Acked-by: default avatarDmitry Vyukov <>
Cc: Alexander Potapenko <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent fd901c95
...@@ -43,7 +43,7 @@ struct kcov { ...@@ -43,7 +43,7 @@ struct kcov {
* Entry point from instrumented code. * Entry point from instrumented code.
* This is called once per basic-block/edge. * This is called once per basic-block/edge.
*/ */
void __sanitizer_cov_trace_pc(void) void notrace __sanitizer_cov_trace_pc(void)
{ {
struct task_struct *t; struct task_struct *t;
enum kcov_mode mode; enum kcov_mode mode;
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