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authorJames Morse <james.morse@arm.com>2016-04-28 16:18:52 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-04-28 19:34:04 -0700
commitbdab42dfc974d15303afbf259f340f374a453974 (patch)
tree92cfc8967934a0ff318d176351599a20bcb1004f /kernel/kcov.c
parentfd901c95388b3bd5a6f749ed1d677a672b992298 (diff)
downloadlwn-bdab42dfc974d15303afbf259f340f374a453974.tar.gz
lwn-bdab42dfc974d15303afbf259f340f374a453974.zip
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: James Morse <james.morse@arm.com> Acked-by: Dmitry Vyukov <dvyukov@google.com> Cc: Alexander Potapenko <glider@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/kcov.c')
-rw-r--r--kernel/kcov.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/kcov.c b/kernel/kcov.c
index 3efbee0834a8..78bed7125515 100644
--- a/kernel/kcov.c
+++ b/kernel/kcov.c
@@ -43,7 +43,7 @@ struct kcov {
* Entry point from instrumented code.
* 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;
enum kcov_mode mode;