4.19-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 903e8ff86753e6f327bb92166a0665e4ecb8e2e7 ]
Since __sanitizer_cov_trace_pc() is marked as notrace, function calls in __sanitizer_cov_trace_pc() shouldn't be traced either. ftrace_graph_caller() gets called for each function that isn't marked 'notrace', like canonicalize_ip(). This is the call trace from a run:
[ 139.644550] ftrace_graph_caller+0x1c/0x24 [ 139.648352] canonicalize_ip+0x18/0x28 [ 139.652313] __sanitizer_cov_trace_pc+0x14/0x58 [ 139.656184] sched_clock+0x34/0x1e8 [ 139.659759] trace_clock_local+0x40/0x88 [ 139.663722] ftrace_push_return_trace+0x8c/0x1f0 [ 139.667767] prepare_ftrace_return+0xa8/0x100 [ 139.671709] ftrace_graph_caller+0x1c/0x24
Rework so that check_kcov_mode() and canonicalize_ip() that are called from __sanitizer_cov_trace_pc() are also marked as notrace.
Link: http://lkml.kernel.org/r/20181128081239.18317-1-anders.roxell@linaro.org Signed-off-by: Arnd Bergmann arnd@arndb.de Signen-off-by: Anders Roxell anders.roxell@linaro.org Co-developed-by: Arnd Bergmann arnd@arndb.de Acked-by: Steven Rostedt (VMware) rostedt@goodmis.org Cc: Dmitry Vyukov dvyukov@google.com Cc: Ingo Molnar mingo@elte.hu Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/kcov.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/kcov.c b/kernel/kcov.c index 3ebd09efe72a..97959d7b77e2 100644 --- a/kernel/kcov.c +++ b/kernel/kcov.c @@ -56,7 +56,7 @@ struct kcov { struct task_struct *t; };
-static bool check_kcov_mode(enum kcov_mode needed_mode, struct task_struct *t) +static notrace bool check_kcov_mode(enum kcov_mode needed_mode, struct task_struct *t) { unsigned int mode;
@@ -78,7 +78,7 @@ static bool check_kcov_mode(enum kcov_mode needed_mode, struct task_struct *t) return mode == needed_mode; }
-static unsigned long canonicalize_ip(unsigned long ip) +static notrace unsigned long canonicalize_ip(unsigned long ip) { #ifdef CONFIG_RANDOMIZE_BASE ip -= kaslr_offset();