Messages in this thread Patch in this message | | | From | <> | Subject | [PATCH V3] time/sched_clock: mark sched_clock_read_begin/retry as notrace | Date | Tue, 29 Sep 2020 16:20:27 +0800 |
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From: Quanyang Wang <quanyang.wang@windriver.com>
Since sched_clock_read_begin and sched_clock_read_retry are called by notrace function sched_clock, they shouldn't be traceable either, or else ftrace_graph_caller will run into a dead loop on the path as below (arm for instance):
ftrace_graph_caller prepare_ftrace_return function_graph_enter ftrace_push_return_trace trace_clock_local sched_clock sched_clock_read_begin/retry
Fixes: 1b86abc1c645 ("sched_clock: Expose struct clock_read_data") Signed-off-by: Quanyang Wang <quanyang.wang@windriver.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- Changes: V2: Add notrace to sched_clock_read_retry according to Peter's suggestion. V3: Adjust the placement of notrace according to Peter's suggestion.
kernel/time/sched_clock.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c index 1c03eec6ca9b..f629e3f5afbe 100644 --- a/kernel/time/sched_clock.c +++ b/kernel/time/sched_clock.c @@ -68,13 +68,13 @@ static inline u64 notrace cyc_to_ns(u64 cyc, u32 mult, u32 shift) return (cyc * mult) >> shift; } -struct clock_read_data *sched_clock_read_begin(unsigned int *seq) +notrace struct clock_read_data *sched_clock_read_begin(unsigned int *seq) { *seq = raw_read_seqcount_latch(&cd.seq); return cd.read_data + (*seq & 1); } -int sched_clock_read_retry(unsigned int seq) +notrace int sched_clock_read_retry(unsigned int seq) { return read_seqcount_retry(&cd.seq, seq); } -- 2.17.1
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