From: Chris Wilson chris@chris-wilson.co.uk
[ Upstream commit a7ef9b28aa8d72a1656fa6f0a01bbd1493886317 ]
Though the number of lock-acquisitions is tracked as unsigned long, this is passed as the divisor to div_s64() which interprets it as a s32, giving nonsense values with more than 2 billion acquisitons. E.g.
acquisitions holdtime-min holdtime-max holdtime-total holdtime-avg ------------------------------------------------------------------------- 2350439395 0.07 353.38 649647067.36 0.-32
Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Signed-off-by: Ingo Molnar mingo@kernel.org Cc: Peter Zijlstra peterz@infradead.org Link: https://lore.kernel.org/r/20200725185110.11588-1-chris@chris-wilson.co.uk Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/locking/lockdep_proc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c index 6fcc4650f0c48..53cc3bb7025a5 100644 --- a/kernel/locking/lockdep_proc.c +++ b/kernel/locking/lockdep_proc.c @@ -394,7 +394,7 @@ static void seq_lock_time(struct seq_file *m, struct lock_time *lt) seq_time(m, lt->min); seq_time(m, lt->max); seq_time(m, lt->total); - seq_time(m, lt->nr ? div_s64(lt->total, lt->nr) : 0); + seq_time(m, lt->nr ? div64_u64(lt->total, lt->nr) : 0); }
static void seq_stats(struct seq_file *m, struct lock_stat_data *data)