From: Arnd Bergmann arnd@arndb.de
[ Upstream commit 622be33fcbc93e9b672b99ed338369eb5e843ac3 ]
The get_seconds() call is deprecated because it overflows on 32-bit architectures. The algorithm in rcu_torture_stall() can deal with the overflow, but another problem here is that using a CLOCK_REALTIME stamp can lead to a false-positive stall warning when a settimeofday() happens concurrently.
Using ktime_get_seconds() instead avoids those issues and will never overflow. The added cast to 'unsigned long' however is necessary to make ULONG_CMP_LT() work correctly.
Signed-off-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Paul E. McKenney paulmck@linux.vnet.ibm.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- kernel/rcu/rcutorture.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index 42fcb7f05fac..f42cf69ef539 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -1446,7 +1446,7 @@ static int rcu_torture_stall(void *args) VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff"); } if (!kthread_should_stop()) { - stop_at = get_seconds() + stall_cpu; + stop_at = ktime_get_seconds() + stall_cpu; /* RCU CPU stall is expected behavior in following code. */ rcu_read_lock(); if (stall_cpu_irqsoff) @@ -1455,7 +1455,8 @@ static int rcu_torture_stall(void *args) preempt_disable(); pr_alert("rcu_torture_stall start on CPU %d.\n", smp_processor_id()); - while (ULONG_CMP_LT(get_seconds(), stop_at)) + while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(), + stop_at)) continue; /* Induce RCU CPU stall warning. */ if (stall_cpu_irqsoff) local_irq_enable();