kernel_optimize_test/kernel/sched
Frederic Weisbecker e713bdd791 rcu/nocb: Perform deferred wake up before last idle's need_resched() check
commit 43789ef3f7d61aa7bed0cb2764e588fc990c30ef upstream.

Entering RCU idle mode may cause a deferred wake up of an RCU NOCB_GP
kthread (rcuog) to be serviced.

Usually a local wake up happening while running the idle task is handled
in one of the need_resched() checks carefully placed within the idle
loop that can break to the scheduler.

Unfortunately the call to rcu_idle_enter() is already beyond the last
generic need_resched() check and we may halt the CPU with a resched
request unhandled, leaving the task hanging.

Fix this with splitting the rcuog wakeup handling from rcu_idle_enter()
and place it before the last generic need_resched() check in the idle
loop. It is then assumed that no call to call_rcu() will be performed
after that in the idle loop until the CPU is put in low power mode.

Fixes: 96d3fd0d31 (rcu: Break call_rcu() deadlock involving scheduler and perf)
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20210131230548.32970-3-frederic@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-04 11:38:35 +01:00
..
autogroup.c
autogroup.h
clock.c
completion.c
core.c sched: Reenable interrupts in do_sched_yield() 2020-12-30 11:52:59 +01:00
cpuacct.c
cpudeadline.c
cpudeadline.h
cpufreq_schedutil.c cpufreq: Introduce governor flags 2020-11-10 18:31:17 +01:00
cpufreq.c
cpupri.c
cpupri.h
cputime.c
deadline.c sched/deadline: Fix sched_dl_global_validate() 2020-12-30 11:52:59 +01:00
debug.c sched/debug: Fix memory corruption caused by multiple small reads of flags 2020-11-10 18:38:49 +01:00
fair.c sched/eas: Don't update misfit status if the task is pinned 2021-03-04 11:37:44 +01:00
features.h sched/rt: Disable RT_RUNTIME_SHARE by default 2020-09-25 14:23:24 +02:00
idle.c rcu/nocb: Perform deferred wake up before last idle's need_resched() check 2021-03-04 11:38:35 +01:00
isolation.c
loadavg.c
Makefile
membarrier.c membarrier: Execute SYNC_CORE on the calling thread 2020-12-09 09:37:43 +01:00
pelt.c
pelt.h
psi.c
rt.c treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
sched-pelt.h
sched.h sched/deadline: Fix sched_dl_global_validate() 2020-12-30 11:52:59 +01:00
smp.h
stats.c
stats.h
stop_task.c treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
swait.c
topology.c Scheduler changes for v5.10: 2020-10-12 12:56:01 -07:00
wait_bit.c
wait.c