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mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-17 01:34:00 +08:00
linux-next/kernel/rcu
Frederic Weisbecker f8bb5cae96 rcu/nocb: Trigger self-IPI on late deferred wake up before user resume
Entering RCU idle mode may cause a deferred wake up of an RCU NOCB_GP
kthread (rcuog) to be serviced.

Unfortunately the call to rcu_user_enter() is already past the last
rescheduling opportunity before we resume to userspace or to guest mode.
We may escape there with the woken task ignored.

The ultimate resort to fix every callsites is to trigger a self-IPI
(nohz_full depends on arch to implement arch_irq_work_raise()) that will
trigger a reschedule on IRQ tail or guest exit.

Eventually every site that want a saner treatment will need to carefully
place a call to rcu_nocb_flush_deferred_wakeup() before the last explicit
need_resched() check upon resume.

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/20210131230548.32970-4-frederic@kernel.org
2021-02-17 14:12:43 +01:00
..
Kconfig rcu: Clarify nocb kthreads naming in RCU_NOCB_CPU config 2020-11-19 19:37:16 -08:00
Kconfig.debug Merge branch 'strictgp.2020.08.24a' into HEAD 2020-09-03 09:47:42 -07:00
Makefile rcuperf: Change rcuperf to rcuscale 2020-08-24 18:39:24 -07:00
rcu_segcblist.c rcu/segcblist: Prevent useless GP start if no CBs to accelerate 2020-09-03 09:39:59 -07:00
rcu_segcblist.h rcu: Implement rcu_segcblist_is_offloaded() config dependent 2020-11-19 19:37:16 -08:00
rcu.h rcutorture: Make grace-period kthread report match RCU flavor being tested 2020-11-02 17:12:43 -08:00
rcuscale.c rcuscale: Prevent hangs for invalid arguments 2020-11-06 17:13:51 -08:00
rcutorture.c Merge branches 'cpuinfo.2020.11.06a', 'doc.2020.11.06a', 'fixes.2020.11.19b', 'lockdep.2020.11.02a', 'tasks.2020.11.06a' and 'torture.2020.11.06a' into HEAD 2020-11-19 19:37:47 -08:00
refscale.c refscale: Prevent hangs for invalid arguments 2020-11-06 17:13:51 -08:00
srcutiny.c rcu: Use CONFIG_PREEMPTION where appropriate 2019-12-09 12:37:51 -08:00
srcutree.c Merge branches 'cpuinfo.2020.11.06a', 'doc.2020.11.06a', 'fixes.2020.11.19b', 'lockdep.2020.11.02a', 'tasks.2020.11.06a' and 'torture.2020.11.06a' into HEAD 2020-11-19 19:37:47 -08:00
sync.c rcu/sync: Simplify the state machine 2019-05-28 09:05:23 -07:00
tasks.h Merge branch 'rcu/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu 2021-01-04 10:55:19 -08:00
tiny.c rcu: Rename *_kfree_callback/*_kfree_rcu_offset/kfree_call_* 2020-06-29 11:59:25 -07:00
tree_exp.h rcu: Initialize at declaration time in rcu_exp_handler() 2020-08-24 18:36:03 -07:00
tree_plugin.h rcu/nocb: Trigger self-IPI on late deferred wake up before user resume 2021-02-17 14:12:43 +01:00
tree_stall.h rcu: Panic after fixed number of stalls 2020-11-19 19:37:16 -08:00
tree.c rcu/nocb: Trigger self-IPI on late deferred wake up before user resume 2021-02-17 14:12:43 +01:00
tree.h rcu/nocb: Trigger self-IPI on late deferred wake up before user resume 2021-02-17 14:12:43 +01:00
update.c Merge tag 'core-rcu-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2020-10-18 14:34:50 -07:00