linux-next/kernel/rcu
Paul E. McKenney 46faf9d8e1 rcu-tasks: Initialize data to eliminate RCU-tasks/do_exit() deadlocks
Holding a mutex across synchronize_rcu_tasks() and acquiring
that same mutex in code called from do_exit() after its call to
exit_tasks_rcu_start() but before its call to exit_tasks_rcu_stop()
results in deadlock.  This is by design, because tasks that are far
enough into do_exit() are no longer present on the tasks list, making
it a bit difficult for RCU Tasks to find them, let alone wait on them
to do a voluntary context switch.  However, such deadlocks are becoming
more frequent.  In addition, lockdep currently does not detect such
deadlocks and they can be difficult to reproduce.

In addition, if a task voluntarily context switches during that time
(for example, if it blocks acquiring a mutex), then this task is in an
RCU Tasks quiescent state.  And with some adjustments, RCU Tasks could
just as well take advantage of that fact.

This commit therefore initializes the data structures that will be needed
to rely on these quiescent states and to eliminate these deadlocks.

Link: https://lore.kernel.org/all/20240118021842.290665-1-chenzhongjin@huawei.com/

Reported-by: Chen Zhongjin <chenzhongjin@huawei.com>
Reported-by: Yang Jihong <yangjihong1@huawei.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Tested-by: Yang Jihong <yangjihong1@huawei.com>
Tested-by: Chen Zhongjin <chenzhongjin@huawei.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
2024-02-25 14:21:43 -08:00
..
Kconfig rcu: Employ jiffies-based backstop to callback time limit 2023-05-11 13:42:39 -07:00
Kconfig.debug rcu: Restrict access to RCU CPU stall notifiers 2023-12-12 02:31:22 +05:30
Makefile rcuperf: Change rcuperf to rcuscale 2020-08-24 18:39:24 -07:00
rcu_segcblist.c rcu: Use rcu_segcblist_segempty() instead of open coding it 2023-10-04 17:33:18 +02:00
rcu_segcblist.h rcu: Throttle callback invocation based on number of ready callbacks 2023-01-03 17:28:34 -08:00
rcu.h rcu-tasks: Initialize callback lists at rcu_init() time 2024-02-25 14:21:34 -08:00
rcuscale.c rcuscale: Move rcu_scale_writer() schedule_timeout_uninterruptible() to _idle() 2023-07-14 15:01:49 -07:00
rcutorture.c Merge branches 'doc.2023.12.13a', 'torture.2023.11.23a', 'fixes.2023.12.13a', 'rcu-tasks.2023.12.12b' and 'srcu.2023.12.13a' into rcu-merge.2023.12.13a 2023-12-14 01:21:31 +05:30
refscale.c refscale: Print out additional module parameters 2023-09-11 23:02:18 +02:00
srcutiny.c rcu: Dump memory object info if callback function is invalid 2023-09-13 22:29:12 +02:00
srcutree.c srcu: Explain why callbacks invocations can't run concurrently 2023-12-12 02:41:17 +05:30
sync.c rcu/sync: Use call_rcu_hurry() instead of call_rcu 2022-11-29 14:04:33 -08:00
tasks.h rcu-tasks: Initialize data to eliminate RCU-tasks/do_exit() deadlocks 2024-02-25 14:21:43 -08:00
tiny.c rcu-tasks: Initialize callback lists at rcu_init() time 2024-02-25 14:21:34 -08:00
tree_exp.h rcu: Defer RCU kthreads wakeup when CPU is dying 2024-01-24 22:46:17 +05:30
tree_nocb.h rcu: dynamically allocate the rcu-lazy shrinker 2023-10-04 10:32:24 -07:00
tree_plugin.h rcu: Mark additional concurrent load from ->cpu_no_qs.b.exp 2023-05-11 13:42:39 -07:00
tree_stall.h rcu: Restrict access to RCU CPU stall notifiers 2023-12-12 02:31:22 +05:30
tree.c rcu-tasks: Initialize callback lists at rcu_init() time 2024-02-25 14:21:34 -08:00
tree.h rcu/tree: Defer setting of jiffies during stall reset 2023-09-11 22:36:40 +02:00
update.c rcu: Restrict access to RCU CPU stall notifiers 2023-12-12 02:31:22 +05:30