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| author | Paul E. McKenney <paulmck@kernel.org> | 2023-10-03 10:30:01 -0700 |
|---|---|---|
| committer | Neeraj Upadhyay (AMD) <neeraj.iitr10@gmail.com> | 2023-12-14 01:15:52 +0530 |
| commit | 1b7178b23dc915fc6801ff3eeb6c4ffa51b562f7 (patch) | |
| tree | f3f36ce6646d0e70ea9e9fd1dfdff54758c994b7 /Documentation | |
| parent | 493dffa3ab07b5d2c0b7bd5de5bff6e85f01f52a (diff) | |
| download | linux-stable-1b7178b23dc915fc6801ff3eeb6c4ffa51b562f7.tar.gz linux-stable-1b7178b23dc915fc6801ff3eeb6c4ffa51b562f7.tar.bz2 linux-stable-1b7178b23dc915fc6801ff3eeb6c4ffa51b562f7.zip | |
doc: Clarify RCU Tasks reader/updater checklist
Currently, the reader/updater compatibility rules for the three RCU
Tasks flavors are squished together in a single paragraph, which can
result in confusion. This commit therefore splits them out into a list,
clearly showing the distinction between these flavors.
Link: https://lore.kernel.org/all/20231002211936.5948253e@gandalf.local.home/
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.iitr10@gmail.com>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/RCU/checklist.rst | 25 |
1 files changed, 16 insertions, 9 deletions
diff --git a/Documentation/RCU/checklist.rst b/Documentation/RCU/checklist.rst index bd3c58c44bef..2d42998a89a6 100644 --- a/Documentation/RCU/checklist.rst +++ b/Documentation/RCU/checklist.rst @@ -241,15 +241,22 @@ over a rather long period of time, but improvements are always welcome! srcu_struct. The rules for the expedited RCU grace-period-wait primitives are the same as for their non-expedited counterparts. - If the updater uses call_rcu_tasks() or synchronize_rcu_tasks(), - then the readers must refrain from executing voluntary - context switches, that is, from blocking. If the updater uses - call_rcu_tasks_trace() or synchronize_rcu_tasks_trace(), then - the corresponding readers must use rcu_read_lock_trace() and - rcu_read_unlock_trace(). If an updater uses call_rcu_tasks_rude() - or synchronize_rcu_tasks_rude(), then the corresponding readers - must use anything that disables preemption, for example, - preempt_disable() and preempt_enable(). + Similarly, it is necessary to correctly use the RCU Tasks flavors: + + a. If the updater uses synchronize_rcu_tasks() or + call_rcu_tasks(), then the readers must refrain from + executing voluntary context switches, that is, from + blocking. + + b. If the updater uses call_rcu_tasks_trace() + or synchronize_rcu_tasks_trace(), then the + corresponding readers must use rcu_read_lock_trace() + and rcu_read_unlock_trace(). + + c. If an updater uses call_rcu_tasks_rude() or + synchronize_rcu_tasks_rude(), then the corresponding + readers must use anything that disables preemption, + for example, preempt_disable() and preempt_enable(). Mixing things up will result in confusion and broken kernels, and has even resulted in an exploitable security issue. Therefore, |