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authorPaul E. McKenney <paulmck@kernel.org>2022-10-14 13:39:43 +0200
committerAlexei Starovoitov <ast@kernel.org>2022-10-18 19:27:02 +0200
commite6c86c513f440bec5f1046539c7e3c6c653842da (patch)
treeb74b9661a63b5b201ae8d3f0072d05e2bcbd3798 /kernel/rcu/tasks.h
parentselftests/bpf: Use sys_pidfd_open() helper when possible (diff)
downloadlinux-e6c86c513f440bec5f1046539c7e3c6c653842da.tar.xz
linux-e6c86c513f440bec5f1046539c7e3c6c653842da.zip
rcu-tasks: Provide rcu_trace_implies_rcu_gp()
As an accident of implementation, an RCU Tasks Trace grace period also acts as an RCU grace period. However, this could change at any time. This commit therefore creates an rcu_trace_implies_rcu_gp() that currently returns true to codify this accident. Code relying on this accident must call this function to verify that this accident is still happening. Reported-by: Hou Tao <houtao@huaweicloud.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Martin KaFai Lau <martin.lau@linux.dev> Link: https://lore.kernel.org/r/20221014113946.965131-2-houtao@huaweicloud.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to '')
-rw-r--r--kernel/rcu/tasks.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index f5bf6fb430da..9435e5a7b53e 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -1535,6 +1535,8 @@ static void rcu_tasks_trace_postscan(struct list_head *hop)
{
// Wait for late-stage exiting tasks to finish exiting.
// These might have passed the call to exit_tasks_rcu_finish().
+
+ // If you remove the following line, update rcu_trace_implies_rcu_gp()!!!
synchronize_rcu();
// Any tasks that exit after this point will set
// TRC_NEED_QS_CHECKED in ->trc_reader_special.b.need_qs.