Hi Linus,
Please pull this fix into v7.1. The issue was introduced by a previous
fix PR rather than the v7.1 RCU merge window pull request, hence I'm
sending this "fix-on-fix" PR. The issue is because queuing a work on a
never-online CPU won't get the work callback executed, hence SRCU needs
to avoid doing that.
The following changes since commit 7fd2df204f342fc17d1a0bfcd474b24232fb0f32:
Linux 7.1-rc2 (2026-05-03 14:21:25 -0700)
are available in the Git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux.git
tags/rcu-fixes.v7.1-20260519a
for you to fetch changes up to 593889c401426004bd0ea0f6d4fcece728b03420:
srcu: Don't queue workqueue handlers to never-online CPUs (2026-05-18
12:27:18 -0700)
----------------------------------------------------------------
RCU fixes for v7.1
Fix a regression introduced by commit 61bbcfb50514 ("srcu: Push
srcu_node allocation to GP when non-preemptible"): SRCU may queue works
on CPUs that are "possible" but never have been online. In such a case,
the work callbacks may not be executed until the corresponding CPU gets
online, and as the callbacks accumulates, workqueue lockups will fire.
Fix this by avoiding queuing works on CPUs that have never been online.
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Regards,
Boqun
----------------------------------------------------------------
Paul E. McKenney (1):
srcu: Don't queue workqueue handlers to never-online CPUs
kernel/rcu/srcutree.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
