linux-kernel - Should RCU_BOOST kernels use hrtimers in GP kthread?

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 16 Feb 2021 10:36:09 -0800
From:   "Paul E. McKenney" <paulmck@...nel.org>
To:     bigeasy@...utronix.de
Cc:     linux-kernel@...r.kernel.org, rcu@...r.kernel.org
Subject: Should RCU_BOOST kernels use hrtimers in GP kthread?

Hello, Sebastian,

I punted on this for the moment by making RCU priority boosting testing
depend on CONFIG_PREEMPT_RT, but longer term I am wondering if RCU's
various timed delays and timeouts should use hrtimers rather than normal
timers in kernels built with CONFIG_RCU_BOOST.  As it is, RCU priority
boosting can be defeated if any of the RCU grace-period kthread's timeouts
are serviced by the non-realtime ksoftirqd.

This might require things like swait_event_idle_hrtimeout_exclusive(),
either as primitives or just open coded.

Thoughts?

							Thanx, Paul