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6343402ac3
Once either rcutree_online_cpu() or rcutree_dead_cpu() is invoked concurrently, the following rcu_boost_kthread_setaffinity() race can occur: CPU 1 CPU2 mask = rcu_rnp_online_cpus(rnp); ... mask = rcu_rnp_online_cpus(rnp); ... set_cpus_allowed_ptr(t, cm); set_cpus_allowed_ptr(t, cm); This results in CPU2's update being overwritten by that of CPU1, and thus the possibility of ->boost_kthread_task continuing to run on a to-be-offlined CPU. This commit therefore eliminates this race by relying on the pre-existing acquisition of ->boost_kthread_mutex to serialize the full process of changing the affinity of ->boost_kthread_task. Signed-off-by: Pingfan Liu <kernelfans@gmail.com> Cc: David Woodhouse <dwmw@amazon.co.uk> Cc: Frederic Weisbecker <frederic@kernel.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: "Jason A. Donenfeld" <Jason@zx2c4.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> |
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.. | ||
Kconfig | ||
Kconfig.debug | ||
Makefile | ||
rcu.h | ||
rcu_segcblist.c | ||
rcu_segcblist.h | ||
rcuscale.c | ||
rcutorture.c | ||
refscale.c | ||
srcutiny.c | ||
srcutree.c | ||
sync.c | ||
tasks.h | ||
tiny.c | ||
tree.c | ||
tree.h | ||
tree_exp.h | ||
tree_nocb.h | ||
tree_plugin.h | ||
tree_stall.h | ||
update.c |