mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-08-28 11:49:32 +00:00
Code Issues Releases Wiki Activity

rcu: Mark rcu_state.ncpus to detect concurrent writes

Browse source 
The rcu_state structure's ncpus field is only to be modified by the
CPU-hotplug CPU-online code path, which is single-threaded.  This
commit therefore enlists KCSAN's help in enforcing this restriction.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Paul E. McKenney 2020-02-10 05:29:58 -08:00
parent 4f58820fd7
commit 2f08469563
1 changed files with 1 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

1
kernel/rcu/tree.c
View file

@ -3612,6 +3612,7 @@ void rcu_cpu_starting(unsigned int cpu)
nbits = bitmap_weight(&oldmask, BITS_PER_LONG);
/* Allow lockless access for expedited grace periods. */
smp_store_release(&rcu_state.ncpus, rcu_state.ncpus + nbits); /* ^^^ */
ASSERT_EXCLUSIVE_WRITER(rcu_state.ncpus);
rcu_gpnum_ovf(rnp, rdp); /* Offline-induced counter wrap? */
rdp->rcu_onl_gp_seq = READ_ONCE(rcu_state.gp_seq);
rdp->rcu_onl_gp_flags = READ_ONCE(rcu_state.gp_flags);