On Fri, Mar 09, 2018 at 05:41:27AM +0800, kbuild test robot wrote: > tree: https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git > rcu/dev > head: b8909ec707bb5beba94e7c7d62cc6b3115ceae50 > commit: b8909ec707bb5beba94e7c7d62cc6b3115ceae50 [39/39] rcu: Protect all > sync_rcu_preempt_exp_done() with rcu_node lock > reproduce: > # apt-get install sparse > git checkout b8909ec707bb5beba94e7c7d62cc6b3115ceae50 > make ARCH=x86_64 allmodconfig > make C=1 CF=-D__CHECK_ENDIAN__ > > > sparse warnings: (new ones prefixed by >>) > [...] > kernel/rcu/tree.c:345:6: sparse: symbol 'rcu_dynticks_curr_cpu_in_eqs' was > not declared. Should it be static? > kernel/rcu/tree.c:3953:21: sparse: incorrect type in argument 1 (different > modifiers) @@ expected int ( *threadfn )( ... ) @@ got int ( [noreint ( > *threadfn )( ... ) @@ > kernel/rcu/tree.c:3953:21: expected int ( *threadfn )( ... ) > kernel/rcu/tree.c:3953:21: got int ( [noreturn] *<noident> )( ... ) > >> kernel/rcu/tree_exp.h:163:9: sparse: incorrect type in argument 1 > >> (different modifiers) @@ expected struct lockdep_map const *lock @@ > >> got strustruct lockdep_map const *lock @@ > kernel/rcu/tree_exp.h:163:9: expected struct lockdep_map const *lock > kernel/rcu/tree_exp.h:163:9: got struct lockdep_map [noderef] *<noident> > kernel/rcu/tree.c:1752:9: sparse: context imbalance in > 'rcu_start_future_gp' - different lock contexts for basic block > kernel/rcu/tree.c:2786:9: sparse: context imbalance in 'force_qs_rnp' - > different lock contexts for basic block > kernel/rcu/tree.c:2849:25: sparse: context imbalance in > 'force_quiescent_state' - unexpected unlock > kernel/rcu/tree_exp.h:203:9: sparse: too many warnings > > vim +163 kernel/rcu/tree_exp.h > > 151 > 152 /* > 153 * Return non-zero if there is no RCU expedited grace period in > progress > 154 * for the specified rcu_node structure, in other words, if all > CPUs and > 155 * tasks covered by the specified rcu_node structure have done > their bit > 156 * for the current expedited grace period. Works only for > preemptible > 157 * RCU -- other RCU implementation use other means. > 158 * > 159 * Caller must hold the specificed rcu_node structure's ->lock > 160 */ > 161 static bool sync_rcu_preempt_exp_done(struct rcu_node *rnp) > 162 { > > 163 lockdep_assert_held(&rnp->lock);
OK, so we need ACCESS_PRIVATE() to visit ->lock in rcu_node. I will
introduce something like:
#define rcu_node_lock_assert_held(rnp)
lockdep_assert_held(&ACCESS_PRIVATE(rnp, lock))
in v3.
Regards,
Boqun
> 164
> 165 return rnp->exp_tasks == NULL &&
> 166 READ_ONCE(rnp->expmask) == 0;
> 167 }
> 168
>
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