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authorPaul E. McKenney <paul.mckenney@linaro.org>2012-01-10 14:23:29 -0800
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2012-02-21 09:03:37 -0800
commit8146c4e2e2c1972216afece5c50e072e86120e42 (patch)
treedf8707527f59534595edb0be4f69255d4dff40c8
parent778d250a29224795e6320b58928bafa6b6104a06 (diff)
rcu: Check for callback invocation from offline CPUs
Because quiescent states are now reported from offline CPUs in CPU_DYING state, there is some possibility that such a CPU might note the end of a grace period and attempt to start invoking callbacks. This would be a very bad thing, and is supposed to be prevented by the fact that the CPU_DYING CPU gets rid of all its callbacks before reporting the quiescent state. However, there is other CPU-offline code in the kernel, and it is quite possible that someone will invoke RCU core processing from that code. Therefore, this commit adds a warning for this case. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
-rw-r--r--kernel/rcutree.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 575f91d03f0..ac3a810d2db 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -1373,6 +1373,7 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp)
* races with call_rcu() from interrupt handlers.
*/
local_irq_save(flags);
+ WARN_ON_ONCE(cpu_is_offline(smp_processor_id()));
bl = rdp->blimit;
trace_rcu_batch_start(rsp->name, rdp->qlen_lazy, rdp->qlen, bl);
list = rdp->nxtlist;