[PATCH] deal with rmmod/put_io_context() races

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 2 insertions, 0 deletions

diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index caa8fcf5474b..6dc769182052 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -3477,10 +3477,12 @@ void put_io_context(struct io_context *ioc)
         BUG_ON(atomic_read(&ioc->refcount) == 0);
 
         if (atomic_dec_and_test(&ioc->refcount)) {
+                rcu_read_lock();
                 if (ioc->aic && ioc->aic->dtor)
                         ioc->aic->dtor(ioc->aic);
                 if (ioc->cic && ioc->cic->dtor)
                         ioc->cic->dtor(ioc->cic);
+                rcu_read_unlock();
 
                 kmem_cache_free(iocontext_cachep, ioc);
         }