2.6.39-stable review patch. If anyone has any objections, please let us know.
------------------ From: Shaohua Li <[email protected]> commit 3181faa85bda3dc3f5e630a1846526c9caaa38e3 upstream. I got a rcu warnning at boot. the ioc->ioc_data is rcu_deferenced, but doesn't hold rcu_read_lock. Signed-off-by: Shaohua Li <[email protected]> Signed-off-by: Jens Axboe <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- block/cfq-iosched.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -2704,11 +2704,14 @@ static void __cfq_exit_single_io_context smp_wmb(); cic->key = cfqd_dead_key(cfqd); + rcu_read_lock(); if (rcu_dereference(ioc->ioc_data) == cic) { + rcu_read_unlock(); spin_lock(&ioc->lock); rcu_assign_pointer(ioc->ioc_data, NULL); spin_unlock(&ioc->lock); - } + } else + rcu_read_unlock(); if (cic->cfqq[BLK_RW_ASYNC]) { cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]); _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
