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Description of problem:
The problem is that for the case of priority queues, we
have to assume that __rpc_remove_wait_queue_priority will move new
elements from the tk_wait.links lists into the queue->tasks[] list.
We therefore cannot use list_for_each_entry_safe() on queue->tasks[],
since that will skip these new tasks that __rpc_remove_wait_queue_priority
is adding.
Without this fix, rpc_wake_up and rpc_wake_up_status will both fail
to wake up all functions on priority wait queues, which can result
in some nasty hangs.
Version-Release number of selected component (if applicable):
How reproducible:
Sometimes
Additional info:
Upstream commit:
commit 540a0f7584169651f485e8ab67461fcb06934e38
Author: Trond Myklebust <Trond.Myklebust>
Date: Mon Mar 19 13:39:35 2012 -0400
SUNRPC: We must not use list_for_each_entry_safe() in rpc_wake_up()
Comment 1RHEL Program Management
2012-04-03 14:20:07 UTC
This request was evaluated by Red Hat Product Management for inclusion
in a Red Hat Enterprise Linux maintenance release. Product Management has
requested further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products. This request is not yet committed for inclusion in an Update release.
Description of problem: The problem is that for the case of priority queues, we have to assume that __rpc_remove_wait_queue_priority will move new elements from the tk_wait.links lists into the queue->tasks[] list. We therefore cannot use list_for_each_entry_safe() on queue->tasks[], since that will skip these new tasks that __rpc_remove_wait_queue_priority is adding. Without this fix, rpc_wake_up and rpc_wake_up_status will both fail to wake up all functions on priority wait queues, which can result in some nasty hangs. Version-Release number of selected component (if applicable): How reproducible: Sometimes Additional info: Upstream commit: commit 540a0f7584169651f485e8ab67461fcb06934e38 Author: Trond Myklebust <Trond.Myklebust> Date: Mon Mar 19 13:39:35 2012 -0400 SUNRPC: We must not use list_for_each_entry_safe() in rpc_wake_up()