6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Trond Myklebust trond.myklebust@hammerspace.com
[ Upstream commit 5bbd6e863b15a85221e49b9bdb2d5d8f0bb91f3d ]
If rpc_signal_task() is called while a task is in an rpc_call_done() callback function, and the latter calls rpc_restart_call(), the task can end up looping due to the RPC_TASK_SIGNALLED flag being set without the tk_rpc_status being set. Removing the redundant mechanism for signalling the task fixes the looping behaviour.
Reported-by: Li Lingfeng lilingfeng3@huawei.com Fixes: 39494194f93b ("SUNRPC: Fix races with rpc_killall_tasks()") Signed-off-by: Trond Myklebust trond.myklebust@hammerspace.com Reviewed-by: Jeff Layton jlayton@kernel.org Signed-off-by: Anna Schumaker anna.schumaker@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/sunrpc/sched.h | 3 +-- include/trace/events/sunrpc.h | 3 +-- net/sunrpc/sched.c | 2 -- 3 files changed, 2 insertions(+), 6 deletions(-)
diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h index f80b90aca380a..a220b28904ca5 100644 --- a/include/linux/sunrpc/sched.h +++ b/include/linux/sunrpc/sched.h @@ -147,7 +147,6 @@ enum { RPC_TASK_NEED_XMIT, RPC_TASK_NEED_RECV, RPC_TASK_MSG_PIN_WAIT, - RPC_TASK_SIGNALLED, };
#define rpc_test_and_set_running(t) \ @@ -160,7 +159,7 @@ enum {
#define RPC_IS_ACTIVATED(t) test_bit(RPC_TASK_ACTIVE, &(t)->tk_runstate)
-#define RPC_SIGNALLED(t) test_bit(RPC_TASK_SIGNALLED, &(t)->tk_runstate) +#define RPC_SIGNALLED(t) (READ_ONCE(task->tk_rpc_status) == -ERESTARTSYS)
/* * Task priorities. diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h index ffe2679a13ced..b70f47a57bf6d 100644 --- a/include/trace/events/sunrpc.h +++ b/include/trace/events/sunrpc.h @@ -328,8 +328,7 @@ TRACE_EVENT(rpc_request, { (1UL << RPC_TASK_ACTIVE), "ACTIVE" }, \ { (1UL << RPC_TASK_NEED_XMIT), "NEED_XMIT" }, \ { (1UL << RPC_TASK_NEED_RECV), "NEED_RECV" }, \ - { (1UL << RPC_TASK_MSG_PIN_WAIT), "MSG_PIN_WAIT" }, \ - { (1UL << RPC_TASK_SIGNALLED), "SIGNALLED" }) + { (1UL << RPC_TASK_MSG_PIN_WAIT), "MSG_PIN_WAIT" })
DECLARE_EVENT_CLASS(rpc_task_running,
diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c index cef623ea15060..9b45fbdc90cab 100644 --- a/net/sunrpc/sched.c +++ b/net/sunrpc/sched.c @@ -864,8 +864,6 @@ void rpc_signal_task(struct rpc_task *task) if (!rpc_task_set_rpc_status(task, -ERESTARTSYS)) return; trace_rpc_task_signalled(task, task->tk_action); - set_bit(RPC_TASK_SIGNALLED, &task->tk_runstate); - smp_mb__after_atomic(); queue = READ_ONCE(task->tk_waitqueue); if (queue) rpc_wake_up_queued_task(queue, task);