BMC/Intel-BMC/linux.git/net/sunrpc/clnt.c, branch dev-5.8

SUNRPC: Set SOFTCONN when destroying GSS contexts

2020-06-11T17:33:48+00:00

Move the RPC_TASK_SOFTCONN flag into rpc_call_null_helper(). The only minor behavior change is that it is now also set when destroying GSS contexts. This gives a better guarantee that gss_send_destroy_context() will not hang for long if a connection cannot be established. Signed-off-by: Chuck Lever Signed-off-by: Anna Schumaker

SUNRPC: rpc_call_null_helper() should set RPC_TASK_SOFT

2020-06-11T17:33:48+00:00

Clean up. All of rpc_call_null_helper() call sites assert RPC_TASK_SOFT, so move that setting into rpc_call_null_helper() itself. Signed-off-by: Chuck Lever Signed-off-by: Anna Schumaker

SUNRPC: rpc_call_null_helper() already sets RPC_TASK_NULLCREDS

2020-06-11T17:33:48+00:00

Clean up. Commit a52458b48af1 ("NFS/NFSD/SUNRPC: replace generic creds with 'struct cred'.") made rpc_call_null_helper() set RPC_TASK_NULLCREDS unconditionally. Therefore there's no need for rpc_call_null_helper()'s call sites to set RPC_TASK_NULLCREDS. Signed-off-by: Chuck Lever Signed-off-by: Anna Schumaker

SUNRPC: trace RPC client lifetime events

2020-06-11T17:33:48+00:00

The "create" tracepoint records parts of the rpc_create arguments, and the shutdown tracepoint records when the rpc_clnt is about to signal pending tasks and destroy auths. Signed-off-by: Chuck Lever Signed-off-by: Anna Schumaker

SUNRPC: Split the xdr_buf event class

2020-06-11T17:33:48+00:00

To help tie the recorded xdr_buf to a particular RPC transaction, the client side version of this class should display task ID information and the server side one should show the request's XID. Signed-off-by: Chuck Lever Signed-off-by: Anna Schumaker

SUNRPC: Add tracepoint to rpc_call_rpcerror()

2020-06-11T17:33:48+00:00

Add a tracepoint in another common exit point for failing RPCs. Signed-off-by: Chuck Lever Signed-off-by: Anna Schumaker

SUNRPC: 'Directory with parent 'rpc_clnt' already present!'

2020-05-14T20:31:09+00:00

Each rpc_client has a cl_clid which is allocated from a global ida, and a debugfs directory which is named after cl_clid. We're releasing the cl_clid before we free the debugfs directory named after it. As soon as the cl_clid is released, that value is available for another newly created client. That leaves a window where another client may attempt to create a new debugfs directory with the same name as the not-yet-deleted debugfs directory from the dying client. Symptoms are log messages like Directory 4 with parent 'rpc_clnt' already present! Fixes: 7c4310ff5642 "SUNRPC: defer slow parts of rpc_free_client() to a workqueue." Signed-off-by: J. Bruce Fields Signed-off-by: Trond Myklebust

SUNRPC: Signalled ASYNC tasks need to exit

2020-05-11T18:06:50+00:00

Ensure that signalled ASYNC rpc_tasks exit immediately instead of spinning until a timeout (or forever). To avoid checking for the signal flag on every scheduler iteration, the check is instead introduced in the client's finite state machine. Signed-off-by: Chuck Lever Fixes: ae67bd3821bb ("SUNRPC: Fix up task signalling") Signed-off-by: Trond Myklebust

SUNRPC: fix use-after-free in rpc_free_client_work()

2020-05-10T23:44:56+00:00

Parts of rpc_free_client() were recently moved to a separate rpc_free_clent_work(). This introduced a use-after-free as rpc_clnt_remove_pipedir() calls rpc_net_ns(), and that uses clnt->cl_xprt which has already been freed. So move the call to xprt_put() after the call to rpc_clnt_remove_pipedir(). Reported-by: syzbot+22b5ef302c7c40d94ea8@syzkaller.appspotmail.com Fixes: 7c4310ff5642 ("SUNRPC: defer slow parts of rpc_free_client() to a workqueue.") Signed-off-by: NeilBrown Signed-off-by: Trond Myklebust

SUNRPC: defer slow parts of rpc_free_client() to a workqueue.

2020-04-28T19:58:38+00:00

The rpciod workqueue is on the write-out path for freeing dirty memory, so it is important that it never block waiting for memory to be allocated - this can lead to a deadlock. rpc_execute() - which is often called by an rpciod work item - calls rcp_task_release_client() which can lead to rpc_free_client(). rpc_free_client() makes two calls which could potentially block wating for memory allocation. rpc_clnt_debugfs_unregister() calls into debugfs and will block while any of the debugfs files are being accessed. In particular it can block while any of the 'open' methods are being called and all of these use malloc for one thing or another. So this can deadlock if the memory allocation waits for NFS to complete some writes via rpciod. rpc_clnt_remove_pipedir() can take the inode_lock() and while it isn't obvious that memory allocations can happen while the lock it held, it is safer to assume they might and to not let rpciod call rpc_clnt_remove_pipedir(). So this patch moves these two calls (together with the final kfree() and rpciod_down()) into a work-item to be run from the system work-queue. rpciod can continue its important work, and the final stages of the free can happen whenever they happen. I have seen this deadlock on a 4.12 based kernel where debugfs used synchronize_srcu() when removing objects. synchronize_srcu() requires a workqueue and there were no free workther threads and none could be allocated. While debugsfs no longer uses SRCU, I believe the deadlock is still possible. Signed-off-by: NeilBrown Signed-off-by: Trond Myklebust