From 2f02f7aea7b6c9a9312846c006e076ae6ad026a4 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 7 Apr 2016 17:23:03 +0100 Subject: [PATCH] afs: Wait for outstanding async calls before closing rxrpc socket The afs filesystem needs to wait for any outstanding asynchronous calls (such as FS.GiveUpCallBacks cleaning up the callbacks lodged with a server) to complete before closing the AF_RXRPC socket when unloading the module. This may occur if the module is removed too quickly after unmounting all filesystems. This will produce an error report that looks like: AFS: Assertion failed 1 == 0 is false 0x1 == 0x0 is false ------------[ cut here ]------------ kernel BUG at ../fs/afs/rxrpc.c:135! ... RIP: 0010:[] afs_close_socket+0xec/0x107 [kafs] ... Call Trace: [] afs_exit+0x1f/0x57 [kafs] [] SyS_delete_module+0xec/0x17d [] entry_SYSCALL_64_fastpath+0x12/0x6b Signed-off-by: David Howells Signed-off-by: David S. Miller --- fs/afs/rxrpc.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/fs/afs/rxrpc.c b/fs/afs/rxrpc.c index b50642870a43..b4d337ad6e36 100644 --- a/fs/afs/rxrpc.c +++ b/fs/afs/rxrpc.c @@ -65,6 +65,12 @@ static void afs_async_workfn(struct work_struct *work) call->async_workfn(call); } +static int afs_wait_atomic_t(atomic_t *p) +{ + schedule(); + return 0; +} + /* * open an RxRPC socket and bind it to be a server for callback notifications * - the socket is left in blocking mode and non-blocking ops use MSG_DONTWAIT @@ -126,13 +132,16 @@ void afs_close_socket(void) { _enter(""); + wait_on_atomic_t(&afs_outstanding_calls, afs_wait_atomic_t, + TASK_UNINTERRUPTIBLE); + _debug("no outstanding calls"); + sock_release(afs_socket); _debug("dework"); destroy_workqueue(afs_async_calls); ASSERTCMP(atomic_read(&afs_outstanding_skbs), ==, 0); - ASSERTCMP(atomic_read(&afs_outstanding_calls), ==, 0); _leave(""); } @@ -178,8 +187,6 @@ static void afs_free_call(struct afs_call *call) { _debug("DONE %p{%s} [%d]", call, call->type->name, atomic_read(&afs_outstanding_calls)); - if (atomic_dec_return(&afs_outstanding_calls) == -1) - BUG(); ASSERTCMP(call->rxcall, ==, NULL); ASSERT(!work_pending(&call->async_work)); @@ -188,6 +195,9 @@ static void afs_free_call(struct afs_call *call) kfree(call->request); kfree(call); + + if (atomic_dec_and_test(&afs_outstanding_calls)) + wake_up_atomic_t(&afs_outstanding_calls); } /* -- 2.20.1