From: Trond Myklebust commit 5a67657a2e90c9e4a48518f95d4ba7777aa20fbb upstream. If rpc_queue_upcall() adds a new upcall to the rpci->pipe list just after rpc_pipe_release calls rpc_purge_list(), but before it calls gss_pipe_release (as rpci->ops->release_pipe(inode)), then the latter will free a message without deleting it from the rpci->pipe list. We will be left with a freed object on the rpc->pipe list. Most frequent symptoms are kernel crashes in rpc.gssd system calls on the pipe in question. Reported-by: J. Bruce Fields Signed-off-by: Trond Myklebust Signed-off-by: Greg Kroah-Hartman --- net/sunrpc/auth_gss/auth_gss.c | 9 +++++---- net/sunrpc/rpc_pipe.c | 6 +++--- 2 files changed, 8 insertions(+), 7 deletions(-) --- a/net/sunrpc/auth_gss/auth_gss.c +++ b/net/sunrpc/auth_gss/auth_gss.c @@ -717,17 +717,18 @@ gss_pipe_release(struct inode *inode) struct rpc_inode *rpci = RPC_I(inode); struct gss_upcall_msg *gss_msg; +restart: spin_lock(&inode->i_lock); - while (!list_empty(&rpci->in_downcall)) { + list_for_each_entry(gss_msg, &rpci->in_downcall, list) { - gss_msg = list_entry(rpci->in_downcall.next, - struct gss_upcall_msg, list); + if (!list_empty(&gss_msg->msg.list)) + continue; gss_msg->msg.errno = -EPIPE; atomic_inc(&gss_msg->count); __gss_unhash_msg(gss_msg); spin_unlock(&inode->i_lock); gss_release_msg(gss_msg); - spin_lock(&inode->i_lock); + goto restart; } spin_unlock(&inode->i_lock); --- a/net/sunrpc/rpc_pipe.c +++ b/net/sunrpc/rpc_pipe.c @@ -47,7 +47,7 @@ static void rpc_purge_list(struct rpc_in return; do { msg = list_entry(head->next, struct rpc_pipe_msg, list); - list_del(&msg->list); + list_del_init(&msg->list); msg->errno = err; destroy_msg(msg); } while (!list_empty(head)); @@ -207,7 +207,7 @@ rpc_pipe_release(struct inode *inode, st if (msg != NULL) { spin_lock(&inode->i_lock); msg->errno = -EAGAIN; - list_del(&msg->list); + list_del_init(&msg->list); spin_unlock(&inode->i_lock); rpci->ops->destroy_msg(msg); } @@ -267,7 +267,7 @@ rpc_pipe_read(struct file *filp, char __ if (res < 0 || msg->len == msg->copied) { filp->private_data = NULL; spin_lock(&inode->i_lock); - list_del(&msg->list); + list_del_init(&msg->list); spin_unlock(&inode->i_lock); rpci->ops->destroy_msg(msg); } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/