From 8428817dc40006dca0a531cfa06e89cb3b41790d Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Sat, 5 Jan 2019 15:25:29 +0300 Subject: cifs: Fix a debug message This debug message was never shown because it was checking for NULL returns but extract_hostname() returns error pointers. Fixes: 93d5cb517db3 ("cifs: Add support for failover in cifs_reconnect()") Signed-off-by: Dan Carpenter Signed-off-by: Steve French Reviewed-by: Paulo Alcantara --- fs/cifs/connect.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'fs/cifs/connect.c') diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index f66529679ca2..683310f26171 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -433,9 +433,10 @@ static void reconn_inval_dfs_target(struct TCP_Server_Info *server, kfree(server->hostname); server->hostname = extract_hostname(name); - if (!server->hostname) { - cifs_dbg(FYI, "%s: failed to extract hostname from target: %d\n", - __func__, -ENOMEM); + if (IS_ERR(server->hostname)) { + cifs_dbg(FYI, + "%s: failed to extract hostname from target: %ld\n", + __func__, PTR_ERR(server->hostname)); } } -- cgit v1.2.2 From ef68e831840c40c7d01b328b3c0f5d8c4796c232 Mon Sep 17 00:00:00 2001 From: Pavel Shilovsky Date: Fri, 18 Jan 2019 17:25:36 -0800 Subject: CIFS: Do not reconnect TCP session in add_credits() When executing add_credits() we currently call cifs_reconnect() if the number of credits is zero and there are no requests in flight. In this case we may call cifs_reconnect() recursively twice and cause memory corruption given the following sequence of functions: mid1.callback() -> add_credits() -> cifs_reconnect() -> -> mid2.callback() -> add_credits() -> cifs_reconnect(). Fix this by avoiding to call cifs_reconnect() in add_credits() and checking for zero credits in the demultiplex thread. Cc: Signed-off-by: Pavel Shilovsky Reviewed-by: Ronnie Sahlberg Signed-off-by: Steve French --- fs/cifs/connect.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'fs/cifs/connect.c') diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index 683310f26171..8463c940e0e5 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -720,6 +720,21 @@ server_unresponsive(struct TCP_Server_Info *server) return false; } +static inline bool +zero_credits(struct TCP_Server_Info *server) +{ + int val; + + spin_lock(&server->req_lock); + val = server->credits + server->echo_credits + server->oplock_credits; + if (server->in_flight == 0 && val == 0) { + spin_unlock(&server->req_lock); + return true; + } + spin_unlock(&server->req_lock); + return false; +} + static int cifs_readv_from_socket(struct TCP_Server_Info *server, struct msghdr *smb_msg) { @@ -732,6 +747,12 @@ cifs_readv_from_socket(struct TCP_Server_Info *server, struct msghdr *smb_msg) for (total_read = 0; msg_data_left(smb_msg); total_read += length) { try_to_freeze(); + /* reconnect if no credits and no requests in flight */ + if (zero_credits(server)) { + cifs_reconnect(server); + return -ECONNABORTED; + } + if (server_unresponsive(server)) return -ECONNABORTED; if (cifs_rdma_enabled(server) && server->smbd_conn) -- cgit v1.2.2