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cifs: fix GlobalMid_Lock bug in cifs_reconnect 

We can not hold the GlobalMid_Lock spinlock during the
dfs processing in cifs_reconnect since it invokes things that may sleep
and thus trigger :

BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:23

Thus we need to drop the spinlock during this code block.

RHBZ: 1716743

Cc: stable@vger.kernel.org
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Ronnie Sahlberg 2019-06-14 13:02:29 +10:00 committed by Steve French
parent 8d526d62db
commit 61cabc7b0a
1 changed files with 2 additions and 0 deletions
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2
fs/cifs/connect.c
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@ -476,6 +476,7 @@ cifs_reconnect(struct TCP_Server_Info *server)
spin_lock(&GlobalMid_Lock);
server->nr_targets = 1;
#ifdef CONFIG_CIFS_DFS_UPCALL
spin_unlock(&GlobalMid_Lock);
cifs_sb = find_super_by_tcp(server);
if (IS_ERR(cifs_sb)) {
rc = PTR_ERR(cifs_sb);
@ -493,6 +494,7 @@ cifs_reconnect(struct TCP_Server_Info *server)
}
cifs_dbg(FYI, "%s: will retry %d target(s)\n", __func__,
server->nr_targets);
spin_lock(&GlobalMid_Lock);
#endif
if (server->tcpStatus == CifsExiting) {
/* the demux thread will exit normally