| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.1 014/121] cifs: fix GlobalMid_Lock bug in cifs_reconnect | Date | Mon, 24 Jun 2019 17:55:46 +0800 |
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From: Ronnie Sahlberg <lsahlber@redhat.com>
commit 61cabc7b0a5cf0d3c532cfa96594c801743fe7f6 upstream.
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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/cifs/connect.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -478,6 +478,7 @@ cifs_reconnect(struct TCP_Server_Info *s 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); @@ -495,6 +496,7 @@ cifs_reconnect(struct TCP_Server_Info *s } 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
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