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    Subject[PATCH 5.10 203/593] cifs: fix missing spinlock around update to ses->status
    Date
    From: Steve French <stfrench@microsoft.com>

    [ Upstream commit 0060a4f28a9ef45ae8163c0805e944a2b1546762 ]

    In the other places where we update ses->status we protect the
    updates via GlobalMid_Lock. So to be consistent add the same
    locking around it in cifs_put_smb_ses where it was missing.

    Addresses-Coverity: 1268904 ("Data race condition")
    Signed-off-by: Steve French <stfrench@microsoft.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    fs/cifs/cifsglob.h | 3 ++-
    fs/cifs/connect.c | 5 ++++-
    2 files changed, 6 insertions(+), 2 deletions(-)

    diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
    index 248ee81e0151..6599069be690 100644
    --- a/fs/cifs/cifsglob.h
    +++ b/fs/cifs/cifsglob.h
    @@ -979,7 +979,7 @@ struct cifs_ses {
    struct mutex session_mutex;
    struct TCP_Server_Info *server; /* pointer to server info */
    int ses_count; /* reference counter */
    - enum statusEnum status;
    + enum statusEnum status; /* updates protected by GlobalMid_Lock */
    unsigned overrideSecFlg; /* if non-zero override global sec flags */
    char *serverOS; /* name of operating system underlying server */
    char *serverNOS; /* name of network operating system of server */
    @@ -1863,6 +1863,7 @@ require use of the stronger protocol */
    * list operations on pending_mid_q and oplockQ
    * updates to XID counters, multiplex id and SMB sequence numbers
    * list operations on global DnotifyReqList
    + * updates to ses->status
    * tcp_ses_lock protects:
    * list operations on tcp and SMB session lists
    * tcon->open_file_lock protects the list of open files hanging off the tcon
    diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
    index aabaebd1535f..fb7088d57e46 100644
    --- a/fs/cifs/connect.c
    +++ b/fs/cifs/connect.c
    @@ -2829,9 +2829,12 @@ void cifs_put_smb_ses(struct cifs_ses *ses)
    spin_unlock(&cifs_tcp_ses_lock);
    return;
    }
    + spin_unlock(&cifs_tcp_ses_lock);
    +
    + spin_lock(&GlobalMid_Lock);
    if (ses->status == CifsGood)
    ses->status = CifsExiting;
    - spin_unlock(&cifs_tcp_ses_lock);
    + spin_unlock(&GlobalMid_Lock);

    cifs_free_ipc(ses);

    --
    2.30.2


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