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| author | Pavel Shilovsky <pshilov@microsoft.com> | 2016-11-29 11:31:23 -0800 |
|---|---|---|
| committer | Pavel Shilovsky <pshilov@microsoft.com> | 2016-12-05 12:52:01 -0800 |
| commit | 96a988ffeb90dba33a71c3826086fe67c897a183 (patch) | |
| tree | aeb1443b368e35a1af1bf5a51a55997eb5124371 /fs/cifs/smb2pdu.h | |
| parent | 53e0e11efe9289535b060a51d4cf37c25e0d0f2b (diff) | |
| download | linux-96a988ffeb90dba33a71c3826086fe67c897a183.tar.bz2 | |
CIFS: Fix a possible double locking of mutex during reconnect
With the current code it is possible to lock a mutex twice when
a subsequent reconnects are triggered. On the 1st reconnect we
reconnect sessions and tcons and then persistent file handles.
If the 2nd reconnect happens during the reconnecting of persistent
file handles then the following sequence of calls is observed:
cifs_reopen_file -> SMB2_open -> small_smb2_init -> smb2_reconnect
-> cifs_reopen_persistent_file_handles -> cifs_reopen_file (again!).
So, we are trying to acquire the same cfile->fh_mutex twice which
is wrong. Fix this by moving reconnecting of persistent handles to
the delayed work (smb2_reconnect_server) and submitting this work
every time we reconnect tcon in SMB2 commands handling codepath.
This can also lead to corruption of a temporary file list in
cifs_reopen_persistent_file_handles() because we can recursively
call this function twice.
Cc: Stable <stable@vger.kernel.org> # v4.9+
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Diffstat (limited to 'fs/cifs/smb2pdu.h')
| -rw-r--r-- | fs/cifs/smb2pdu.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h index fd3709e8de33..dc0d141f33e2 100644 --- a/fs/cifs/smb2pdu.h +++ b/fs/cifs/smb2pdu.h @@ -80,6 +80,8 @@ #define SMB2_SET_INFO cpu_to_le16(SMB2_SET_INFO_HE) #define SMB2_OPLOCK_BREAK cpu_to_le16(SMB2_OPLOCK_BREAK_HE) +#define SMB2_INTERNAL_CMD cpu_to_le16(0xFFFF) + #define NUMBER_OF_SMB2_COMMANDS 0x0013 /* BB FIXME - analyze following length BB */ |