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| author | Paul Fulghum <paulkf@microgate.com> | 2022-11-15 18:38:32 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-11-22 17:52:57 +0100 |
| commit | 24ce048b0d4d4d8542c26459e53be4b7840d374c (patch) | |
| tree | 45e4155efc5af4251609b750aeb28cd887cd23e4 /drivers/tty | |
| parent | serial: stm32: move dma_request_chan() before clk_prepare_enable() (diff) | |
| download | linux-24ce048b0d4d4d8542c26459e53be4b7840d374c.tar.xz linux-24ce048b0d4d4d8542c26459e53be4b7840d374c.zip | |
tty: synclink_gt: unwind actions in error path of net device open
Resent again, last attempt still altered the plain text.
Zhengchao Shao <shaozhengchao@huawei.com> identified by inspection bugs in the error path of hdlcdev_open() in synclink_gt.c
The function did not fully unwind actions in the error path. The use of try_module_get()/module_put() is unnecessary, potentially hazardous and is removed. The synclink_gt driver is already pinned any point the net device is registered, a requirement for calling this entry point.
The call hdlc_open() to init the generic HDLC layer is moved to after driver level init/checks and proper rollback of previous actions is added. This is a more sensible ordering as the most common error paths are at the driver level and the driver level rollbacks require less processing than hdlc_open()/hdlc_close().
This has been tested with supported hardware.
Signed-off-by:Paul Fulghum <paulkf@microgate.com>
Link: https://lore.kernel.org/r/7599F007-8985-4469-BE00-52BD1530210E@microgate.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/synclink_gt.c | 19 |
1 files changed, 10 insertions, 9 deletions
diff --git a/drivers/tty/synclink_gt.c b/drivers/tty/synclink_gt.c index 25e9befdda3a..72b76cdde534 100644 --- a/drivers/tty/synclink_gt.c +++ b/drivers/tty/synclink_gt.c @@ -1433,16 +1433,8 @@ static int hdlcdev_open(struct net_device *dev) int rc; unsigned long flags; - if (!try_module_get(THIS_MODULE)) - return -EBUSY; - DBGINFO(("%s hdlcdev_open\n", dev->name)); - /* generic HDLC layer open processing */ - rc = hdlc_open(dev); - if (rc) - return rc; - /* arbitrate between network and tty opens */ spin_lock_irqsave(&info->netlock, flags); if (info->port.count != 0 || info->netcount != 0) { @@ -1461,6 +1453,16 @@ static int hdlcdev_open(struct net_device *dev) return rc; } + /* generic HDLC layer open processing */ + rc = hdlc_open(dev); + if (rc) { + shutdown(info); + spin_lock_irqsave(&info->netlock, flags); + info->netcount = 0; + spin_unlock_irqrestore(&info->netlock, flags); + return rc; + } + /* assert RTS and DTR, apply hardware settings */ info->signals |= SerialSignal_RTS | SerialSignal_DTR; program_hw(info); @@ -1506,7 +1508,6 @@ static int hdlcdev_close(struct net_device *dev) info->netcount=0; spin_unlock_irqrestore(&info->netlock, flags); - module_put(THIS_MODULE); return 0; } |