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| author | Johan Hovold <jhovold@gmail.com> | 2013-07-26 11:55:17 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-08-11 18:35:21 -0700 |
| commit | d614a64a0193ecc3c8d19774e9143173ad11af12 (patch) | |
| tree | 2aebeeafa31317bd811e15ce5b8b59ee3bac8fad | |
| parent | 9b0f8f01765acdf7c84078b63d2e34c2b2dcafa8 (diff) | |
| download | linux-3.10-d614a64a0193ecc3c8d19774e9143173ad11af12.tar.gz linux-3.10-d614a64a0193ecc3c8d19774e9143173ad11af12.tar.bz2 linux-3.10-d614a64a0193ecc3c8d19774e9143173ad11af12.zip | |
USB: mos7840: fix race in register handling
commit d8a083cc746664916d9d36ed9e4d08a29525f245 upstream.
Fix race in mos7840_get_reg which unconditionally manipulated the
control urb (which may already be in use) by adding a control-urb busy
flag.
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/usb/serial/mos7840.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c index 62b86a68508..4bf9223f924 100644 --- a/drivers/usb/serial/mos7840.c +++ b/drivers/usb/serial/mos7840.c @@ -183,6 +183,10 @@ #define LED_ON_MS 500 #define LED_OFF_MS 500 +enum mos7840_flag { + MOS7840_FLAG_CTRL_BUSY, +}; + static int device_type; static const struct usb_device_id id_table[] = { @@ -241,6 +245,8 @@ struct moschip_port { bool led_flag; struct timer_list led_timer1; /* Timer for LED on */ struct timer_list led_timer2; /* Timer for LED off */ + + unsigned long flags; }; /* @@ -467,10 +473,10 @@ static void mos7840_control_callback(struct urb *urb) case -ESHUTDOWN: /* this urb is terminated, clean up */ dev_dbg(dev, "%s - urb shutting down with status: %d\n", __func__, status); - return; + goto out; default: dev_dbg(dev, "%s - nonzero urb status received: %d\n", __func__, status); - return; + goto out; } dev_dbg(dev, "%s urb buffer size is %d\n", __func__, urb->actual_length); @@ -483,6 +489,8 @@ static void mos7840_control_callback(struct urb *urb) mos7840_handle_new_msr(mos7840_port, regval); else if (mos7840_port->MsrLsr == 1) mos7840_handle_new_lsr(mos7840_port, regval); +out: + clear_bit_unlock(MOS7840_FLAG_CTRL_BUSY, &mos7840_port->flags); } static int mos7840_get_reg(struct moschip_port *mcs, __u16 Wval, __u16 reg, @@ -493,6 +501,9 @@ static int mos7840_get_reg(struct moschip_port *mcs, __u16 Wval, __u16 reg, unsigned char *buffer = mcs->ctrl_buf; int ret; + if (test_and_set_bit_lock(MOS7840_FLAG_CTRL_BUSY, &mcs->flags)) + return -EBUSY; + dr->bRequestType = MCS_RD_RTYPE; dr->bRequest = MCS_RDREQ; dr->wValue = cpu_to_le16(Wval); /* 0 */ @@ -504,6 +515,9 @@ static int mos7840_get_reg(struct moschip_port *mcs, __u16 Wval, __u16 reg, mos7840_control_callback, mcs); mcs->control_urb->transfer_buffer_length = 2; ret = usb_submit_urb(mcs->control_urb, GFP_ATOMIC); + if (ret) + clear_bit_unlock(MOS7840_FLAG_CTRL_BUSY, &mcs->flags); + return ret; } |