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authorxiao jin <jin.xiao@intel.com>2014-05-26 19:23:14 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-05-27 15:04:05 -0700
commitd9e93c08d8d985e5ef89436ebc9f4aad7e31559f (patch)
tree61973a4cbc9d7b0fb935f3926dab842196c59425 /drivers/usb/serial
parentdb0904737947d509844e171c9863ecc5b4534005 (diff)
downloadlinux-stericsson-d9e93c08d8d985e5ef89436ebc9f4aad7e31559f.tar.gz
USB: usb_wwan: fix race between write and resume
We find a race between write and resume. usb_wwan_resume run play_delayed() and spin_unlock, but intfdata->suspended still is not set to zero. At this time usb_wwan_write is called and anchor the urb to delay list. Then resume keep running but the delayed urb have no chance to be commit until next resume. If the time of next resume is far away, tty will be blocked in tty_wait_until_sent during time. The race also can lead to writes being reordered. This patch put play_Delayed and intfdata->suspended together in the spinlock, it's to avoid the write race during resume. Fixes: 383cedc3bb43 ("USB: serial: full autosuspend support for the option driver") Signed-off-by: xiao jin <jin.xiao@intel.com> Signed-off-by: Zhang, Qi1 <qi1.zhang@intel.com> Reviewed-by: David Cohen <david.a.cohen@linux.intel.com> Cc: <stable@vger.kernel.org> # v2.6.32 Signed-off-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/serial')
-rw-r--r--drivers/usb/serial/usb_wwan.c8
1 files changed, 2 insertions, 6 deletions
diff --git a/drivers/usb/serial/usb_wwan.c b/drivers/usb/serial/usb_wwan.c
index 47ad7550c5a6..112693a4100b 100644
--- a/drivers/usb/serial/usb_wwan.c
+++ b/drivers/usb/serial/usb_wwan.c
@@ -660,17 +660,15 @@ int usb_wwan_resume(struct usb_serial *serial)
}
}
+ spin_lock_irq(&intfdata->susp_lock);
for (i = 0; i < serial->num_ports; i++) {
/* walk all ports */
port = serial->port[i];
portdata = usb_get_serial_port_data(port);
/* skip closed ports */
- spin_lock_irq(&intfdata->susp_lock);
- if (!portdata || !portdata->opened) {
- spin_unlock_irq(&intfdata->susp_lock);
+ if (!portdata || !portdata->opened)
continue;
- }
for (j = 0; j < N_IN_URB; j++) {
urb = portdata->in_urbs[j];
@@ -683,9 +681,7 @@ int usb_wwan_resume(struct usb_serial *serial)
}
}
play_delayed(port);
- spin_unlock_irq(&intfdata->susp_lock);
}
- spin_lock_irq(&intfdata->susp_lock);
intfdata->suspended = 0;
spin_unlock_irq(&intfdata->susp_lock);
err_out: