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authorxiao jin <jin.xiao@intel.com>2014-05-26 19:23:14 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-06-30 20:11:56 -0700
commit2f59a10cb390aaa74dda48ca73214d8ce52d3c2b (patch)
tree252f81ece728bac5f84c2dae6ad48412d5cc2164
parent2bcee6d0ec6d18fff28b36d230d3ecff1778ecc2 (diff)
USB: usb_wwan: fix race between write and resume
commit d9e93c08d8d985e5ef89436ebc9f4aad7e31559f upstream. 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> Signed-off-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-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 47ad7550c5a..112693a4100 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: