From: Johan Hovold Date: Mon, 26 May 2014 17:23:15 +0000 (+0200) Subject: USB: usb_wwan: fix write and suspend race X-Git-Tag: v3.2.61~95 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=85296fc41103b19ff46fdb7392fb87fd95c91669 USB: usb_wwan: fix write and suspend race commit 170fad9e22df0063eba0701adb966786d7a4ec5a upstream. Fix race between write() and suspend() which could lead to writes being dropped (or I/O while suspended) if the device is runtime suspended while a write request is being processed. Specifically, suspend() releases the susp_lock after determining the device is idle but before setting the suspended flag, thus leaving a window where a concurrent write() can submit an urb. Fixes: 383cedc3bb43 ("USB: serial: full autosuspend support for the option driver") Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- diff --git a/drivers/usb/serial/usb_wwan.c b/drivers/usb/serial/usb_wwan.c index 7ccff6c16c44..bb2a713dda93 100644 --- a/drivers/usb/serial/usb_wwan.c +++ b/drivers/usb/serial/usb_wwan.c @@ -647,22 +647,19 @@ EXPORT_SYMBOL(usb_wwan_release); int usb_wwan_suspend(struct usb_serial *serial, pm_message_t message) { struct usb_wwan_intf_private *intfdata = serial->private; - int b; dbg("%s entered", __func__); + spin_lock_irq(&intfdata->susp_lock); if (PMSG_IS_AUTO(message)) { - spin_lock_irq(&intfdata->susp_lock); - b = intfdata->in_flight; - spin_unlock_irq(&intfdata->susp_lock); - - if (b) + if (intfdata->in_flight) { + spin_unlock_irq(&intfdata->susp_lock); return -EBUSY; + } } - - spin_lock_irq(&intfdata->susp_lock); intfdata->suspended = 1; spin_unlock_irq(&intfdata->susp_lock); + stop_read_write_urbs(serial); return 0;