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Commit | Line | Data |
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38f540a8 GKH |
1 | From acd2a847e7fee7df11817f67dba75a2802793e5d Mon Sep 17 00:00:00 2001 |
2 | From: Jiri Kosina <jkosina@suse.cz> | |
3 | Date: Sat, 20 Oct 2007 00:05:19 +0200 | |
4 | Subject: USB: usbserial - fix potential deadlock between write() and IRQ | |
5 | Message-ID: <20071102152622.GB7279@kroah.com> | |
6 | ||
7 | From: Jiri Kosina <jkosina@suse.cz> | |
8 | ||
9 | patch acd2a847e7fee7df11817f67dba75a2802793e5d in mainline. | |
10 | ||
11 | USB: usbserial - fix potential deadlock between write() and IRQ | |
12 | ||
13 | usb_serial_generic_write() doesn't disable interrupts when taking port->lock, | |
14 | and could therefore deadlock with usb_serial_generic_read_bulk_callback() | |
15 | being called from interrupt, taking the same lock. Fix it. | |
16 | ||
17 | Signed-off-by: Jiri Kosina <jkosina@suse.cz> | |
18 | Acked-by: Larry Finger <larry.finger@lwfinger.net> | |
19 | Cc: Marcin Slusarz <marcin.slusarz@gmail.com> | |
20 | Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> | |
21 | ||
22 | --- | |
23 | drivers/usb/serial/generic.c | 7 ++++--- | |
24 | 1 file changed, 4 insertions(+), 3 deletions(-) | |
25 | ||
26 | --- a/drivers/usb/serial/generic.c | |
27 | +++ b/drivers/usb/serial/generic.c | |
28 | @@ -190,14 +190,15 @@ int usb_serial_generic_write(struct usb_ | |
29 | ||
30 | /* only do something if we have a bulk out endpoint */ | |
31 | if (serial->num_bulk_out) { | |
32 | - spin_lock_bh(&port->lock); | |
33 | + unsigned long flags; | |
34 | + spin_lock_irqsave(&port->lock, flags); | |
35 | if (port->write_urb_busy) { | |
36 | - spin_unlock_bh(&port->lock); | |
37 | + spin_unlock_irqrestore(&port->lock, flags); | |
38 | dbg("%s - already writing", __FUNCTION__); | |
39 | return 0; | |
40 | } | |
41 | port->write_urb_busy = 1; | |
42 | - spin_unlock_bh(&port->lock); | |
43 | + spin_unlock_irqrestore(&port->lock, flags); | |
44 | ||
45 | count = (count > port->bulk_out_size) ? port->bulk_out_size : count; | |
46 |