lkml.org 
[lkml]   [2010]   [Dec]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
FromOliver Neukum <>
SubjectRe: [PATCH] USB: USBHID: Fix race between disconnect and hiddev_ioctl
DateSat, 4 Dec 2010 21:22:23 +0100
Am Samstag, 4. Dezember 2010, 00:16:12 schrieb Dmitry Torokhov:
> > Since disconnect can happen at any time, we can't initialize
> > struct hid_device *hid = hiddev->hid at the beginning of ioctl
> > and then use it.
> >
> > This change checks hiddev->exist flag while holding
> > the existancelock and uses hid_device only if it exists.
>
> Why didn't you take the lock and check hiddev->exist at the beginning of
> ioctl handler instead of pushing it down into individual command
> handlers? I guess it would slow down HIDIOCGVERSION but I think we could
> pay this price for code that is more clear ;)

Strictly speaking you'd change the semantics. Right now you can execute
the ioctl even if you know you are holding an fd to a disconnected device
open.

Regards
Oliver


\
 
 \ /
  Last update: 2010-12-04 21:23    [from the cache]
©2003-2010