From: Mike Isely Date: Mon, 7 Apr 2008 05:22:43 +0000 (-0300) Subject: V4L/DVB (7712): pvrusb2: Close connect/disconnect race X-Git-Tag: v2.6.26-rc1~1084^2~17 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=97f26ff6049a7fff5460cebe392ad1d699dc434c;p=linux-2.6-omap-h63xx.git V4L/DVB (7712): pvrusb2: Close connect/disconnect race If a disconnect happens before initialization is completed, the pvrusb2 driver can accidentally touch dangling pointers. The whole initialization function must be protected by the big_lock, and once inside that lock, the initialization function should abort if it is discovered that a disconnect has already taken place. Signed-off-by: Mike Isely Signed-off-by: Mauro Carvalho Chehab --- diff --git a/drivers/media/video/pvrusb2/pvrusb2-hdw.c b/drivers/media/video/pvrusb2/pvrusb2-hdw.c index 4f6bb58ca5f..f907a56c587 100644 --- a/drivers/media/video/pvrusb2/pvrusb2-hdw.c +++ b/drivers/media/video/pvrusb2/pvrusb2-hdw.c @@ -1854,10 +1854,19 @@ int pvr2_hdw_initialize(struct pvr2_hdw *hdw, void *callback_data) { LOCK_TAKE(hdw->big_lock); do { + if (hdw->flag_disconnected) { + /* Handle a race here: If we're already + disconnected by this point, then give up. If we + get past this then we'll remain connected for + the duration of initialization since the entire + initialization sequence is now protected by the + big_lock. */ + break; + } hdw->state_data = callback_data; hdw->state_func = callback_func; + pvr2_hdw_setup(hdw); } while (0); LOCK_GIVE(hdw->big_lock); - pvr2_hdw_setup(hdw); return hdw->flag_init_ok; }