From 97f26ff6049a7fff5460cebe392ad1d699dc434c Mon Sep 17 00:00:00 2001
From: Mike Isely <isely@pobox.com>
Date: Mon, 7 Apr 2008 02:22:43 -0300
Subject: [PATCH] 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 <isely@pobox.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
---
drivers/media/video/pvrusb2/pvrusb2-hdw.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/media/video/pvrusb2/pvrusb2-hdw.c b/drivers/media/video/pvrusb2/pvrusb2-hdw.c
index 4f6bb58ca5fc8..f907a56c587d1 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;
}
--
2.30.2