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authorPeter Beutner <p.beutner@gmx.net>2005-07-07 17:57:36 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2005-07-07 18:23:53 -0700
commit6757ccc57d2cc4ab4e63d8aee97f2e6b9f998990 (patch)
tree472bad3348464fa74910d6ac8978b6a63cb01a35 /drivers
parent25a26ec3b60b29300a652d7d81a69b6bc08b35b5 (diff)
[PATCH] dvb: core: fix race condition in FE_READ_STATUS ioctl
Fix a race condition where an application which issued a FE_READ_STATUS ioctl directly after FE_SET_FRONTEND would see an old status, i.e. FE_READ_STATUS would be executed before the frontend thread has even seen the tungin request from FE_SET_FRONTEND. Signed-off-by: Peter Beutner <p.beutner@gmx.net> Signed-off-by: Johannes Stezenbach <js@linuxtv.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/media/dvb/dvb-core/dvb_frontend.c16
1 files changed, 13 insertions, 3 deletions
diff --git a/drivers/media/dvb/dvb-core/dvb_frontend.c b/drivers/media/dvb/dvb-core/dvb_frontend.c
index f11daae91cd..e561ac1e1b1 100644
--- a/drivers/media/dvb/dvb-core/dvb_frontend.c
+++ b/drivers/media/dvb/dvb-core/dvb_frontend.c
@@ -626,11 +626,21 @@ static int dvb_frontend_ioctl(struct inode *inode, struct file *file,
break;
}
- case FE_READ_STATUS:
+ case FE_READ_STATUS: {
+ fe_status_t* status = parg;
+
+ /* if retune was requested but hasn't occured yet, prevent
+ * that user get signal state from previous tuning */
+ if(fepriv->state == FESTATE_RETUNE) {
+ err=0;
+ *status = 0;
+ break;
+ }
+
if (fe->ops->read_status)
- err = fe->ops->read_status(fe, (fe_status_t*) parg);
+ err = fe->ops->read_status(fe, status);
break;
-
+ }
case FE_READ_BER:
if (fe->ops->read_ber)
err = fe->ops->read_ber(fe, (__u32*) parg);