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* [PATCH] media: mxl111sf: change mutex_init() location
@ 2021-07-30 21:38 Pavel Skripkin
  2021-08-15  8:37 ` Sean Young
  0 siblings, 1 reply; 10+ messages in thread
From: Pavel Skripkin @ 2021-07-30 21:38 UTC (permalink / raw)
  To: mkrufky, mchehab, crope
  Cc: linux-media, linux-kernel, Pavel Skripkin, syzbot+5ca0bf339f13c4243001

Syzbot reported, that mxl111sf_ctrl_msg() uses uninitialized
mutex. The problem was in wrong mutex_init() location.

Previous mutex_init(&state->msg_lock) call was in ->init() function, but
dvb_usbv2_init() has this order of calls:

	dvb_usbv2_init()
	  dvb_usbv2_adapter_init()
	    dvb_usbv2_adapter_frontend_init()
	      props->frontend_attach()

	  props->init()

Since mxl111sf_frontend_attach_atsc_mh() calls mxl111sf_ctrl_msg()
internally we need to initialize state->msg_lock in it to make lockdep
happy.

Reported-and-tested-by: syzbot+5ca0bf339f13c4243001@syzkaller.appspotmail.com
Fixes: 8572211842af ("[media] mxl111sf: convert to new DVB USB")
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
---
 drivers/media/usb/dvb-usb-v2/mxl111sf.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/media/usb/dvb-usb-v2/mxl111sf.c b/drivers/media/usb/dvb-usb-v2/mxl111sf.c
index 7865fa0a8295..2e5663ffa7ce 100644
--- a/drivers/media/usb/dvb-usb-v2/mxl111sf.c
+++ b/drivers/media/usb/dvb-usb-v2/mxl111sf.c
@@ -931,8 +931,6 @@ static int mxl111sf_init(struct dvb_usb_device *d)
 		  .len = sizeof(eeprom), .buf = eeprom },
 	};
 
-	mutex_init(&state->msg_lock);
-
 	ret = get_chip_info(state);
 	if (mxl_fail(ret))
 		pr_err("failed to get chip info during probe");
@@ -979,8 +977,12 @@ static int mxl111sf_frontend_attach_mh(struct dvb_usb_adapter *adap)
 static int mxl111sf_frontend_attach_atsc_mh(struct dvb_usb_adapter *adap)
 {
 	int ret;
+	struct mxl111sf_state *state = d_to_priv(adap_to_d(adap));
+
 	pr_debug("%s\n", __func__);
 
+	mutex_init(&state->msg_lock);
+
 	ret = mxl111sf_lgdt3305_frontend_attach(adap, 0);
 	if (ret < 0)
 		return ret;
-- 
2.32.0


^ permalink raw reply	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2021-09-15 16:40 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-07-30 21:38 [PATCH] media: mxl111sf: change mutex_init() location Pavel Skripkin
2021-08-15  8:37 ` Sean Young
2021-08-15  8:49   ` Pavel Skripkin
2021-08-15  9:06     ` Pavel Skripkin
2021-08-19  9:29       ` Sean Young
2021-08-19  9:31         ` Pavel Skripkin
2021-08-19 10:38         ` [PATCH v2] " Pavel Skripkin
2021-08-19 10:42           ` [PATCH v3] " Pavel Skripkin
2021-09-12 15:49             ` Pavel Skripkin
2021-09-15 16:40               ` Sean Young

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