diff options
| author | Dongliang Mu <mudongliangabcd@gmail.com> | 2022-01-22 15:44:59 +0800 |
|---|---|---|
| committer | Hans Verkuil <hverkuil-cisco@xs4all.nl> | 2022-02-22 09:41:11 +0100 |
| commit | c08eadca1bdfa099e20a32f8fa4b52b2f672236d (patch) | |
| tree | f4aae9938eea814aa9b98f8733ae75499a0c30cb | |
| parent | dca4f5fdbcd7dddcd2169be2c3bf3057d51b100e (diff) | |
| download | linux-c08eadca1bdfa099e20a32f8fa4b52b2f672236d.tar.bz2 | |
media: em28xx: initialize refcount before kref_get
The commit 47677e51e2a4("[media] em28xx: Only deallocate struct
em28xx after finishing all extensions") adds kref_get to many init
functions (e.g., em28xx_audio_init). However, kref_init is called too
late in em28xx_usb_probe, since em28xx_init_dev before will invoke
those init functions and call kref_get function. Then refcount bug
occurs in my local syzkaller instance.
Fix it by moving kref_init before em28xx_init_dev. This issue occurs
not only in dev but also dev->dev_next.
Fixes: 47677e51e2a4 ("[media] em28xx: Only deallocate struct em28xx after finishing all extensions")
Reported-by: syzkaller <syzkaller@googlegroups.com>
Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
| -rw-r--r-- | drivers/media/usb/em28xx/em28xx-cards.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c index b451ce3cb169..f3b56c065ee1 100644 --- a/drivers/media/usb/em28xx/em28xx-cards.c +++ b/drivers/media/usb/em28xx/em28xx-cards.c @@ -3936,6 +3936,8 @@ static int em28xx_usb_probe(struct usb_interface *intf, goto err_free; } + kref_init(&dev->ref); + dev->devno = nr; dev->model = id->driver_info; dev->alt = -1; @@ -4036,6 +4038,8 @@ static int em28xx_usb_probe(struct usb_interface *intf, } if (dev->board.has_dual_ts && em28xx_duplicate_dev(dev) == 0) { + kref_init(&dev->dev_next->ref); + dev->dev_next->ts = SECONDARY_TS; dev->dev_next->alt = -1; dev->dev_next->is_audio_only = has_vendor_audio && @@ -4090,12 +4094,8 @@ static int em28xx_usb_probe(struct usb_interface *intf, em28xx_write_reg(dev, 0x0b, 0x82); mdelay(100); } - - kref_init(&dev->dev_next->ref); } - kref_init(&dev->ref); - request_modules(dev); /* |