diff options
| author | Dongliang Mu <mudongliangabcd@gmail.com> | 2022-01-22 10:44:59 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-04-15 15:14:45 +0300 |
| commit | 0113fa98a49a8e46a19b0ad80f29c904c6feec23 (patch) | |
| tree | b8e06e5503d969952ae6c521471dfeb186d07927 | |
| parent | 0c4b290f124ce174fdc21ddb0c34296496bc6111 (diff) | |
| download | linux-0113fa98a49a8e46a19b0ad80f29c904c6feec23.tar.xz | |
media: em28xx: initialize refcount before kref_get
[ Upstream commit c08eadca1bdfa099e20a32f8fa4b52b2f672236d ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -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 06da08f8efdb..c7f79d0f3883 100644 --- a/drivers/media/usb/em28xx/em28xx-cards.c +++ b/drivers/media/usb/em28xx/em28xx-cards.c @@ -3822,6 +3822,8 @@ 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; @@ -3922,6 +3924,8 @@ 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 && @@ -3976,12 +3980,8 @@ 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); /* |