6.12-stable review patch. If anyone has any objections, please let me know.
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From: Ma Ke make24@iscas.ac.cn
commit 63ce53724637e2e7ba51fe3a4f78351715049905 upstream.
Using device_find_child() to locate a probed virtual-device-port node causes a device refcount imbalance, as device_find_child() internally calls get_device() to increment the device’s reference count before returning its pointer. vdc_port_mpgroup_check() directly returns true upon finding a matching device without releasing the reference via put_device(). We should call put_device() to decrement refcount.
As comment of device_find_child() says, 'NOTE: you will need to drop the reference with put_device() after use'.
Found by code review.
Cc: stable@vger.kernel.org Fixes: 3ee70591d6c4 ("sunvdc: prevent sunvdc panic when mpgroup disk added to guest domain") Signed-off-by: Ma Ke make24@iscas.ac.cn Link: https://lore.kernel.org/r/20250719075856.3447953-1-make24@iscas.ac.cn Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/block/sunvdc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/block/sunvdc.c +++ b/drivers/block/sunvdc.c @@ -957,8 +957,10 @@ static bool vdc_port_mpgroup_check(struc dev = device_find_child(vdev->dev.parent, &port_data, vdc_device_probed);
- if (dev) + if (dev) { + put_device(dev); return true; + }
return false; }