From: Lin Ma linma@zju.edu.cn
[ Upstream commit afe7116f6d3b888778ed6d95e3cf724767b9aedf ]
There is a possible race condition (use-after-free) like below
(FREE) | (USE) adf7242_remove | adf7242_channel cancel_delayed_work_sync | destroy_workqueue (1) | adf7242_cmd_rx | mod_delayed_work (2) |
The root cause for this race is that the upper layer (ieee802154) is unaware of this detaching event and the function adf7242_channel can be called without any checks.
To fix this, we can add a flag write at the beginning of adf7242_remove and add flag check in adf7242_channel. Or we can just defer the destructive operation like other commit 3e0588c291d6 ("hamradio: defer ax25 kfree after unregister_netdev") which let the ieee802154_unregister_hw() to handle the synchronization. This patch takes the second option.
Fixes: 58e9683d1475 ("net: ieee802154: adf7242: Fix OCL calibration runs") Signed-off-by: Lin Ma linma@zju.edu.cn Acked-by: Michael Hennerich michael.hennerich@analog.com Link: https://lore.kernel.org/r/20220808034224.12642-1-linma@zju.edu.cn Signed-off-by: Stefan Schmidt stefan@datenfreihafen.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ieee802154/adf7242.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ieee802154/adf7242.c b/drivers/net/ieee802154/adf7242.c index 6afdf1622944e..5cf218c674a5a 100644 --- a/drivers/net/ieee802154/adf7242.c +++ b/drivers/net/ieee802154/adf7242.c @@ -1310,10 +1310,11 @@ static void adf7242_remove(struct spi_device *spi)
debugfs_remove_recursive(lp->debugfs_root);
+ ieee802154_unregister_hw(lp->hw); + cancel_delayed_work_sync(&lp->work); destroy_workqueue(lp->wqueue);
- ieee802154_unregister_hw(lp->hw); mutex_destroy(&lp->bmux); ieee802154_free_hw(lp->hw); }