From 2e996ca81f9512c2d39d826a5146e5fe4ab28277 Mon Sep 17 00:00:00 2001 From: Yousef Alhouseen Date: Sun, 28 Jun 2026 02:28:04 +0200 Subject: netdevsim: remove ethtool debugfs files before freeing netdev The ethtool debugfs files point directly into struct netdevsim, which is allocated as net_device private data. Their containing port directory is removed only after nsim_destroy() calls free_netdev(). An open simple-attribute file can consequently dereference the freed private data before the directory is removed. KASAN observed this in debugfs_u32_get() during network namespace teardown. Track and remove the ethtool subtree before free_netdev() on both the normal and registration-failure paths. debugfs removal drains active file users before returning. Fixes: ff1f7c17fb20 ("netdevsim: add pause frame stats") Reported-by: syzbot+6c25f4750230faf70be9@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=6c25f4750230faf70be9 Cc: # netdevsim is a test harness, it's never loaded on production systems Signed-off-by: Yousef Alhouseen Link: https://patch.msgid.link/20260628002804.24214-1-alhouseenyousef@gmail.com Signed-off-by: Jakub Kicinski --- drivers/net/netdevsim/netdev.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/net/netdevsim/netdev.c') diff --git a/drivers/net/netdevsim/netdev.c b/drivers/net/netdevsim/netdev.c index 27e5f109f933..4e9d7e10b527 100644 --- a/drivers/net/netdevsim/netdev.c +++ b/drivers/net/netdevsim/netdev.c @@ -1165,6 +1165,7 @@ struct netdevsim *nsim_create(struct nsim_dev *nsim_dev, return ns; err_free_netdev: + nsim_ethtool_fini(ns); free_netdev(dev); return ERR_PTR(err); } @@ -1178,6 +1179,7 @@ void nsim_destroy(struct netdevsim *ns) debugfs_remove(ns->vlan_dfs); debugfs_remove(ns->qr_dfs); debugfs_remove(ns->pp_dfs); + nsim_ethtool_fini(ns); if (ns->nb.notifier_call) unregister_netdevice_notifier_dev_net(ns->netdev, &ns->nb, -- cgit v1.2.3