linux-kernel - [PATCH bpf] bpf: add missing ops lock around dev_xdp_attach

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Message-ID: <20250331142814.1887506-1-sdf@fomichev.me>
Date: Mon, 31 Mar 2025 07:28:14 -0700
From: Stanislav Fomichev <sdf@...ichev.me>
To: bpf@...r.kernel.org,
	netdev@...r.kernel.org
Cc: ast@...nel.org,
	daniel@...earbox.net,
	andrii@...nel.org,
	martin.lau@...ux.dev,
	song@...nel.org,
	yhs@...com,
	john.fastabend@...il.com,
	kpsingh@...nel.org,
	haoluo@...gle.com,
	jolsa@...nel.org,
	linux-kernel@...r.kernel.org,
	davem@...emloft.net,
	edumazet@...gle.com,
	kuba@...nel.org,
	pabeni@...hat.com,
	horms@...nel.org,
	hawk@...nel.org,
	sdf@...ichev.me,
	syzbot+08936936fe8132f91f1a@...kaller.appspotmail.com
Subject: [PATCH bpf] bpf: add missing ops lock around dev_xdp_attach_link

Syzkaller points out that create_link path doesn't grab ops lock,
add it.

Cc: Jakub Kicinski <kuba@...nel.org>
Reported-by: syzbot+08936936fe8132f91f1a@...kaller.appspotmail.com
Closes: https://lore.kernel.org/bpf/67e6b3e8.050a0220.2f068f.0079.GAE@google.com/
Fixes: 97246d6d21c2 ("net: hold netdev instance lock during ndo_bpf")
Signed-off-by: Stanislav Fomichev <sdf@...ichev.me>
---
 net/core/dev.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/core/dev.c b/net/core/dev.c
index be17e0660144..5d20ff226d5e 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -10284,7 +10284,9 @@ int bpf_xdp_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
 		goto unlock;
 	}
 
+	netdev_lock_ops(dev);
 	err = dev_xdp_attach_link(dev, &extack, link);
+	netdev_unlock_ops(dev);
 	rtnl_unlock();
 
 	if (err) {
-- 
2.48.1