diff options
| author | Anil Kaushik <anilkaushikwireless@gmail.com> | 2026-10-16 09:32:23 +0000 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2026-10-21 11:37:08 +0200 |
| commit | fe3e1a42fb7eb18d8c55d714b50a3d51f8cd6ffe (patch) | |
| tree | 66876c0729327367d78b0c2ce68d1d78ae09ef2f | |
| parent | 758d8928d2c5d6703da827577cef86d643155236 (diff) | |
gtp: hold RCU for the device lookup when adding a PDP context
gtp_genl_new_pdp() calls gtp_find_dev(), which looks the device up with
dev_get_by_index_rcu(). Since commit e2d1baca2b33 ("gtp: remove useless
rcu_read_lock()"), this only runs under the rtnl lock, and kernels with
CONFIG_PROVE_RCU_LIST warn:
WARNING: suspicious RCU usage
net/core/dev.c:1047 RCU-list traversed in non-reader section!!
...
dev_get_by_index_rcu
gtp_find_dev
gtp_genl_new_pdp
Hold the RCU read lock around the lookup only: gtp_pdp_add() allocates
with GFP_KERNEL, and the rtnl lock keeps the device alive afterwards.
Found with the gtp selftest on a debug kernel.
Fixes: e2d1baca2b33 ("gtp: remove useless rcu_read_lock()")
Signed-off-by: Anil Kaushik <anilkaushikwireless@gmail.com>
Link: https://patch.msgid.link/20261016093225.1036375-3-anilkaushikwireless@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
| -rw-r--r-- | drivers/net/gtp.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c index 99836b773e5c..15b5d845fc3b 100644 --- a/drivers/net/gtp.c +++ b/drivers/net/gtp.c @@ -2050,7 +2050,10 @@ static int gtp_genl_new_pdp(struct sk_buff *skb, struct genl_info *info) rtnl_lock(); + /* the rtnl lock keeps the device alive once found */ + rcu_read_lock(); gtp = gtp_find_dev(sock_net(skb->sk), info->attrs); + rcu_read_unlock(); if (!gtp) { err = -ENODEV; goto out_unlock; |