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| author | Eric Dumazet <edumazet@google.com> | 2025-08-12 14:32:06 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-08-20 18:30:56 +0200 |
| commit | 4ceb0bd4ffd009821b585ce6a8033b12b59fb5fb (patch) | |
| tree | 62c2ce81e9d550c2de805e2280ef8d1ab34bfbec /net/netlink | |
| parent | 2b260dc923e8b77f700d9f990c074449c67ee0cb (diff) | |
| download | linux-4ceb0bd4ffd009821b585ce6a8033b12b59fb5fb.tar.gz linux-4ceb0bd4ffd009821b585ce6a8033b12b59fb5fb.tar.bz2 linux-4ceb0bd4ffd009821b585ce6a8033b12b59fb5fb.zip | |
net: better track kernel sockets lifetime
[ Upstream commit 5c70eb5c593d64d93b178905da215a9fd288a4b5 ]
While kernel sockets are dismantled during pernet_operations->exit(),
their freeing can be delayed by any tx packets still held in qdisc
or device queues, due to skb_set_owner_w() prior calls.
This then trigger the following warning from ref_tracker_dir_exit() [1]
To fix this, make sure that kernel sockets own a reference on net->passive.
Add sk_net_refcnt_upgrade() helper, used whenever a kernel socket
is converted to a refcounted one.
[1]
[ 136.263918][ T35] ref_tracker: net notrefcnt@ffff8880638f01e0 has 1/2 users at
[ 136.263918][ T35] sk_alloc+0x2b3/0x370
[ 136.263918][ T35] inet6_create+0x6ce/0x10f0
[ 136.263918][ T35] __sock_create+0x4c0/0xa30
[ 136.263918][ T35] inet_ctl_sock_create+0xc2/0x250
[ 136.263918][ T35] igmp6_net_init+0x39/0x390
[ 136.263918][ T35] ops_init+0x31e/0x590
[ 136.263918][ T35] setup_net+0x287/0x9e0
[ 136.263918][ T35] copy_net_ns+0x33f/0x570
[ 136.263918][ T35] create_new_namespaces+0x425/0x7b0
[ 136.263918][ T35] unshare_nsproxy_namespaces+0x124/0x180
[ 136.263918][ T35] ksys_unshare+0x57d/0xa70
[ 136.263918][ T35] __x64_sys_unshare+0x38/0x40
[ 136.263918][ T35] do_syscall_64+0xf3/0x230
[ 136.263918][ T35] entry_SYSCALL_64_after_hwframe+0x77/0x7f
[ 136.263918][ T35]
[ 136.343488][ T35] ref_tracker: net notrefcnt@ffff8880638f01e0 has 1/2 users at
[ 136.343488][ T35] sk_alloc+0x2b3/0x370
[ 136.343488][ T35] inet6_create+0x6ce/0x10f0
[ 136.343488][ T35] __sock_create+0x4c0/0xa30
[ 136.343488][ T35] inet_ctl_sock_create+0xc2/0x250
[ 136.343488][ T35] ndisc_net_init+0xa7/0x2b0
[ 136.343488][ T35] ops_init+0x31e/0x590
[ 136.343488][ T35] setup_net+0x287/0x9e0
[ 136.343488][ T35] copy_net_ns+0x33f/0x570
[ 136.343488][ T35] create_new_namespaces+0x425/0x7b0
[ 136.343488][ T35] unshare_nsproxy_namespaces+0x124/0x180
[ 136.343488][ T35] ksys_unshare+0x57d/0xa70
[ 136.343488][ T35] __x64_sys_unshare+0x38/0x40
[ 136.343488][ T35] do_syscall_64+0xf3/0x230
[ 136.343488][ T35] entry_SYSCALL_64_after_hwframe+0x77/0x7f
Fixes: 0cafd77dcd03 ("net: add a refcount tracker for kernel sockets")
Reported-by: syzbot+30a19e01a97420719891@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/67b72aeb.050a0220.14d86d.0283.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250220131854.4048077-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/netlink')
| -rw-r--r-- | net/netlink/af_netlink.c | 10 |
1 files changed, 0 insertions, 10 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index e5ca84fb0073..8b060465a2be 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -794,16 +794,6 @@ static int netlink_release(struct socket *sock) sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1); - /* Because struct net might disappear soon, do not keep a pointer. */ - if (!sk->sk_net_refcnt && sock_net(sk) != &init_net) { - __netns_tracker_free(sock_net(sk), &sk->ns_tracker, false); - /* Because of deferred_put_nlk_sk and use of work queue, - * it is possible netns will be freed before this socket. - */ - sock_net_set(sk, &init_net); - __netns_tracker_alloc(&init_net, &sk->ns_tracker, - false, GFP_KERNEL); - } call_rcu(&nlk->rcu, deferred_put_nlk_sk); return 0; } |