linux-stable.git/net/l2tp, branch v6.17 Linux kernel stable tree l2tp: do not use sock_hold() in pppol2tp_session_get_sock() 2025-08-28T00:16:13+00:00 Eric Dumazet edumazet@google.com 2025-08-26T13:44:35+00:00 9b8c88f875c04d4cb9111bd5dd9291c7e9691bf5 pppol2tp_session_get_sock() is using RCU, it must be ready for sk_refcnt being zero. Commit ee40fb2e1eb5 ("l2tp: protect sock pointer of struct pppol2tp_session with RCU") was correct because it had a call_rcu(..., pppol2tp_put_sk) which was later removed in blamed commit. pppol2tp_recv() can use pppol2tp_session_get_sock() as well. Fixes: c5cbaef992d6 ("l2tp: refactor ppp socket/session relationship") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: James Chapman <jchapman@katalix.com> Reviewed-by: Guillaume Nault <gnault@redhat.com> Link: https://patch.msgid.link/20250826134435.1683435-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
pppol2tp_session_get_sock() is using RCU, it must be ready
for sk_refcnt being zero.

Commit ee40fb2e1eb5 ("l2tp: protect sock pointer of
struct pppol2tp_session with RCU") was correct because it
had a call_rcu(..., pppol2tp_put_sk) which was later removed in blamed commit.

pppol2tp_recv() can use pppol2tp_session_get_sock() as well.

Fixes: c5cbaef992d6 ("l2tp: refactor ppp socket/session relationship")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: James Chapman <jchapman@katalix.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Link: https://patch.msgid.link/20250826134435.1683435-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: annotate races around sk->sk_uid 2025-06-24T00:04:03+00:00 Eric Dumazet edumazet@google.com 2025-06-20T13:30:00+00:00 e84a4927a404f369c842c19de93b216627fcc690 sk->sk_uid can be read while another thread changes its value in sockfs_setattr(). Add sk_uid(const struct sock *sk) helper to factorize the needed READ_ONCE() annotations, and add corresponding WRITE_ONCE() where needed. Fixes: 86741ec25462 ("net: core: Add a UID field to struct sock.") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Lorenzo Colitti <lorenzo@google.com> Reviewed-by: Maciej Żenczykowski <maze@google.com> Link: https://patch.msgid.link/20250620133001.4090592-2-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
sk->sk_uid can be read while another thread changes its
value in sockfs_setattr().

Add sk_uid(const struct sock *sk) helper to factorize the needed
READ_ONCE() annotations, and add corresponding WRITE_ONCE()
where needed.

Fixes: 86741ec25462 ("net: core: Add a UID field to struct sock.")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Lorenzo Colitti <lorenzo@google.com>
Reviewed-by: Maciej Żenczykowski <maze@google.com>
Link: https://patch.msgid.link/20250620133001.4090592-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: move misc netdev_lock flavors to a separate header 2025-03-08T17:06:50+00:00 Jakub Kicinski kuba@kernel.org 2025-03-07T18:30:06+00:00 8ef890df4031121a94407c84659125cbccd3fdbe Move the more esoteric helpers for netdev instance lock to a dedicated header. This avoids growing netdevice.h to infinity and makes rebuilding the kernel much faster (after touching the header with the helpers). The main netdev_lock() / netdev_unlock() functions are used in static inlines in netdevice.h and will probably be used most commonly, so keep them in netdevice.h. Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250307183006.2312761-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Move the more esoteric helpers for netdev instance lock to
a dedicated header. This avoids growing netdevice.h to infinity
and makes rebuilding the kernel much faster (after touching
the header with the helpers).

The main netdev_lock() / netdev_unlock() functions are used
in static inlines in netdevice.h and will probably be used
most commonly, so keep them in netdevice.h.

Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250307183006.2312761-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
ppp: use IFF_NO_QUEUE in virtual interfaces 2025-03-05T01:11:17+00:00 Qingfang Deng dqfext@gmail.com 2025-03-01T13:55:16+00:00 95d0d094ba26432ec467e2260f4bf553053f1f8f For PPPoE, PPTP, and PPPoL2TP, the start_xmit() function directly forwards packets to the underlying network stack and never returns anything other than 1. So these interfaces do not require a qdisc, and the IFF_NO_QUEUE flag should be set. Introduces a direct_xmit flag in struct ppp_channel to indicate when IFF_NO_QUEUE should be applied. The flag is set in ppp_connect_channel() for relevant protocols. While at it, remove the usused latency member from struct ppp_channel. Signed-off-by: Qingfang Deng <dqfext@gmail.com> Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://patch.msgid.link/20250301135517.695809-1-dqfext@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
For PPPoE, PPTP, and PPPoL2TP, the start_xmit() function directly
forwards packets to the underlying network stack and never returns
anything other than 1. So these interfaces do not require a qdisc,
and the IFF_NO_QUEUE flag should be set.

Introduces a direct_xmit flag in struct ppp_channel to indicate when
IFF_NO_QUEUE should be applied. The flag is set in ppp_connect_channel()
for relevant protocols.

While at it, remove the usused latency member from struct ppp_channel.

Signed-off-by: Qingfang Deng <dqfext@gmail.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://patch.msgid.link/20250301135517.695809-1-dqfext@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
ipv6: replace ipcm6_init calls with ipcm6_init_sk 2025-02-19T02:27:20+00:00 Willem de Bruijn willemb@google.com 2025-02-14T22:27:03+00:00 096208592b09c2f5fc0c1a174694efa41c04209d This initializes tclass and dontfrag before cmsg parsing, removing the need for explicit checks against -1 in each caller. Leave hlimit set to -1, because its full initialization (in ip6_sk_dst_hoplimit) requires more state (dst, flowi6, ..). This also prepares for calling sockcm_init in a follow-on patch. Signed-off-by: Willem de Bruijn <willemb@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://patch.msgid.link/20250214222720.3205500-7-willemdebruijn.kernel@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
This initializes tclass and dontfrag before cmsg parsing, removing the
need for explicit checks against -1 in each caller.

Leave hlimit set to -1, because its full initialization
(in ip6_sk_dst_hoplimit) requires more state (dst, flowi6, ..).

This also prepares for calling sockcm_init in a follow-on patch.

Signed-off-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20250214222720.3205500-7-willemdebruijn.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
l2tp: Use inet_sk_init_flowi4() in l2tp_ip_sendmsg(). 2024-12-20T21:50:09+00:00 Guillaume Nault gnault@redhat.com 2024-12-16T17:21:54+00:00 c63e9f3b89d3f96220a1c99466fed4563c14a259 Use inet_sk_init_flowi4() to automatically initialise the flowi4 structure in l2tp_ip_sendmsg() instead of passing parameters manually to ip_route_output_ports(). Override ->daddr with the value passed in the msghdr structure if provided. Signed-off-by: Guillaume Nault <gnault@redhat.com> Reviewed-by: James Chapman <jchapman@katalix.com> Link: https://patch.msgid.link/2ff22a3560c5050228928456662b80b9c84a8fe4.1734357769.git.gnault@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Use inet_sk_init_flowi4() to automatically initialise the flowi4
structure in l2tp_ip_sendmsg() instead of passing parameters manually
to ip_route_output_ports().

Override ->daddr with the value passed in the msghdr structure if
provided.

Signed-off-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: James Chapman <jchapman@katalix.com>
Link: https://patch.msgid.link/2ff22a3560c5050228928456662b80b9c84a8fe4.1734357769.git.gnault@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
l2tp: Handle eth stats using NETDEV_PCPU_STAT_DSTATS. 2024-12-11T13:57:26+00:00 James Chapman jchapman@katalix.com 2024-12-09T11:46:07+00:00 c0b8980e6041afa363361e41fcafd7862721c3ee l2tp_eth uses the TSTATS infrastructure (dev_sw_netstats_*()) for RX and TX packet counters and DEV_STATS_INC for dropped counters. Consolidate that using the DSTATS infrastructure, which can handle both packet counters and packet drops. Statistics that don't fit DSTATS are still updated atomically with DEV_STATS_INC(). This change is inspired by the introduction of DSTATS helpers and their use in other udp tunnel drivers: Link: https://lore.kernel.org/all/cover.1733313925.git.gnault@redhat.com/ Signed-off-by: James Chapman <jchapman@katalix.com> Reviewed-by: Guillaume Nault <gnault@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
l2tp_eth uses the TSTATS infrastructure (dev_sw_netstats_*()) for RX
and TX packet counters and DEV_STATS_INC for dropped counters.

Consolidate that using the DSTATS infrastructure, which can
handle both packet counters and packet drops. Statistics that don't
fit DSTATS are still updated atomically with DEV_STATS_INC().

This change is inspired by the introduction of DSTATS helpers and
their use in other udp tunnel drivers:
Link: https://lore.kernel.org/all/cover.1733313925.git.gnault@redhat.com/

Signed-off-by: James Chapman <jchapman@katalix.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/l2tp: fix warning in l2tp_exit_net found by syzbot 2024-11-26T08:27:07+00:00 James Chapman jchapman@katalix.com 2024-11-18T14:04:11+00:00 5d066766c5f1252f98ff859265bcd1a5b52ac46c In l2tp's net exit handler, we check that an IDR is empty before destroying it: WARN_ON_ONCE(!idr_is_empty(&pn->l2tp_tunnel_idr)); idr_destroy(&pn->l2tp_tunnel_idr); By forcing memory allocation failures in idr_alloc_32, syzbot is able to provoke a condition where idr_is_empty returns false despite there being no items in the IDR. This turns out to be because the radix tree of the IDR contains only internal radix-tree nodes and it is this that causes idr_is_empty to return false. The internal nodes are cleaned by idr_destroy. Use idr_for_each to check that the IDR is empty instead of idr_is_empty to avoid the problem. Reported-by: syzbot+332fe1e67018625f63c9@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=332fe1e67018625f63c9 Fixes: 73d33bd063c4 ("l2tp: avoid using drain_workqueue in l2tp_pre_exit_net") Signed-off-by: James Chapman <jchapman@katalix.com> Link: https://patch.msgid.link/20241118140411.1582555-1-jchapman@katalix.com Signed-off-by: Paolo Abeni <pabeni@redhat.com> 
In l2tp's net exit handler, we check that an IDR is empty before
destroying it:

	WARN_ON_ONCE(!idr_is_empty(&pn->l2tp_tunnel_idr));
	idr_destroy(&pn->l2tp_tunnel_idr);

By forcing memory allocation failures in idr_alloc_32, syzbot is able
to provoke a condition where idr_is_empty returns false despite there
being no items in the IDR. This turns out to be because the radix tree
of the IDR contains only internal radix-tree nodes and it is this that
causes idr_is_empty to return false. The internal nodes are cleaned by
idr_destroy.

Use idr_for_each to check that the IDR is empty instead of
idr_is_empty to avoid the problem.

Reported-by: syzbot+332fe1e67018625f63c9@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=332fe1e67018625f63c9
Fixes: 73d33bd063c4 ("l2tp: avoid using drain_workqueue in l2tp_pre_exit_net")
Signed-off-by: James Chapman <jchapman@katalix.com>
Link: https://patch.msgid.link/20241118140411.1582555-1-jchapman@katalix.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
genetlink: hold RCU in genlmsg_mcast() 2024-10-16T00:52:58+00:00 Eric Dumazet edumazet@google.com 2024-10-11T17:12:17+00:00 56440d7ec28d60f8da3bfa09062b3368ff9b16db While running net selftests with CONFIG_PROVE_RCU_LIST=y I saw one lockdep splat [1]. genlmsg_mcast() uses for_each_net_rcu(), and must therefore hold RCU. Instead of letting all callers guard genlmsg_multicast_allns() with a rcu_read_lock()/rcu_read_unlock() pair, do it in genlmsg_mcast(). This also means the @flags parameter is useless, we need to always use GFP_ATOMIC. [1] [10882.424136] ============================= [10882.424166] WARNING: suspicious RCU usage [10882.424309] 6.12.0-rc2-virtme #1156 Not tainted [10882.424400] ----------------------------- [10882.424423] net/netlink/genetlink.c:1940 RCU-list traversed in non-reader section!! [10882.424469] other info that might help us debug this: [10882.424500] rcu_scheduler_active = 2, debug_locks = 1 [10882.424744] 2 locks held by ip/15677: [10882.424791] #0: ffffffffb6b491b0 (cb_lock){++++}-{3:3}, at: genl_rcv (net/netlink/genetlink.c:1219) [10882.426334] #1: ffffffffb6b49248 (genl_mutex){+.+.}-{3:3}, at: genl_rcv_msg (net/netlink/genetlink.c:61 net/netlink/genetlink.c:57 net/netlink/genetlink.c:1209) [10882.426465] stack backtrace: [10882.426805] CPU: 14 UID: 0 PID: 15677 Comm: ip Not tainted 6.12.0-rc2-virtme #1156 [10882.426919] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [10882.427046] Call Trace: [10882.427131] <TASK> [10882.427244] dump_stack_lvl (lib/dump_stack.c:123) [10882.427335] lockdep_rcu_suspicious (kernel/locking/lockdep.c:6822) [10882.427387] genlmsg_multicast_allns (net/netlink/genetlink.c:1940 (discriminator 7) net/netlink/genetlink.c:1977 (discriminator 7)) [10882.427436] l2tp_tunnel_notify.constprop.0 (net/l2tp/l2tp_netlink.c:119) l2tp_netlink [10882.427683] l2tp_nl_cmd_tunnel_create (net/l2tp/l2tp_netlink.c:253) l2tp_netlink [10882.427748] genl_family_rcv_msg_doit (net/netlink/genetlink.c:1115) [10882.427834] genl_rcv_msg (net/netlink/genetlink.c:1195 net/netlink/genetlink.c:1210) [10882.427877] ? __pfx_l2tp_nl_cmd_tunnel_create (net/l2tp/l2tp_netlink.c:186) l2tp_netlink [10882.427927] ? __pfx_genl_rcv_msg (net/netlink/genetlink.c:1201) [10882.427959] netlink_rcv_skb (net/netlink/af_netlink.c:2551) [10882.428069] genl_rcv (net/netlink/genetlink.c:1220) [10882.428095] netlink_unicast (net/netlink/af_netlink.c:1332 net/netlink/af_netlink.c:1357) [10882.428140] netlink_sendmsg (net/netlink/af_netlink.c:1901) [10882.428210] ____sys_sendmsg (net/socket.c:729 (discriminator 1) net/socket.c:744 (discriminator 1) net/socket.c:2607 (discriminator 1)) Fixes: 33f72e6f0c67 ("l2tp : multicast notification to the registered listeners") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: James Chapman <jchapman@katalix.com> Cc: Tom Parkin <tparkin@katalix.com> Cc: Johannes Berg <johannes.berg@intel.com> Link: https://patch.msgid.link/20241011171217.3166614-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
While running net selftests with CONFIG_PROVE_RCU_LIST=y I saw
one lockdep splat [1].

genlmsg_mcast() uses for_each_net_rcu(), and must therefore hold RCU.

Instead of letting all callers guard genlmsg_multicast_allns()
with a rcu_read_lock()/rcu_read_unlock() pair, do it in genlmsg_mcast().

This also means the @flags parameter is useless, we need to always use
GFP_ATOMIC.

[1]
[10882.424136] =============================
[10882.424166] WARNING: suspicious RCU usage
[10882.424309] 6.12.0-rc2-virtme #1156 Not tainted
[10882.424400] -----------------------------
[10882.424423] net/netlink/genetlink.c:1940 RCU-list traversed in non-reader section!!
[10882.424469]
other info that might help us debug this:

[10882.424500]
rcu_scheduler_active = 2, debug_locks = 1
[10882.424744] 2 locks held by ip/15677:
[10882.424791] #0: ffffffffb6b491b0 (cb_lock){++++}-{3:3}, at: genl_rcv (net/netlink/genetlink.c:1219)
[10882.426334] #1: ffffffffb6b49248 (genl_mutex){+.+.}-{3:3}, at: genl_rcv_msg (net/netlink/genetlink.c:61 net/netlink/genetlink.c:57 net/netlink/genetlink.c:1209)
[10882.426465]
stack backtrace:
[10882.426805] CPU: 14 UID: 0 PID: 15677 Comm: ip Not tainted 6.12.0-rc2-virtme #1156
[10882.426919] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[10882.427046] Call Trace:
[10882.427131]  <TASK>
[10882.427244] dump_stack_lvl (lib/dump_stack.c:123)
[10882.427335] lockdep_rcu_suspicious (kernel/locking/lockdep.c:6822)
[10882.427387] genlmsg_multicast_allns (net/netlink/genetlink.c:1940 (discriminator 7) net/netlink/genetlink.c:1977 (discriminator 7))
[10882.427436] l2tp_tunnel_notify.constprop.0 (net/l2tp/l2tp_netlink.c:119) l2tp_netlink
[10882.427683] l2tp_nl_cmd_tunnel_create (net/l2tp/l2tp_netlink.c:253) l2tp_netlink
[10882.427748] genl_family_rcv_msg_doit (net/netlink/genetlink.c:1115)
[10882.427834] genl_rcv_msg (net/netlink/genetlink.c:1195 net/netlink/genetlink.c:1210)
[10882.427877] ? __pfx_l2tp_nl_cmd_tunnel_create (net/l2tp/l2tp_netlink.c:186) l2tp_netlink
[10882.427927] ? __pfx_genl_rcv_msg (net/netlink/genetlink.c:1201)
[10882.427959] netlink_rcv_skb (net/netlink/af_netlink.c:2551)
[10882.428069] genl_rcv (net/netlink/genetlink.c:1220)
[10882.428095] netlink_unicast (net/netlink/af_netlink.c:1332 net/netlink/af_netlink.c:1357)
[10882.428140] netlink_sendmsg (net/netlink/af_netlink.c:1901)
[10882.428210] ____sys_sendmsg (net/socket.c:729 (discriminator 1) net/socket.c:744 (discriminator 1) net/socket.c:2607 (discriminator 1))

Fixes: 33f72e6f0c67 ("l2tp : multicast notification to the registered listeners")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: James Chapman <jchapman@katalix.com>
Cc: Tom Parkin <tparkin@katalix.com>
Cc: Johannes Berg <johannes.berg@intel.com>
Link: https://patch.msgid.link/20241011171217.3166614-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
l2tp: remove unneeded null check in l2tp_v2_session_get_next 2024-09-04T23:39:32+00:00 James Chapman jchapman@katalix.com 2024-09-03T11:35:47+00:00 510c0732fc8cabe7bca8de291c74d3f3cc36df48 Commit aa92c1cec92b ("l2tp: add tunnel/session get_next helpers") uses idr_get_next APIs to iterate over l2tp session IDR lists. Sessions in l2tp_v2_session_idr always have a non-null session->tunnel pointer since l2tp_session_register sets it before inserting the session into the IDR. Therefore the null check on session->tunnel in l2tp_v2_session_get_next is redundant and can be removed. Removing the check avoids a warning from lkp. Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/r/202408111407.HtON8jqa-lkp@intel.com/ CC: Dan Carpenter <dan.carpenter@linaro.org> Signed-off-by: James Chapman <jchapman@katalix.com> Acked-by: Tom Parkin <tparkin@katalix.com> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20240903113547.1261048-1-jchapman@katalix.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Commit aa92c1cec92b ("l2tp: add tunnel/session get_next helpers") uses
idr_get_next APIs to iterate over l2tp session IDR lists.  Sessions in
l2tp_v2_session_idr always have a non-null session->tunnel pointer
since l2tp_session_register sets it before inserting the session into
the IDR. Therefore the null check on session->tunnel in
l2tp_v2_session_get_next is redundant and can be removed. Removing the
check avoids a warning from lkp.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/r/202408111407.HtON8jqa-lkp@intel.com/
CC: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: James Chapman <jchapman@katalix.com>
Acked-by: Tom Parkin <tparkin@katalix.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20240903113547.1261048-1-jchapman@katalix.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>