bianbu-linux-6.6/net/wireless
Eric Dumazet b94e5375ec genetlink: hold RCU in genlmsg_mcast()
[ Upstream commit 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: 33f72e6f0c ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-11-01 01:58:23 +01:00
..
certs wifi: cfg80211: fix certs build to not depend on file order 2024-01-01 12:42:39 +00:00
.gitignore
ap.c wifi: nl80211: add MLO_LINK_ID to CMD_STOP_AP event 2023-02-14 12:09:17 +01:00
chan.c wifi: cfg80211: move puncturing bitmap validation from mac80211 2023-02-14 12:09:18 +01:00
core.c wifi: cfg80211: fully move wiphy work to unbound workqueue 2024-06-21 14:38:12 +02:00
core.h Revert "wifi: cfg80211: check wiphy mutex is held for wdev mutex" 2024-09-30 16:25:14 +02:00
debugfs.c wifi: cfg80211: debugfs: fix return type in ht40allow_map_read() 2022-08-25 10:04:46 +02:00
debugfs.h
ethtool.c wifi: cfg80211: use strscpy to replace strlcpy 2022-07-15 11:43:12 +02:00
ibss.c wifi: cfg80211: remove support for static WEP 2023-01-18 17:31:44 +01:00
Kconfig
lib80211.c
lib80211_crypt_ccmp.c wifi: use struct_group to copy addresses 2022-09-03 16:40:06 +02:00
lib80211_crypt_tkip.c
lib80211_crypt_wep.c
Makefile
mesh.c
mlme.c wifi: cfg80211: fix assoc response warning on failed links 2023-10-23 13:25:30 +02:00
nl80211.c genetlink: hold RCU in genlmsg_mcast() 2024-11-01 01:58:23 +01:00
nl80211.h wifi: nl80211: Remove unused declaration nl80211_pmsr_dump_results() 2023-08-22 21:40:40 +02:00
ocb.c wifi: cfg80211: ocb: don't leave if not joined 2023-08-22 21:40:39 +02:00
of.c
pmsr.c wifi: cfg80211: pmsr: use correct nla_get_uX functions 2024-06-21 14:38:12 +02:00
radiotap.c
rdev-ops.h wifi: cfg80211: fix 6 GHz scan request building 2024-07-25 09:50:41 +02:00
reg.c wifi: nl80211/reg: add no-EHT regulatory flag 2023-06-21 14:01:29 +02:00
reg.h
scan.c wifi: cfg80211: fix UBSAN noise in cfg80211_wext_siwscan() 2024-10-04 16:28:56 +02:00
sme.c wifi: cfg80211: fix two more possible UBSAN-detected off-by-one errors 2024-10-04 16:28:57 +02:00
sysfs.c wifi: cfg80211: fully move wiphy work to unbound workqueue 2024-06-21 14:38:12 +02:00
sysfs.h
trace.c
trace.h wifi: cfg80211: fix the order of arguments for trace events of the tx_rx_evt class 2024-06-12 11:11:22 +02:00
util.c wifi: cfg80211: handle 2x996 RU allocation in cfg80211_calculate_bitrate_he() 2024-08-03 08:53:39 +02:00
wext-compat.c wifi: cfg80211: remove support for static WEP 2023-01-18 17:31:44 +01:00
wext-compat.h wifi: cfg80211: Avoid clashing function prototypes 2022-11-16 11:31:47 +02:00
wext-core.c wifi: cfg80211: add a flag to disable wireless extensions 2024-04-03 15:28:54 +02:00
wext-priv.c
wext-proc.c
wext-sme.c wifi: cfg80211: wext: hold wiphy lock in siwgenie 2023-06-07 19:53:11 +02:00
wext-spy.c