From 31f1dabb4b9727b300ddaa2801903ae4b72e4e1e Mon Sep 17 00:00:00 2001 From: Mieczyslaw Nalewaj Date: Fri, 1 Nov 2024 21:59:23 +0100 Subject: [PATCH] mac80211: compatibility with kernel 6.6.59 Fix genlmsg_multicast_allns() build error on kernel 6.6.59. Based on kernel patch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit?h=v6.6.59&id=e0f83d268974dab0361d11904dfc9acec53f96a6 Signed-off-by: Mieczyslaw Nalewaj Link: https://github.com/openwrt/openwrt/pull/16835 Signed-off-by: Hauke Mehrtens --- ...t_allns-build-error-on-kernel-6.6.59.patch | 169 ++++++++++++++++++ 1 file changed, 169 insertions(+) create mode 100644 package/kernel/mac80211/patches/build/236-fix-genlmsg_multicast_allns-build-error-on-kernel-6.6.59.patch diff --git a/package/kernel/mac80211/patches/build/236-fix-genlmsg_multicast_allns-build-error-on-kernel-6.6.59.patch b/package/kernel/mac80211/patches/build/236-fix-genlmsg_multicast_allns-build-error-on-kernel-6.6.59.patch new file mode 100644 index 0000000000..905bf8dfc1 --- /dev/null +++ b/package/kernel/mac80211/patches/build/236-fix-genlmsg_multicast_allns-build-error-on-kernel-6.6.59.patch @@ -0,0 +1,169 @@ +From e0f83d268974dab0361d11904dfc9acec53f96a6 Mon Sep 17 00:00:00 2001 +From: Eric Dumazet +Date: Fri, 11 Oct 2024 17:12:17 +0000 +Subject: [PATCH] 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] +[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 +Cc: James Chapman +Cc: Tom Parkin +Cc: Johannes Berg +Link: https://patch.msgid.link/20241011171217.3166614-1-edumazet@google.com +Signed-off-by: Jakub Kicinski +Signed-off-by: Sasha Levin +--- + drivers/target/target_core_user.c | 2 +- + include/net/genetlink.h | 3 +-- + net/l2tp/l2tp_netlink.c | 4 ++-- + net/netlink/genetlink.c | 28 ++++++++++++++-------------- + net/wireless/nl80211.c | 8 ++------ + 5 files changed, 20 insertions(+), 25 deletions(-) + +--- a/backport-include/net/genetlink.h ++++ b/backport-include/net/genetlink.h +@@ -150,7 +150,7 @@ int genlmsg_multicast(const struct genl_ + #define genlmsg_multicast_allns LINUX_BACKPORT(genlmsg_multicast_allns) + int backport_genlmsg_multicast_allns(const struct genl_family *family, + struct sk_buff *skb, u32 portid, +- unsigned int group, gfp_t flags); ++ unsigned int group); + + #define genl_family_attrbuf LINUX_BACKPORT(genl_family_attrbuf) + static inline struct nlattr **genl_family_attrbuf(struct genl_family *family) +--- a/compat/backport-genetlink.c ++++ b/compat/backport-genetlink.c +@@ -198,23 +198,23 @@ int genlmsg_multicast(const struct genl_ + } + EXPORT_SYMBOL_GPL(genlmsg_multicast); + +-static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group, +- gfp_t flags) ++static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group) + { + struct sk_buff *tmp; + struct net *net, *prev = NULL; + bool delivered = false; + int err; + ++ rcu_read_lock(); + for_each_net_rcu(net) { + if (prev) { +- tmp = skb_clone(skb, flags); ++ tmp = skb_clone(skb, GFP_ATOMIC); + if (!tmp) { + err = -ENOMEM; + goto error; + } + err = nlmsg_multicast(prev->genl_sock, tmp, +- portid, group, flags); ++ portid, group, GFP_ATOMIC); + if (!err) + delivered = true; + else if (err != -ESRCH) +@@ -223,25 +223,29 @@ static int genlmsg_mcast(struct sk_buff + + prev = net; + } ++ err = nlmsg_multicast(prev->genl_sock, skb, portid, group, GFP_ATOMIC); ++ ++ rcu_read_unlock(); + +- err = nlmsg_multicast(prev->genl_sock, skb, portid, group, flags); + if (!err) + delivered = true; + else if (err != -ESRCH) + return err; + return delivered ? 0 : -ESRCH; + error: ++ rcu_read_unlock(); ++ + kfree_skb(skb); + return err; + } + + int backport_genlmsg_multicast_allns(const struct genl_family *family, + struct sk_buff *skb, u32 portid, +- unsigned int group, gfp_t flags) ++ unsigned int group) + { + group = __backport_genl_group(family, group); + if (group == INVALID_GROUP) + return -EINVAL; +- return genlmsg_mcast(skb, portid, group, flags); ++ return genlmsg_mcast(skb, portid, group); + } + EXPORT_SYMBOL_GPL(backport_genlmsg_multicast_allns); +--- a/net/wireless/nl80211.c ++++ b/net/wireless/nl80211.c +@@ -17956,10 +17956,8 @@ void nl80211_common_reg_change_event(enu + + genlmsg_end(msg, hdr); + +- rcu_read_lock(); + genlmsg_multicast_allns(&nl80211_fam, msg, 0, +- NL80211_MCGRP_REGULATORY, GFP_ATOMIC); +- rcu_read_unlock(); ++ NL80211_MCGRP_REGULATORY); + + return; + +@@ -18692,10 +18690,8 @@ void nl80211_send_beacon_hint_event(stru + + genlmsg_end(msg, hdr); + +- rcu_read_lock(); + genlmsg_multicast_allns(&nl80211_fam, msg, 0, +- NL80211_MCGRP_REGULATORY, GFP_ATOMIC); +- rcu_read_unlock(); ++ NL80211_MCGRP_REGULATORY); + + return; + -- 2.30.2