From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- net/ipv6/fib6_notifier.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) create mode 100644 net/ipv6/fib6_notifier.c (limited to 'net/ipv6/fib6_notifier.c') diff --git a/net/ipv6/fib6_notifier.c b/net/ipv6/fib6_notifier.c new file mode 100644 index 000000000..64cd4ed88 --- /dev/null +++ b/net/ipv6/fib6_notifier.c @@ -0,0 +1,65 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include +#include +#include +#include + +int call_fib6_notifier(struct notifier_block *nb, + enum fib_event_type event_type, + struct fib_notifier_info *info) +{ + info->family = AF_INET6; + return call_fib_notifier(nb, event_type, info); +} + +int call_fib6_notifiers(struct net *net, enum fib_event_type event_type, + struct fib_notifier_info *info) +{ + info->family = AF_INET6; + return call_fib_notifiers(net, event_type, info); +} + +static unsigned int fib6_seq_read(const struct net *net) +{ + return fib6_tables_seq_read(net) + fib6_rules_seq_read(net); +} + +static int fib6_dump(struct net *net, struct notifier_block *nb, + struct netlink_ext_ack *extack) +{ + int err; + + err = fib6_rules_dump(net, nb, extack); + if (err) + return err; + + return fib6_tables_dump(net, nb, extack); +} + +static const struct fib_notifier_ops fib6_notifier_ops_template = { + .family = AF_INET6, + .fib_seq_read = fib6_seq_read, + .fib_dump = fib6_dump, + .owner = THIS_MODULE, +}; + +int __net_init fib6_notifier_init(struct net *net) +{ + struct fib_notifier_ops *ops; + + ops = fib_notifier_ops_register(&fib6_notifier_ops_template, net); + if (IS_ERR(ops)) + return PTR_ERR(ops); + net->ipv6.notifier_ops = ops; + + return 0; +} + +void __net_exit fib6_notifier_exit(struct net *net) +{ + fib_notifier_ops_unregister(net->ipv6.notifier_ops); +} -- cgit v1.3.1