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From: Eric Dumazet <edumazet@google.com>
To: "David S . Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	 Paolo Abeni <pabeni@redhat.com>,
	Pablo Neira Ayuso <pablo@netfilter.org>,
	 Jozsef Kadlecsik <kadlec@netfilter.org>
Cc: netdev@vger.kernel.org, netfilter-devel@vger.kernel.org,
	 coreteam@netfilter.org, eric.dumazet@gmail.com,
	 Eric Dumazet <edumazet@google.com>,
	syzbot <syzkaller@googlegroups.com>
Subject: [PATCH net] netfilter: nfnetlink_queue: acquire rcu_read_lock() in instance_destroy_rcu()
Date: Wed, 15 May 2024 13:23:39 +0000	[thread overview]
Message-ID: <20240515132339.3346267-1-edumazet@google.com> (raw)

syzbot reported that nf_reinject() could be called without rcu_read_lock() :

WARNING: suspicious RCU usage
6.9.0-rc7-syzkaller-02060-g5c1672705a1a #0 Not tainted

net/netfilter/nfnetlink_queue.c:263 suspicious rcu_dereference_check() usage!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
2 locks held by syz-executor.4/13427:
  #0: ffffffff8e334f60 (rcu_callback){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
  #0: ffffffff8e334f60 (rcu_callback){....}-{0:0}, at: rcu_do_batch kernel/rcu/tree.c:2190 [inline]
  #0: ffffffff8e334f60 (rcu_callback){....}-{0:0}, at: rcu_core+0xa86/0x1830 kernel/rcu/tree.c:2471
  #1: ffff88801ca92958 (&inst->lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
  #1: ffff88801ca92958 (&inst->lock){+.-.}-{2:2}, at: nfqnl_flush net/netfilter/nfnetlink_queue.c:405 [inline]
  #1: ffff88801ca92958 (&inst->lock){+.-.}-{2:2}, at: instance_destroy_rcu+0x30/0x220 net/netfilter/nfnetlink_queue.c:172

stack backtrace:
CPU: 0 PID: 13427 Comm: syz-executor.4 Not tainted 6.9.0-rc7-syzkaller-02060-g5c1672705a1a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Call Trace:
 <IRQ>
  __dump_stack lib/dump_stack.c:88 [inline]
  dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
  lockdep_rcu_suspicious+0x221/0x340 kernel/locking/lockdep.c:6712
  nf_reinject net/netfilter/nfnetlink_queue.c:323 [inline]
  nfqnl_reinject+0x6ec/0x1120 net/netfilter/nfnetlink_queue.c:397
  nfqnl_flush net/netfilter/nfnetlink_queue.c:410 [inline]
  instance_destroy_rcu+0x1ae/0x220 net/netfilter/nfnetlink_queue.c:172
  rcu_do_batch kernel/rcu/tree.c:2196 [inline]
  rcu_core+0xafd/0x1830 kernel/rcu/tree.c:2471
  handle_softirqs+0x2d6/0x990 kernel/softirq.c:554
  __do_softirq kernel/softirq.c:588 [inline]
  invoke_softirq kernel/softirq.c:428 [inline]
  __irq_exit_rcu+0xf4/0x1c0 kernel/softirq.c:637
  irq_exit_rcu+0x9/0x30 kernel/softirq.c:649
  instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
  sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1043
 </IRQ>
 <TASK>

Fixes: 9872bec773c2 ("[NETFILTER]: nfnetlink: use RCU for queue instances hash")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/netfilter/nfnetlink_queue.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index 00f4bd21c59b419e96794127693c21ccb05e45b0..f1c31757e4969e8f975c7a1ebbc3b96148ec9724 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -169,7 +169,9 @@ instance_destroy_rcu(struct rcu_head *head)
 	struct nfqnl_instance *inst = container_of(head, struct nfqnl_instance,
 						   rcu);
 
+	rcu_read_lock();
 	nfqnl_flush(inst, NULL, 0);
+	rcu_read_unlock();
 	kfree(inst);
 	module_put(THIS_MODULE);
 }
-- 
2.45.0.rc1.225.g2a3ae87e7f-goog


             reply	other threads:[~2024-05-15 13:23 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-15 13:23 Eric Dumazet [this message]
2024-05-15 13:27 ` [PATCH net] netfilter: nfnetlink_queue: acquire rcu_read_lock() in instance_destroy_rcu() Florian Westphal
2024-05-15 13:39   ` Eric Dumazet
2024-05-15 13:42     ` Eric Dumazet
2024-05-15 14:10     ` Florian Westphal

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