CVE-2025-21809: In the Linux kernel, the following vulnerability has been resolved:  rxrpc, afs: Fix peer hash locking vs RCU callback  In its address list, afs now retains pointers to and refs on one or more rxrpc_peer objects.  The address list is freed under RCU and at this time, it puts the refs on those peers.  Now, when an rxrpc_peer object runs out of refs, it gets removed from the peer hash table and, for that, rxrpc has to take a spinlock.  However, it is now being called from afs's RCU cleanup, which takes place in BH context - but it is just taking an ordinary spinlock.  The put may also be called from non-BH context, and so there exists the possibility of deadlock if the BH-based RCU cleanup happens whilst the hash spinlock is held.  This led to the attached lockdep complaint.  Fix this by changing spinlocks of rxnet->peer_hash_lock back to BH-disabling locks.      ================================     WARNING: inconsistent lock state     6.13.0-rc5-build2+ #1223 Tainted: G            E     --------------------------------     inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.     swapper/1/0 [HC0[0]:SC1[1]:HE1:SE0] takes:     ffff88810babe228 (&rxnet->peer_hash_lock){+.?.}-{3:3}, at: rxrpc_put_peer+0xcb/0x180     {SOFTIRQ-ON-W} state was registered at:       mark_usage+0x164/0x180       __lock_acquire+0x544/0x990       lock_acquire.part.0+0x103/0x280       _raw_spin_lock+0x2f/0x40       rxrpc_peer_keepalive_worker+0x144/0x440       process_one_work+0x486/0x7c0       process_scheduled_works+0x73/0x90       worker_thread+0x1c8/0x2a0       kthread+0x19b/0x1b0       ret_from_fork+0x24/0x40       ret_from_fork_asm+0x1a/0x30     irq event stamp: 972402     hardirqs last  enabled at (972402): [<ffffffff8244360e>] _raw_spin_unlock_irqrestore+0x2e/0x50     hardirqs last disabled at (972401): [<ffffffff82443328>] _raw_spin_lock_irqsave+0x18/0x60     softirqs last  enabled at (972300): [<ffffffff810ffbbe>] handle_softirqs+0x3ee/0x430     softirqs last disabled at (972313): [<ffffffff810ffc54>] __irq_exit_rcu+0x44/0x110      other info that might help us debug this:      Possible unsafe locking scenario:            CPU0            ----       lock(&rxnet->peer_hash_lock);       <Interrupt>         lock(&rxnet->peer_hash_lock);       *** DEADLOCK ***     1 lock held by swapper/1/0:      #0: ffffffff83576be0 (rcu_callback){....}-{0:0}, at: rcu_lock_acquire+0x7/0x30      stack backtrace:     CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G            E      6.13.0-rc5-build2+ #1223     Tainted: [E]=UNSIGNED_MODULE     Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014     Call Trace:      <IRQ>      dump_stack_lvl+0x57/0x80      print_usage_bug.part.0+0x227/0x240      valid_state+0x53/0x70      mark_lock_irq+0xa5/0x2f0      mark_lock+0xf7/0x170      mark_usage+0xe1/0x180      __lock_acquire+0x544/0x990      lock_acquire.part.0+0x103/0x280      _raw_spin_lock+0x2f/0x40      rxrpc_put_peer+0xcb/0x180      afs_free_addrlist+0x46/0x90 [kafs]      rcu_do_batch+0x2d2/0x640      rcu_core+0x2f7/0x350      handle_softirqs+0x1ee/0x430      __irq_exit_rcu+0x44/0x110      irq_exit_rcu+0xa/0x30      sysvec_apic_timer_interrupt+0x7f/0xa0      </IRQ>