{"schema_version":"1.9.0","id":"CVE-2025-21809","published":"2025-02-27T20:01:00.969Z","modified":"2026-08-12T03:51:16.085937467Z","related":["USN-7521-2"],"summary":"rxrpc, afs: Fix peer hash locking vs RCU callback","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc, afs: Fix peer hash locking vs RCU callback\n\nIn its address list, afs now retains pointers to and refs on one or more\nrxrpc_peer objects.  The address list is freed under RCU and at this time,\nit puts the refs on those peers.\n\nNow, when an rxrpc_peer object runs out of refs, it gets removed from the\npeer hash table and, for that, rxrpc has to take a spinlock.  However, it\nis now being called from afs's RCU cleanup, which takes place in BH\ncontext - but it is just taking an ordinary spinlock.\n\nThe put may also be called from non-BH context, and so there exists the\npossibility of deadlock if the BH-based RCU cleanup happens whilst the hash\nspinlock is held.  This led to the attached lockdep complaint.\n\nFix this by changing spinlocks of rxnet->peer_hash_lock back to\nBH-disabling locks.\n\n    ================================\n    WARNING: inconsistent lock state\n    6.13.0-rc5-build2+ #1223 Tainted: G            E\n    --------------------------------\n    inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.\n    swapper/1/0 [HC0[0]:SC1[1]:HE1:SE0] takes:\n    ffff88810babe228 (&rxnet->peer_hash_lock){+.?.}-{3:3}, at: rxrpc_put_peer+0xcb/0x180\n    {SOFTIRQ-ON-W} state was registered at:\n      mark_usage+0x164/0x180\n      __lock_acquire+0x544/0x990\n      lock_acquire.part.0+0x103/0x280\n      _raw_spin_lock+0x2f/0x40\n      rxrpc_peer_keepalive_worker+0x144/0x440\n      process_one_work+0x486/0x7c0\n      process_scheduled_works+0x73/0x90\n      worker_thread+0x1c8/0x2a0\n      kthread+0x19b/0x1b0\n      ret_from_fork+0x24/0x40\n      ret_from_fork_asm+0x1a/0x30\n    irq event stamp: 972402\n    hardirqs last  enabled at (972402): [<ffffffff8244360e>] _raw_spin_unlock_irqrestore+0x2e/0x50\n    hardirqs last disabled at (972401): [<ffffffff82443328>] _raw_spin_lock_irqsave+0x18/0x60\n    softirqs last  enabled at (972300): [<ffffffff810ffbbe>] handle_softirqs+0x3ee/0x430\n    softirqs last disabled at (972313): [<ffffffff810ffc54>] __irq_exit_rcu+0x44/0x110\n\n    other info that might help us debug this:\n     Possible unsafe locking scenario:\n           CPU0\n           ----\n      lock(&rxnet->peer_hash_lock);\n      <Interrupt>\n        lock(&rxnet->peer_hash_lock);\n\n     *** DEADLOCK ***\n    1 lock held by swapper/1/0:\n     #0: ffffffff83576be0 (rcu_callback){....}-{0:0}, at: rcu_lock_acquire+0x7/0x30\n\n    stack backtrace:\n    CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G            E      6.13.0-rc5-build2+ #1223\n    Tainted: [E]=UNSIGNED_MODULE\n    Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014\n    Call Trace:\n     <IRQ>\n     dump_stack_lvl+0x57/0x80\n     print_usage_bug.part.0+0x227/0x240\n     valid_state+0x53/0x70\n     mark_lock_irq+0xa5/0x2f0\n     mark_lock+0xf7/0x170\n     mark_usage+0xe1/0x180\n     __lock_acquire+0x544/0x990\n     lock_acquire.part.0+0x103/0x280\n     _raw_spin_lock+0x2f/0x40\n     rxrpc_put_peer+0xcb/0x180\n     afs_free_addrlist+0x46/0x90 [kafs]\n     rcu_do_batch+0x2d2/0x640\n     rcu_core+0x2f7/0x350\n     handle_softirqs+0x1ee/0x430\n     __irq_exit_rcu+0x44/0x110\n     irq_exit_rcu+0xa/0x30\n     sysvec_apic_timer_interrupt+0x7f/0xa0\n     </IRQ>","affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"72904d7b9bfbf2dd146254edea93958bc35bbbfe"},{"fixed":"10ba5a3d57af20e494e0d979d1894260989235dd"},{"fixed":"0e77dd41689637ac4e1b8fe0f27541f373640855"},{"fixed":"79d458c13056559d49b5e41fbc4b6890e68cf65b"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"0"},{"last_affected":"056fc740be000d39a7dba700a935f3bbfbc664e6"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6.7.3"},{"fixed":"6.8"}]}],"versions":["v6.7-rc1","v6.7.2","v6.7.1","v6.7","v6.7-rc3","v6.7-rc8","v6.7-rc7","v6.7-rc6","v6.7-rc2","v6.7-rc4","v6.7-rc5","v6.6","v6.6-rc1","v6.6-rc5","v6.6-rc3","v6.6-rc7","v6.6-rc6","v6.6-rc4","v6.6-rc2","v6.5","v6.5-rc1","v6.5-rc2","v6.5-rc7","v6.5-rc4","v6.5-rc3","v6.5-rc6","v6.5-rc5","v6.4","v6.4-rc7","v6.4-rc1","v6.4-rc6","v6.4-rc5","v6.4-rc3","v6.4-rc4","v6.4-rc2","v6.3","v6.3-rc1","v6.3-rc7","v6.3-rc2","v6.3-rc3","v6.3-rc5","v6.3-rc6","v6.3-rc4","v6.2-rc6","v6.2-rc1","v6.2","v6.2-rc2","v6.2-rc8","v6.2-rc5","v6.2-rc4","v6.2-rc7","v6.2-rc3","v6.1-rc1","v6.1","v6.1-rc8","v6.1-rc3","v6.1-rc6","v6.1-rc7","v6.1-rc4","v6.1-rc2","v6.1-rc5","v6.0-rc1","v6.0","v6.0-rc7","v6.0-rc3","v6.0-rc2","v6.0-rc6","v6.0-rc4","v6.0-rc5","v5.19","v5.19-rc1","v5.19-rc5","v5.19-rc8","v5.19-rc6","v5.18","v5.19-rc2","v5.19-rc7","v5.19-rc3","v5.19-rc4","v5.18-rc1","v5.18-rc7","v5.18-rc2","v5.18-rc5","v5.17","v5.18-rc4","v5.18-rc3","v5.18-rc6","v5.17-rc6","v5.17-rc4","v5.17-rc8","v5.17-rc7","v5.17-rc1","v5.17-rc3","v5.17-rc2","v5.17-rc5","v5.16","v5.16-rc1","v5.16-rc8","v5.16-rc5","v5.16-rc6","v5.16-rc7","v5.16-rc3","v5.16-rc2","v5.16-rc4","v5.15","v5.15-rc2","v5.15-rc1","v5.15-rc4","v5.15-rc7","v5.15-rc3","v5.15-rc5","v5.15-rc6","v5.14","v5.14-rc3","v5.14-rc1","v5.14-rc2","v5.14-rc7","v5.14-rc6","v5.13-rc1","v5.14-rc5","v5.14-rc4","v5.13","v5.13-rc6","v5.13-rc7","v5.13-rc3","v5.13-rc2","v5.13-rc4","v5.13-rc5","v5.12","v5.12-rc2","v5.12-rc1-dontuse","v5.12-rc1","v5.12-rc8","v5.12-rc3","v5.12-rc7","v5.12-rc5","v5.12-rc6","v5.12-rc4","v5.10","v5.11","v5.11-rc3","v5.11-rc7","v5.11-rc6","v5.11-rc5","v5.11-rc1","v5.11-rc4","v5.11-rc2","v5.10-rc1","v5.10-rc7","v5.10-rc4","v5.10-rc3","v5.10-rc6","v5.9","v5.10-rc2","v5.10-rc5","v5.9-rc1","v5.9-rc7","v5.9-rc8","v5.9-rc6","v5.9-rc4","v5.9-rc5","v5.9-rc3","v5.9-rc2","v5.8","v5.7","v5.8-rc2","v5.8-rc1","v5.8-rc7","v5.8-rc5","v5.8-rc3","v5.8-rc4","v5.8-rc6","v5.7-rc4","v5.7-rc7","v5.7-rc1","v5.7-rc3","v5.7-rc2","v5.7-rc5","v5.7-rc6","v5.6","v5.6-rc1","v5.6-rc7","v5.6-rc6","v5.6-rc3","v5.6-rc4","v5.6-rc2","v5.6-rc5","v5.5","v5.5-rc5","v5.5-rc7","v5.5-rc2","v5.5-rc1","v5.4","v5.5-rc4","v5.5-rc3","v5.5-rc6","v5.4-rc1","v5.4-rc6","v5.4-rc3","v5.4-rc4","v5.4-rc8","v5.4-rc7","v5.4-rc5","v5.3","v5.4-rc2","v5.3-rc5","v5.3-rc1","v5.3-rc2","v5.3-rc3","v5.3-rc8","v5.3-rc7","v5.3-rc4","v5.2","v5.3-rc6","v5.2-rc2","v5.2-rc7","v5.2-rc4","v5.2-rc1","v5.2-rc5","v5.2-rc6","v5.2-rc3","v5.1","v5.0-rc8","v5.1-rc7","v5.1-rc1","v5.1-rc6","v5.1-rc5","v5.0","v5.1-rc3","v5.1-rc2","v5.1-rc4","v5.0-rc1","v5.0-rc4","v5.0-rc3","v5.0-rc6","v5.0-rc7","v5.0-rc2","v5.0-rc5","v4.20-rc1","v4.19","v4.20","v4.20-rc7","v4.20-rc5","v4.20-rc6","v4.20-rc4","v4.20-rc2","v4.20-rc3","v4.19-rc2","v4.19-rc8","v4.19-rc4","v4.19-rc1","v4.19-rc7","v4.19-rc6","v4.19-rc5","v4.19-rc3","v4.18","v4.18-rc1","v4.18-rc8","v4.18-rc2","v4.18-rc5","v4.18-rc6","v4.18-rc7","v4.17","v4.18-rc3","v4.18-rc4","v4.17-rc1","v4.17-rc2","v4.17-rc7","v4.17-rc3","v4.17-rc4","v4.16","v4.17-rc6","v4.17-rc5","v4.16-rc7","v4.16-rc4","v4.16-rc1","v4.16-rc2","v4.16-rc5","v4.16-rc3","v4.16-rc6","v4.14","v4.15","v4.15-rc1","v4.15-rc4","v4.15-rc9","v4.15-rc8","v4.15-rc7","v4.15-rc3","v4.15-rc2","v4.15-rc5","v4.15-rc6","v4.14-rc1","v4.14-rc7","v4.14-rc3","v4.13","v4.14-rc8","v4.14-rc4","v4.14-rc6","v4.14-rc2","v4.14-rc5","v4.13-rc2","v4.13-rc1","v4.13-rc3","v4.13-rc7","v4.13-rc4","v4.13-rc5","v4.13-rc6","v4.12-rc1","v4.12","v4.12-rc5","v4.12-rc7","v4.12-rc6","v4.12-rc4","v4.12-rc2","v4.12-rc3","v4.11","v4.11-rc1","v4.11-rc6","v4.11-rc8","v4.11-rc7","v4.11-rc3","v4.11-rc5","v4.11-rc2","v4.11-rc4","v4.10","v4.9","v4.10-rc8","v4.10-rc3","v4.10-rc1","v4.10-rc7","v4.10-rc6","v4.10-rc2","v4.10-rc5","v4.10-rc4","v4.9-rc7","v4.9-rc6","v4.9-rc8","v4.9-rc1","v4.9-rc5","v4.9-rc3","v4.9-rc4","v4.9-rc2","v4.8","v4.8-rc8","v4.8-rc2","v4.8-rc1","v4.8-rc7","v4.8-rc6","v4.8-rc5","v4.8-rc4","v4.8-rc3","v4.7","v4.7-rc4","v4.7-rc2","v4.7-rc1","v4.7-rc7","v4.7-rc6","v4.7-rc3","v4.7-rc5","v4.6","v4.6-rc1","v4.6-rc6","v4.6-rc4","v4.6-rc7","v4.6-rc5","v4.5-rc4","v4.6-rc2","v4.6-rc3","v4.5","v4.4","v4.5-rc1","v4.5-rc6","v4.5-rc2","v4.5-rc7","v4.5-rc5","v4.5-rc3","v4.4-rc1","v4.4-rc2","v4.4-rc8","v4.4-rc3","v4.4-rc7","v4.4-rc5","v4.4-rc6","v4.4-rc4","v4.3","v4.3-rc1","v4.3-rc6","v4.3-rc4","v4.3-rc2","v4.3-rc7","v4.3-rc5","v4.3-rc3","v4.2","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