CVE-2025-40090 in Linux
Sumário
de VulDB • 11/06/2026
No kernel do Linux, a seguinte vulnerabilidade foi corrigida:
ksmbd: corrige bloqueio recursivo no acesso à lista de handles RPC
Desde o commit 305853cce3794 ("ksmbd: Corrige condição de corrida no acesso à lista de handles RPC"), ksmbd_session_rpc_method() tenta travar sess->rpc_lock.
Isso causa conexões/tarefas pendentes (hung) quando um cliente tenta abrir uma named pipe. Usando a ferramenta rpcclient do Samba:
$ rpcclient //192.168.1.254 -U user%password $ rpcclient $> srvinfo <conexão fica pendente aqui>
Lado do kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" desativa esta mensagem. task:kworker/0:0 state:D stack:0 pid:5021 tgid:5021 ppid:2 flags:0x00200000 Workqueue: ksmbd-io handle_ksmbd_work Call trace: __schedule from schedule+0x3c/0x58 schedule from schedule_preempt_disabled+0xc/0x10 schedule_preempt_disabled from rwsem_down_read_slowpath+0x1b0/0x1d8 rwsem_down_read_slowpath from down_read+0x28/0x30 down_read from ksmbd_session_rpc_method+0x18/0x3c ksmbd_session_rpc_method from ksmbd_rpc_open+0x34/0x68 ksmbd_rpc_open from ksmbd_session_rpc_open+0x194/0x228 ksmbd_session_rpc_open from create_smb2_pipe+0x8c/0x2c8 create_smb2_pipe from smb2_open+0x10c/0x27ac smb2_open from handle_ksmbd_work+0x238/0x3dc handle_ksmbd_work from process_scheduled_works+0x160/0x25c process_scheduled_works from worker_thread+0x16c/0x1e8 worker_thread from kthread+0xa8/0xb8 kthread from ret_from_fork+0x14/0x38 Exception stack(0x8529ffb0 to 0x8529fff8)
A tarefa entra em deadlock porque o lock já está sendo segurado: ksmbd_session_rpc_open down_write(&sess->rpc_lock) ksmbd_rpc_open ksmbd_session_rpc_method down_read(&sess->rpc_lock) <-- deadlock
Ajusta os chamadores de ksmbd_session_rpc_method() para adquirir o lock quando necessário.
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