From: Tariq Toukan tariqt@nvidia.com
[ Upstream commit f08d8c1bb97c48f24a82afaa2fd8c140f8d3da8b ]
Socket destruction flow and tls_device_down function sync against each other using tls_device_lock and the context refcount, to guarantee the device resources are freed via tls_dev_del() by the end of tls_device_down.
In the following unfortunate flow, this won't happen: - refcount is decreased to zero in tls_device_sk_destruct. - tls_device_down starts, skips the context as refcount is zero, going all the way until it flushes the gc work, and returns without freeing the device resources. - only then, tls_device_queue_ctx_destruction is called, queues the gc work and frees the context's device resources.
Solve it by decreasing the refcount in the socket's destruction flow under the tls_device_lock, for perfect synchronization. This does not slow down the common likely destructor flow, in which both the refcount is decreased and the spinlock is acquired, anyway.
Fixes: e8f69799810c ("net/tls: Add generic NIC offload infrastructure") Reviewed-by: Maxim Mikityanskiy maximmi@nvidia.com Signed-off-by: Tariq Toukan tariqt@nvidia.com Reviewed-by: Jakub Kicinski kuba@kernel.org Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/tls/tls_device.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/net/tls/tls_device.c b/net/tls/tls_device.c index 6ae2ce411b4b..23eab7ac43ee 100644 --- a/net/tls/tls_device.c +++ b/net/tls/tls_device.c @@ -97,13 +97,16 @@ static void tls_device_queue_ctx_destruction(struct tls_context *ctx) unsigned long flags;
spin_lock_irqsave(&tls_device_lock, flags); + if (unlikely(!refcount_dec_and_test(&ctx->refcount))) + goto unlock; + list_move_tail(&ctx->list, &tls_device_gc_list);
/* schedule_work inside the spinlock * to make sure tls_device_down waits for that work. */ schedule_work(&tls_device_gc_work); - +unlock: spin_unlock_irqrestore(&tls_device_lock, flags); }
@@ -194,8 +197,7 @@ void tls_device_sk_destruct(struct sock *sk) clean_acked_data_disable(inet_csk(sk)); }
- if (refcount_dec_and_test(&tls_ctx->refcount)) - tls_device_queue_ctx_destruction(tls_ctx); + tls_device_queue_ctx_destruction(tls_ctx); } EXPORT_SYMBOL_GPL(tls_device_sk_destruct);