From: Jinliang Zheng Introduce a dedicated ordered workqueue, macsec_wq, which will be used by subsequent patches to defer SA crypto cleanup (crypto_free_aead and related teardown) out of softirq context. Using a dedicated workqueue instead of system_wq allows macsec_exit() to drain exactly the work items belonging to this module via destroy_workqueue(), without interfering with unrelated work items on system_wq or causing unexpected delays elsewhere. rcu_barrier() in macsec_exit() ensures all in-flight rcu_work callbacks have enqueued their work items before destroy_workqueue() drains and destroys the queue, making the two-step teardown correct and complete. The same sequence is kept in the error path of macsec_init() as a precaution, to mirror macsec_exit() and stay safe if work ever becomes queueable before this point in the future. While at it, rename the error labels in macsec_init() from the resource-named style (rtnl:, notifier:, wq:) to the err_xxx: style (err_rtnl:, err_notifier:, err_destroy_wq:) to align with the broader kernel convention. Signed-off-by: Jinliang Zheng --- drivers/net/macsec.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c index f6cad0746a02..35284ff7a17e 100644 --- a/drivers/net/macsec.c +++ b/drivers/net/macsec.c @@ -26,6 +26,8 @@ #include +static struct workqueue_struct *macsec_wq; + /* SecTAG length = macsec_eth_header without the optional SCI */ #define MACSEC_TAG_LEN 6 @@ -4450,25 +4452,35 @@ static int __init macsec_init(void) { int err; + macsec_wq = alloc_workqueue("macsec", WQ_UNBOUND, 0); + if (!macsec_wq) + return -ENOMEM; + pr_info("MACsec IEEE 802.1AE\n"); err = register_netdevice_notifier(&macsec_notifier); if (err) - return err; + goto err_destroy_wq; err = rtnl_link_register(&macsec_link_ops); if (err) - goto notifier; + goto err_notifier; err = genl_register_family(&macsec_fam); if (err) - goto rtnl; + goto err_rtnl; return 0; -rtnl: +err_rtnl: rtnl_link_unregister(&macsec_link_ops); -notifier: +err_notifier: unregister_netdevice_notifier(&macsec_notifier); +err_destroy_wq: + /* Precautionary, mirrors macsec_exit() to stay safe if work + * ever becomes queueable before this point in the future. + */ + rcu_barrier(); + destroy_workqueue(macsec_wq); return err; } @@ -4478,6 +4490,7 @@ static void __exit macsec_exit(void) rtnl_link_unregister(&macsec_link_ops); unregister_netdevice_notifier(&macsec_notifier); rcu_barrier(); + destroy_workqueue(macsec_wq); } module_init(macsec_init); -- 2.39.3 From: Jinliang Zheng crypto_free_aead() can internally invoke vunmap() (e.g. via dma_free_attrs() in hardware crypto drivers such as hisi_sec2). vunmap() must not be called from softirq context, but free_rxsa() is an RCU callback that runs in softirq, leading to a kernel crash: vunmap+0x4c/0x70 __iommu_dma_free+0xd0/0x138 dma_free_attrs+0xf4/0x100 sec_aead_exit+0x64/0xb8 [hisi_sec2] crypto_destroy_tfm+0x98/0x110 free_rxsa+0x28/0x50 [macsec] rcu_do_batch+0x184/0x460 rcu_core+0xf4/0x1f8 handle_softirqs+0x118/0x330 Use rcu_work to defer the cleanup to a workqueue. rcu_work dispatches the worker asynchronously after the RCU grace period, so no thread blocks waiting, and concurrent releases of multiple SAs naturally share the same grace period. Fixes: c09440f7dcb3 ("macsec: introduce IEEE 802.1AE driver") Signed-off-by: Jinliang Zheng Reviewed-by: Sabrina Dubroca --- drivers/net/macsec.c | 8 +++++--- include/net/macsec.h | 4 +++- 2 files changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c index 35284ff7a17e..1b0ff7fa5ec6 100644 --- a/drivers/net/macsec.c +++ b/drivers/net/macsec.c @@ -176,9 +176,10 @@ static void macsec_rxsc_put(struct macsec_rx_sc *sc) call_rcu(&sc->rcu_head, free_rx_sc_rcu); } -static void free_rxsa(struct rcu_head *head) +static void free_rxsa_work(struct work_struct *work) { - struct macsec_rx_sa *sa = container_of(head, struct macsec_rx_sa, rcu); + struct macsec_rx_sa *sa = + container_of(to_rcu_work(work), struct macsec_rx_sa, destroy_work); crypto_free_aead(sa->key.tfm); free_percpu(sa->stats); @@ -188,7 +189,7 @@ static void free_rxsa(struct rcu_head *head) static void macsec_rxsa_put(struct macsec_rx_sa *sa) { if (refcount_dec_and_test(&sa->refcnt)) - call_rcu(&sa->rcu, free_rxsa); + queue_rcu_work(macsec_wq, &sa->destroy_work); } static struct macsec_tx_sa *macsec_txsa_get(struct macsec_tx_sa __rcu *ptr) @@ -1409,6 +1410,7 @@ static int init_rx_sa(struct macsec_rx_sa *rx_sa, char *sak, int key_len, rx_sa->next_pn = 1; refcount_set(&rx_sa->refcnt, 1); spin_lock_init(&rx_sa->lock); + INIT_RCU_WORK(&rx_sa->destroy_work, free_rxsa_work); return 0; } diff --git a/include/net/macsec.h b/include/net/macsec.h index bc7de5b53e54..0980ef36fbf0 100644 --- a/include/net/macsec.h +++ b/include/net/macsec.h @@ -9,6 +9,7 @@ #include #include +#include #include #include @@ -123,6 +124,7 @@ struct macsec_dev_stats { * @key: key structure * @ssci: short secure channel identifier * @stats: per-SA stats + * @destroy_work: deferred work to free the SA in process context after RCU grace period */ struct macsec_rx_sa { struct macsec_key key; @@ -136,7 +138,7 @@ struct macsec_rx_sa { bool active; struct macsec_rx_sa_stats __percpu *stats; struct macsec_rx_sc *sc; - struct rcu_head rcu; + struct rcu_work destroy_work; }; struct pcpu_rx_sc_stats { -- 2.39.3 From: Jinliang Zheng free_txsa() is an RCU callback running in softirq context, but calls crypto_free_aead() which can invoke vunmap() internally on hardware crypto drivers (e.g. hisi_sec2), triggering a kernel crash. Use rcu_work to defer the cleanup to a workqueue, for the same reasons as the analogous fix to free_rxsa() in the previous patch. Fixes: c09440f7dcb3 ("macsec: introduce IEEE 802.1AE driver") Signed-off-by: Jinliang Zheng Reviewed-by: Sabrina Dubroca --- drivers/net/macsec.c | 8 +++++--- include/net/macsec.h | 3 ++- 2 files changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c index 1b0ff7fa5ec6..79df71ea9edb 100644 --- a/drivers/net/macsec.c +++ b/drivers/net/macsec.c @@ -205,9 +205,10 @@ static struct macsec_tx_sa *macsec_txsa_get(struct macsec_tx_sa __rcu *ptr) return sa; } -static void free_txsa(struct rcu_head *head) +static void free_txsa_work(struct work_struct *work) { - struct macsec_tx_sa *sa = container_of(head, struct macsec_tx_sa, rcu); + struct macsec_tx_sa *sa = + container_of(to_rcu_work(work), struct macsec_tx_sa, destroy_work); crypto_free_aead(sa->key.tfm); free_percpu(sa->stats); @@ -217,7 +218,7 @@ static void free_txsa(struct rcu_head *head) static void macsec_txsa_put(struct macsec_tx_sa *sa) { if (refcount_dec_and_test(&sa->refcnt)) - call_rcu(&sa->rcu, free_txsa); + queue_rcu_work(macsec_wq, &sa->destroy_work); } static struct macsec_cb *macsec_skb_cb(struct sk_buff *skb) @@ -1510,6 +1511,7 @@ static int init_tx_sa(struct macsec_tx_sa *tx_sa, char *sak, int key_len, tx_sa->active = false; refcount_set(&tx_sa->refcnt, 1); spin_lock_init(&tx_sa->lock); + INIT_RCU_WORK(&tx_sa->destroy_work, free_txsa_work); return 0; } diff --git a/include/net/macsec.h b/include/net/macsec.h index 0980ef36fbf0..d962093ee923 100644 --- a/include/net/macsec.h +++ b/include/net/macsec.h @@ -176,6 +176,7 @@ struct macsec_rx_sc { * @key: key structure * @ssci: short secure channel identifier * @stats: per-SA stats + * @destroy_work: deferred work to free the SA in process context after RCU grace period */ struct macsec_tx_sa { struct macsec_key key; @@ -188,7 +189,7 @@ struct macsec_tx_sa { refcount_t refcnt; bool active; struct macsec_tx_sa_stats __percpu *stats; - struct rcu_head rcu; + struct rcu_work destroy_work; }; /** -- 2.39.3