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 --- 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 52d6dd03ac92..67e4e3f439c7 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