Re: [PATCH net v3 v3 2/3] macsec: use rcu_work to defer RX SA crypto cleanup out of softirq

[Sabrina Dubroca]

2026-05-09, 11:33:46 +0800, alexjlzheng@xxxxxxxxx wrote:
> From: Jinliang Zheng <alexjlzheng@xxxxxxxxxxx>
> 
> 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 <alexjlzheng@xxxxxxxxxxx>
> ---
>  drivers/net/macsec.c | 8 +++++---
>  include/net/macsec.h | 4 +++-
>  2 files changed, 8 insertions(+), 4 deletions(-)

Reviewed-by: Sabrina Dubroca <sd@xxxxxxxxxxxxxxx>

-- 
Sabrina