Re: [PATCH net v2 1/2] net: ethernet: oa_tc6: Protect skb pointer used by two different kernel instances

[Jakub Kicinski]

On Tue, 30 Jun 2026 04:16:24 +0000 Selvamani Rajagopal wrote:
> > On Fri, 26 Jun 2026 08:35:18 -0700 Selvamani Rajagopal via B4 Relay
> > wrote:  
> > > Threaded IRQ uses waiting_tx_skb. Transmit path also uses
> > > this pointer without any mutual exclusion protection. As a
> > > result, it might leak skb buffer, particularly threaded IRQ
> > > runs in the middle of tranmsmit path, near skb_linearize.  
> > 
> > Can you say more ? only xmit sets waiting_tx_skb, the IRQ
> > clears it. So why is IRQ racing with xmit leading to drops?  
> 
> I believe xmit path and IRQ thread would run in different kernel
> instances. Imagine oa_tc6_try_spi_transfer call fails in threaded
> IRQ. It would set disable_irq. If xmit function didn't see that when
> it checked, but it is set before placing skb buffer in the
> waiting_tx_skb pointer (due to skb_linearize for example), the skb
> would be stuck in waiting_tx_skb.

Perhaps, but wouldn't that cause a stall not a leak?

Please do your digging and submit high quality patches which don't
require research. We get 150 patches a day in netdev, and all
maintainers have day jobs (contrary to popular belief)