Re: [PATCH] net: nvidia: forcedeth: Fix two possible concurrency use-after-free bugs

[Jia-Ju Bai]

On 2019/1/8 20:54, Zhu Yanjun wrote:
> å 2019/1/8 20:45, Jia-Ju Bai åé:
> > In drivers/net/ethernet/nvidia/forcedeth.c, the functions
> > nv_start_xmit() and nv_start_xmit_optimized() can be concurrently
> > executed with nv_poll_controller().
> >
> > nv_start_xmit
> >    line 2321: prev_tx_ctx->skb = skb;
> >
> > nv_start_xmit_optimized
> >    line 2479: prev_tx_ctx->skb = skb;
> >
> > nv_poll_controller
> >    nv_do_nic_poll
> >      line 4134: spin_lock(&np->lock);
> >      nv_drain_rxtx
> >        nv_drain_tx
> >          nv_release_txskb
> >            line 2004: dev_kfree_skb_any(tx_skb->skb);
> >
> > Thus, two possible concurrency use-after-free bugs may occur.
> >
> > To fix these possible bugs,
>
>
> Does this really occur? Can you reproduce this ?

This bug is not found by the real execution.
It is found by a static tool written by myself, and then I check it by 
manual code review.


Best wishes,
Jia-Ju Bai