Re: [PATCH v20 net-next 6/9] octeontx2: cn20k: Coordinate default rules with NIX LF lifecycle

[Ratheesh Kannoth]

On 2026-06-09 at 09:34:50, Ratheesh Kannoth (rkannoth@xxxxxxxxxxx) wrote:
> Add NIX_LF_DONT_FREE_DFT_IDXS so the PF can send NIX LF free during hw
> reinit or teardown without the AF freeing CN20K default NPC rule indexes
> while the driver still owns that state (otx2_init_hw_resources and
> otx2_free_hw_resources).
>
> On CN20K, allocate default NPC rules from NIX LF alloc before
> nix_interface_init, roll back with npc_cn20k_dft_rules_free on failure,
> and free from NIX LF free when the new flag is not set. Tighten
> rvu_mbox_handler_nix_lf_alloc error handling: use a single rc, propagate
> qmem_alloc and other errors, and set -ENOMEM only when kcalloc fails
> (remove the blanket -ENOMEM at the free_mem path).
>
> Signed-off-by: Ratheesh Kannoth <rkannoth@xxxxxxxxxxx>

https://sashiko.dev/#/patchset/20260609040453.711932-1-rkannoth%40marvell.com says:
>
>> -	if (err)
>> +	rc = qmem_alloc(rvu->dev, &pfvf->rq_ctx, req->rq_cnt, hwctx_size);
>> +	if (rc)
>>  		goto free_mem;
>>
>>  	pfvf->rq_bmap = kcalloc(req->rq_cnt, sizeof(long), GFP_KERNEL);
>> -	if (!pfvf->rq_bmap)
>> +	if (!pfvf->rq_bmap) {
>> +		rc = -ENOMEM;
>>  		goto free_mem;
>> +	}
>This is a pre-existing issue, but does this code allow a memory leak if a VF
>sends consecutive allocation requests?
>Looking at rvu_mbox_handler_nix_lf_alloc(), the AF driver handles the NIX LF
>allocation by allocating DMA memory via qmem_alloc() and heap memory via
>kcalloc(). It appears to directly overwrite the context pointers (such as
>pfvf->rq_ctx and pfvf->rq_bmap) without checking if they are already
>allocated.
>If a misbehaving VF sends this allocation message multiple times sequentially
>without an intervening NIX_LF_FREE message, could the previously allocated
>memory be silently overwritten and leaked?
>It looks like a similar pattern might also exist for NPA LF allocations in
>rvu_mbox_handler_npa_lf_alloc() where pfvf->aura_ctx and pfvf->pool_ctx are
>allocated in a similar manner.

This is a pre-existing issue, will post a patch to "net" tree post merge of this series.