Re: [Intel-wired-lan] [PATCH iwl-net v2] ice: fix memleak in ice_init_tx_topology()

[Przemek Kitszel <przemyslaw.kitszel@intel.com>]

On 9/10/24 23:30, Jacob Keller wrote:
> 
> 
> On 9/10/2024 6:57 AM, Przemek Kitszel wrote:
>> Fix leak of the FW blob (DDP pkg).
>>
>> Make ice_cfg_tx_topo() const-correct, so ice_init_tx_topology() can avoid
>> copying whole FW blob. Copy just the topology section, and only when
>> needed. Reuse the buffer allocated for the read of the current topology.
>>
>> This was found by kmemleak, with the following trace for each PF:
>>      [<ffffffff8761044d>] kmemdup_noprof+0x1d/0x50
>>      [<ffffffffc0a0a480>] ice_init_ddp_config+0x100/0x220 [ice]
>>      [<ffffffffc0a0da7f>] ice_init_dev+0x6f/0x200 [ice]
>>      [<ffffffffc0a0dc49>] ice_init+0x29/0x560 [ice]
>>      [<ffffffffc0a10c1d>] ice_probe+0x21d/0x310 [ice]
>>
>> Constify ice_cfg_tx_topo() @buf parameter.
>> This cascades further down to few more functions.
>>
> 
> Nice!
> 
> Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>

Thanks!

> 
>> Fixes: cc5776fe1832 ("ice: Enable switching default Tx scheduler topology")
>> CC: Larysa Zaremba <larysa.zaremba@intel.com>
>> CC: Jacob Keller <jacob.e.keller@intel.com>
>> CC: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com>
>> CC: Mateusz Polchlopek <mateusz.polchlopek@intel.com>
>> Signed-off-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
>> ---
>> this patch obsoletes two other, so I'm dropping RB tags
>> v1, iwl-net: https://lore.kernel.org/netdev/20240904123306.14629-2-przemyslaw.kitszel@intel.com/
>>      wrong assumption that ice_get_set_tx_topo() does not modify the buffer
>>      on adminq SET variant, it sometimes does, to fill the response, thanks
>>      to Pucha Himasekhar Reddy for finding it out;
>> almost-const-correct iwl-next patch:
>> https://lore.kernel.org/intel-wired-lan/20240904093135.8795-2-przemyslaw.kitszel@intel.com
>> it was just some of this patch, now it is const-correct
>> ---
> 
> Right. So now we're doing the const correctness in this patch along with
> the fix?

yes

> 
> Would it make sense to fix the copy issue but leave const updates to the
> next tree?
> 
> I think I'm fine with this, but wonder if it will make backporting a bit
> more difficult? Probably not, given that this code is rarely modified.

hard to say, but I think one commit will make it a little bit easier, as
there will be smaller number of possible sets of commits applied
(at least in this case)

> 
> The const fixes are also relatively smaller than I anticipated :D

just adding kfree(), knowing the proper solution is to make code
const-correct, is just a workaround, not a proper fix

change is still rather small, and splitting into two would require
postponing -next one to be after -net (as it will just remove the added
kfree())

> 
> Thanks,
> Jake