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SubjectRe: Re: [Intel-wired-lan] [PATCH] net: ixgbe: Fix memleak in ixgbe_configure_clsu32
> Dear Dinghao,
>
>
> Am 03.01.21 um 09:08 schrieb Dinghao Liu:
> > When ixgbe_fdir_write_perfect_filter_82599() fails,
> > input allocated by kzalloc() has not been freed,
> > which leads to memleak.
>
> Nice find. Thank you for your patches. Out of curiosity, do you use an
> analysis tool to find these issues?
>

Yes, these bugs are suggested by my static analysis tool.

> > Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
> > ---
> > drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 6 ++++--
> > 1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> > index 393d1c2cd853..e9c2d28efc81 100644
> > --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> > +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> > @@ -9582,8 +9582,10 @@ static int ixgbe_configure_clsu32(struct ixgbe_adapter *adapter,
> > ixgbe_atr_compute_perfect_hash_82599(&input->filter, mask);
> > err = ixgbe_fdir_write_perfect_filter_82599(hw, &input->filter,
> > input->sw_idx, queue);
> > - if (!err)
> > - ixgbe_update_ethtool_fdir_entry(adapter, input, input->sw_idx);
> > + if (err)
> > + goto err_out_w_lock;
> > +
> > + ixgbe_update_ethtool_fdir_entry(adapter, input, input->sw_idx);
> > spin_unlock(&adapter->fdir_perfect_lock);
> >
> > if ((uhtid != 0x800) && (adapter->jump_tables[uhtid]))
>
> Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
>
> I wonder, in the non-error case, how `input` and `jump` are freed.
>

I'm not sure if kfree(jump) will introduce bug. jump is allocated in a for
loop and has been passed to adapter->jump_tables. input and mask have new
definitions (kzalloc) after this loop, it's reasonable to free them on failure.
But jump is different. Maybe we should not free jump after the loop?

> Old code:
>
> > if (!err)
> > ixgbe_update_ethtool_fdir_entry(adapter, input, input->sw_idx);
> > spin_unlock(&adapter->fdir_perfect_lock);
> >
> > if ((uhtid != 0x800) && (adapter->jump_tables[uhtid]))
> > set_bit(loc - 1, (adapter->jump_tables[uhtid])->child_loc_map);
> >
> > kfree(mask);
> > return err;
>
> Should these two lines be replaced with `goto err_out`? (Though the name
> is confusing then, as it’s the non-error case.)
>

This also makes me confused. It seems that the check against untied is not error
handling code, but there is a kfree(mask) after it. Freeing allocated data on
success is not reasonable.

Regards,
Dinghao

> > err_out_w_lock:
> > spin_unlock(&adapter->fdir_perfect_lock);
> > err_out:
> > kfree(mask);
> > free_input:
> > kfree(input);
> > free_jump:
> > kfree(jump);
> > return err;
> > }
>
> Kind regards,
>
> Paul
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