[Intel-wired-lan] [PATCH net] ice: fix invalid check for empty list in ice_sched_assoc_vsi_to_agg()
Tony Nguyen
anthony.l.nguyen at intel.com
Tue Mar 14 18:50:58 UTC 2023
On 3/13/2023 9:31 AM, Jakob Koschel wrote:
> The code implicitly assumes that the list iterator finds a correct
> handle. If 'vsi_handle' is not found the 'old_agg_vsi_info' was
> pointing to an bogus memory location. For safety a separate list
> iterator variable should be used to make the != NULL check on
> 'old_agg_vsi_info' correct under any circumstances.
>
> Additionally Linus proposed to avoid any use of the list iterator
> variable after the loop, in the attempt to move the list iterator
> variable declaration into the macro to avoid any potential misuse after
> the loop. Using it in a pointer comparision after the loop is undefined
> behavior and should be omitted if possible [1].
>
> Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/ [1]
> Signed-off-by: Jakob Koschel <jkl820.git at gmail.com>
The patch looks fine, however, for net patches, could you please include
a Fixes: tag.
Thanks,
Tony
> ---
> drivers/net/ethernet/intel/ice/ice_sched.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/ice/ice_sched.c b/drivers/net/ethernet/intel/ice/ice_sched.c
> index 4eca8d195ef0..b7682de0ae05 100644
> --- a/drivers/net/ethernet/intel/ice/ice_sched.c
> +++ b/drivers/net/ethernet/intel/ice/ice_sched.c
> @@ -2788,7 +2788,7 @@ static int
> ice_sched_assoc_vsi_to_agg(struct ice_port_info *pi, u32 agg_id,
> u16 vsi_handle, unsigned long *tc_bitmap)
> {
> - struct ice_sched_agg_vsi_info *agg_vsi_info, *old_agg_vsi_info = NULL;
> + struct ice_sched_agg_vsi_info *agg_vsi_info, *iter, *old_agg_vsi_info = NULL;
> struct ice_sched_agg_info *agg_info, *old_agg_info;
> struct ice_hw *hw = pi->hw;
> int status = 0;
> @@ -2806,11 +2806,13 @@ ice_sched_assoc_vsi_to_agg(struct ice_port_info *pi, u32 agg_id,
> if (old_agg_info && old_agg_info != agg_info) {
> struct ice_sched_agg_vsi_info *vtmp;
>
> - list_for_each_entry_safe(old_agg_vsi_info, vtmp,
> + list_for_each_entry_safe(iter, vtmp,
> &old_agg_info->agg_vsi_list,
> list_entry)
> - if (old_agg_vsi_info->vsi_handle == vsi_handle)
> + if (iter->vsi_handle == vsi_handle) {
> + old_agg_vsi_info = iter;
> break;
> + }
> }
>
> /* check if entry already exist */
>
> ---
> base-commit: eeac8ede17557680855031c6f305ece2378af326
> change-id: 20230301-ice-fix-invalid-iterator-found-check-0a3e5b43dfb3
>
> Best regards,
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