[Intel-wired-lan] [PATCH net v2] ice: fix invalid check for empty list in ice_sched_assoc_vsi_to_agg()

[Arland, ArpanaX]

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces at osuosl.org> On Behalf Of Jakob Koschel
> Sent: Monday, March 20, 2023 6:18 PM
> To: Brandeburg, Jesse <jesse.brandeburg at intel.com>; Nguyen, Anthony L <anthony.l.nguyen at intel.com>; David S. Miller <davem at davemloft.net>; Eric Dumazet <edumazet at google.com>; Jakub Kicinski <kuba at kernel.org>; Paolo Abeni <pabeni at redhat.com>
> Cc: netdev at vger.kernel.org; Pietro Borrello <borrello at diag.uniroma1.it>; linux-kernel at vger.kernel.org; Bos, H.J. <h.j.bos at vu.nl>; Cristiano Giuffrida <c.giuffrida at vu.nl>; intel-wired-lan at lists.osuosl.org; Jakob Koschel <jkl820.git at gmail.com>
> Subject: [Intel-wired-lan] [PATCH net v2] ice: fix invalid check for empty list in ice_sched_assoc_vsi_to_agg()
>
> 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 comparison after the loop is undefined behavior and should be omitted if possible [1].
>
> Fixes: 37c592062b16 ("ice: remove the VSI info from previous agg")
> 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>
> ---
> Changes in v2:
> - add Fixes tag
> - Link to v1: https://lore.kernel.org/r/20230301-ice-fix-invalid-iterator-found-check-v1-1-87c26deed999@gmail.com
> ---
>  drivers/net/ethernet/intel/ice/ice_sched.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
>

Tested-by: Arpana Arland <arpanax.arland at intel.com> (A Contingent worker at Intel)