Re: [Intel-wired-lan] [PATCH iwl-net] ice: Fix increasing MSI-X on VF

[Simon Horman <horms@kernel.org>]

On Fri, Sep 27, 2024 at 05:15:40PM +0200, Marcin Szycik wrote:
> Increasing MSI-X value on a VF leads to invalid memory operations. This
> is caused by not reallocating some arrays.
> 
> Reproducer:
>   modprobe ice
>   echo 0 > /sys/bus/pci/devices/$PF_PCI/sriov_drivers_autoprobe
>   echo 1 > /sys/bus/pci/devices/$PF_PCI/sriov_numvfs
>   echo 17 > /sys/bus/pci/devices/$VF0_PCI/sriov_vf_msix_count
> 
> Default MSI-X is 16, so 17 and above triggers this issue.
> 
> KASAN reports:
> 
>   BUG: KASAN: slab-out-of-bounds in ice_vsi_alloc_ring_stats+0x38d/0x4b0 [ice]
>   Read of size 8 at addr ffff8888b937d180 by task bash/28433
>   (...)
> 
>   Call Trace:
>    (...)
>    ? ice_vsi_alloc_ring_stats+0x38d/0x4b0 [ice]
>    kasan_report+0xed/0x120
>    ? ice_vsi_alloc_ring_stats+0x38d/0x4b0 [ice]
>    ice_vsi_alloc_ring_stats+0x38d/0x4b0 [ice]
>    ice_vsi_cfg_def+0x3360/0x4770 [ice]
>    ? mutex_unlock+0x83/0xd0
>    ? __pfx_ice_vsi_cfg_def+0x10/0x10 [ice]
>    ? __pfx_ice_remove_vsi_lkup_fltr+0x10/0x10 [ice]
>    ice_vsi_cfg+0x7f/0x3b0 [ice]
>    ice_vf_reconfig_vsi+0x114/0x210 [ice]
>    ice_sriov_set_msix_vec_count+0x3d0/0x960 [ice]
>    sriov_vf_msix_count_store+0x21c/0x300
>    (...)
> 
>   Allocated by task 28201:
>    (...)
>    ice_vsi_cfg_def+0x1c8e/0x4770 [ice]
>    ice_vsi_cfg+0x7f/0x3b0 [ice]
>    ice_vsi_setup+0x179/0xa30 [ice]
>    ice_sriov_configure+0xcaa/0x1520 [ice]
>    sriov_numvfs_store+0x212/0x390
>    (...)
> 
> To fix it, use ice_vsi_rebuild() instead of ice_vf_reconfig_vsi(). This
> causes the required arrays to be reallocated taking the new queue count
> into account (ice_vsi_realloc_stat_arrays()). Set req_txq and req_rxq
> before ice_vsi_rebuild(), so that realloc uses the newly set queue
> count.
> 
> Additionally, ice_vsi_rebuild() does not remove VSI filters
> (ice_fltr_remove_all()), so ice_vf_init_host_cfg() is no longer
> necessary.
> 
> Reported-by: Jacob Keller <jacob.e.keller@intel.com>
> Fixes: 2a2cb4c6c181 ("ice: replace ice_vf_recreate_vsi() with ice_vf_reconfig_vsi()")
> Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
> Signed-off-by: Marcin Szycik <marcin.szycik@linux.intel.com>

Reviewed-by: Simon Horman <horms@kernel.org>