[PATCH net] sfc: handle rhashtable walk errors in mport lookup

[Sang-Hoon Choi <csh0052@gmail.com>]

rhashtable_walk_next() can return ERR_PTR(-EAGAIN) when the table is
resized. efx_mae_lookup_mport() currently dereferences that value as an
mport descriptor.

Skip error values and continue the walk, as the other rhashtable walkers
in this driver already do.

Fixes: 5227adff37af ("sfc: add mport lookup based on driver's mport data")
Reported-by: Changyul Lee <lcy8047@gmail.com>
Assisted-by: LLM
Signed-off-by: Sang-Hoon Choi <csh0052@gmail.com>
---
Compile-tested the affected object with x86_64 allmodconfig
and W=1 (GCC 13.3.0). Base: mainline 3b7cab693ba2bab63774bf5b988e8a61b2ef0f32.
No hardware testing or runtime failure reproduction was performed.

 drivers/net/ethernet/sfc/mae.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/sfc/mae.c b/drivers/net/ethernet/sfc/mae.c
index 7a8606efd492..b6de61062a86 100644
--- a/drivers/net/ethernet/sfc/mae.c
+++ b/drivers/net/ethernet/sfc/mae.c
@@ -1030,6 +1030,8 @@ int efx_mae_lookup_mport(struct efx_nic *efx, u32 vf_idx, u32 *id)
 	rhashtable_walk_enter(&mae->mports_ht, &walk);
 	rhashtable_walk_start(&walk);
 	while ((m = rhashtable_walk_next(&walk)) != NULL) {
+		if (IS_ERR(m))
+			continue;
 		if (m->mport_type == MAE_MPORT_DESC_MPORT_TYPE_VNIC &&
 		    m->interface_idx == nic_data->local_mae_intf &&
 		    m->pf_idx == 0 &&