Re: [PATCH net] net/mlx5: Use unique names for software steering caches

[Tariq Toukan <tariqt@nvidia.com>]

On 15/07/2026 11:22, Leon Romanovsky wrote:
> From: Leon Romanovsky <leonro@nvidia.com>
> 
> Each software steering domain creates its own slab caches, but all
> domains use the same names. When domains for two devices are alive at
> once, the second kmem_cache_create() triggers the following splat:
> 
> WARNING: mm/slab_common.c:111 at __kmem_cache_create_args+0xca/0x480, CPU#18: devlink/331372
> Modules linked in: act_mirred act_skbedit cls_matchall act_gact cls_flower sch_ingress
> vhost_vdpa veth nfnetlink_cttimeout openvswitch macvtap macvlan vfio_ap kvm nf_nat_tftp
> nf_conntrack_tftp nsh nf_conncount vfio_pci_core irqbypass scsi_debug vhost_net tap tun
> vhost_vsock vmw_vsock_virtio_transport_common vsock vhost nft_masq nft_reject_ipv4 act_csum
> cls_u32 sch_htb smc_diag smc ppp_deflate bsd_comp ppp_async crc_ccitt ppp_generic slhc loop
> algif_hash af_alg nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4
> nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4
> nf_tables mlx5_vdpa vdpa mlx5_ib dm_service_time ib_uverbs_support vringh ib_core vhost_iotlb
> mlx5_core s390_trng eadm_sch vfio_ccw mdev vfio_iommu_type1 vfio sch_fq_codel drm i2c_core
> dm_multipath drm_panel_orientation_quirks uvdevice diag288_wdt watchdog hmac_s390 prng aes_s390
> zfcp scsi_transport_fc pkey_pckmo pkey_cca pkey_ep11 zcrypt paes_s390 phmac_s390 rng_core
> scsi_dh_alua pkey scsi_dh_rdac scsi_dh_emc crypto_engine autofs4 ecdsa_generic ecc sha512 [last unloaded: openvswitch]
> CPU: 18 UID: 0 PID: 331372 Comm: devlink Tainted: G        W           7.2.0-20260712.rc2.git0.e3321fa3034d.300.fc44.s390x+debug #1 PREEMPT
> Tainted: [W]=WARN
> Hardware name: IBM 9175 ME1 701 (LPAR)
> Krnl PSW : 0704c00180000000 0000038139a6771a (__kmem_cache_create_args+0xda/0x480)
>              R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 RI:0 EA:3
> Krnl GPRS: 0000000000000000 0000000000000000 000003813b7de578 00000380b9eb8974
>              00000276c417f690 00000380b9eb8974 0000030144623348 00000277234a1660
>              0000000000000020 00000380b9eb8974 00000277234a1600 000003813b686d30
>              0000000000000000 00000380b9e9a810 0000038139a6771a 0000030144623238
> Krnl Code: 0000038139a6770a: c02000ebb737       larl    %r2,000003813b7de578
>              0000038139a67710: b9040039           lgr     %r3,%r9
>             *0000038139a67714: c0e5006e2eb2       brasl   %r14,000003813a82d478
>             >0000038139a6771a: a7390020           lghi    %r3,32
>              0000038139a6771e: b9040029           lgr     %r2,%r9
>              0000038139a67722: c0e5006cf98f       brasl   %r14,000003813a806a40
>              0000038139a67728: ec26018e007c       cgij    %r2,0,6,0000038139a67a44
>              0000038139a6772e: 58d0f0a4           l       %r13,164(%r15)
> Call Trace:
>    [<0000038139a6771a>] __kmem_cache_create_args+0xda/0x480
> ([<0000038139a676a2>] __kmem_cache_create_args+0x62/0x480)
>    [<00000380b9da1c70>] dr_domain_init_mem_resources+0x80/0x240 [mlx5_core]
>    [<00000380b9da226e>] dr_domain_init_resources.constprop.0+0x7e/0x2c0 [mlx5_core]
>    [<00000380b9da28b2>] mlx5dr_domain_create+0x132/0x250 [mlx5_core]
>    [<00000380b9dc1e20>] mlx5_cmd_dr_create_ns+0x30/0x90 [mlx5_core]
>    [<00000380b9cd8dbe>] mlx5_flow_namespace_set_mode+0x6e/0x130 [mlx5_core]
>    [<00000380b9d846ec>] esw_create_offloads_fdb_tables+0xac/0x5a0 [mlx5_core]
>    [<00000380b9d865b6>] esw_offloads_steering_init+0x1c6/0x480 [mlx5_core]
>    [<00000380b9d86e8e>] esw_offloads_enable+0x13e/0x410 [mlx5_core]
>    [<00000380b9d7b04a>] mlx5_eswitch_enable_locked+0x36a/0x540 [mlx5_core]
>    [<00000380b9d84ff0>] esw_offloads_start+0x50/0x1d0 [mlx5_core]
>    [<00000380b9d8774a>] mlx5_devlink_eswitch_mode_set+0x35a/0x3f0 [mlx5_core]
>    [<000003813a791e68>] devlink_nl_eswitch_set_doit+0x88/0x120
>    [<000003813a5b93ea>] genl_family_rcv_msg_doit+0xea/0x150
>    [<000003813a5b95c2>] genl_family_rcv_msg+0x172/0x210
>    [<000003813a5b96c2>] genl_rcv_msg+0x62/0xc0
>    [<000003813a5b7cac>] netlink_rcv_skb+0x5c/0x120
>    [<000003813a5b8f0c>] genl_rcv+0x3c/0x50
>    [<000003813a5b74a4>] netlink_unicast+0x1f4/0x2b0
>    [<000003813a5b783c>] netlink_sendmsg+0x2dc/0x460
>    [<000003813a4c9764>] __sock_sendmsg+0x64/0xd0
>    [<000003813a4cc878>] __sys_sendto+0x108/0x160
>    [<000003813a4cdf50>] __do_sys_socketcall+0x350/0x460
>    [<000003813a8184d2>] __do_syscall+0x172/0x750
>    [<000003813a82d5d2>] system_call+0x72/0x90
> 
> Prefix each cache name with the device name to make it unique.
> 
> Fixes: fd785e5213f0 ("net/mlx5: DR, Allocate icm_chunks from their own slab allocator")
> Fixes: fb628b71fb2a ("net/mlx5: DR, Allocate htbl from its own slab allocator")
> Reported-by: Christian Borntraeger <borntraeger@linux.ibm.com>
> Closes: https://lore.kernel.org/all/a3cea501-4d1f-47d5-b6d0-fcda9a0aab16@linux.ibm.com/
> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> ---
>   drivers/net/ethernet/mellanox/mlx5/core/steering/sws/dr_domain.c | 9 +++++++--
>   1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/steering/sws/dr_domain.c b/drivers/net/ethernet/mellanox/mlx5/core/steering/sws/dr_domain.c
> index fedefb565a21..c9f20a9033eb 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/steering/sws/dr_domain.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/sws/dr_domain.c
> @@ -98,9 +98,12 @@ int mlx5dr_domain_get_recalc_cs_ft_addr(struct mlx5dr_domain *dmn,
>   
>   static int dr_domain_init_mem_resources(struct mlx5dr_domain *dmn)
>   {
> +	char name[80];
>   	int ret;
>   
> -	dmn->chunks_kmem_cache = kmem_cache_create("mlx5_dr_chunks",
> +	snprintf(name, sizeof(name), "%s-mlx5_dr_chunks",
> +		 dev_name(dmn->mdev->device));
> +	dmn->chunks_kmem_cache = kmem_cache_create(name,
>   						   sizeof(struct mlx5dr_icm_chunk), 0,
>   						   SLAB_HWCACHE_ALIGN, NULL);
>   	if (!dmn->chunks_kmem_cache) {
> @@ -108,7 +111,9 @@ static int dr_domain_init_mem_resources(struct mlx5dr_domain *dmn)
>   		return -ENOMEM;
>   	}
>   
> -	dmn->htbls_kmem_cache = kmem_cache_create("mlx5_dr_htbls",
> +	snprintf(name, sizeof(name), "%s-mlx5_dr_htbls",
> +		 dev_name(dmn->mdev->device));
> +	dmn->htbls_kmem_cache = kmem_cache_create(name,
>   						  sizeof(struct mlx5dr_ste_htbl), 0,
>   						  SLAB_HWCACHE_ALIGN, NULL);
>   	if (!dmn->htbls_kmem_cache) {
> 
> ---
> base-commit: f8d04b0c74e989c515e0fa17bf779b730077f63e
> change-id: 20260715-kmem-dupliate-name-b151167f5119
> 
> Best regards,
> --
> Leon Romanovsky <leonro@nvidia.com>
> 
> 

Acked-by: Tariq Toukan <tariqt@nvidia.com>