On Mon 26 Oct 2020 at 08:04, Leon Romanovsky <l...@kernel.org> wrote:
> From: Leon Romanovsky <leo...@nvidia.com>
>
> The tcf_block_unbind() expects that the caller will take block->cb_lock
> before calling it, however the code took RTNL lock instead. This causes
> to the following kernel panic.
>
> WARNING: CPU: 1 PID: 13524 at net/sched/cls_api.c:1488
> tcf_block_unbind+0x2db/0x420
> Modules linked in: mlx5_ib mlx5_core mlxfw ptp pps_core act_mirred
> act_tunnel_key cls_flower vxlan ip6_udp_tunnel udp_tunnel dummy sch_ingress
> openvswitch nsh xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink
> xt_addrtype iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4
> br_netfilter rpcrdma rdma_ucm ib_iser libiscsi scsi_transport_iscsi ib_umad
> ib_ipoib rdma_cm iw_cm ib_cm ib_uverbs ib_core overlay [last unloaded: mlxfw]
> CPU: 1 PID: 13524 Comm: test-ecmp-add-v Tainted: G W 5.9.0+ #1
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS
> rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
> RIP: 0010:tcf_block_unbind+0x2db/0x420
> Code: ff 48 83 c4 40 5b 5d 41 5c 41 5d 41 5e 41 5f c3 49 8d bc 24 30 01 00
> 00 be ff ff ff ff e8 7d 7f 70 00 85 c0 0f 85 7b fd ff ff <0f> 0b e9 74 fd ff
> ff 48 c7 c7 dc 6a 24 84 e8 02 ec fe fe e9 55 fd
> RSP: 0018:ffff888117d17968 EFLAGS: 00010246
> RAX: 0000000000000000 RBX: ffff88812f713c00 RCX: 1ffffffff0848d5b
> RDX: 0000000000000001 RSI: ffff88814fbc8130 RDI: ffff888107f2b878
> RBP: 1ffff11022fa2f3f R08: 0000000000000000 R09: ffffffff84115a87
> R10: fffffbfff0822b50 R11: ffff888107f2b898 R12: ffff88814fbc8000
> R13: ffff88812f713c10 R14: ffff888117d17a38 R15: ffff88814fbc80c0
> FS: 00007f6593d36740(0000) GS:ffff8882a4f00000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00005607a00758f8 CR3: 0000000131aea006 CR4: 0000000000170ea0
> Call Trace:
> tc_block_indr_cleanup+0x3e0/0x5a0
> ? tcf_block_unbind+0x420/0x420
> ? __mutex_unlock_slowpath+0xe7/0x610
> flow_indr_dev_unregister+0x5e2/0x930
> ? mlx5e_restore_tunnel+0xdf0/0xdf0 [mlx5_core]
> ? mlx5e_restore_tunnel+0xdf0/0xdf0 [mlx5_core]
> ? flow_indr_block_cb_alloc+0x3c0/0x3c0
> ? mlx5_db_free+0x37c/0x4b0 [mlx5_core]
> mlx5e_cleanup_rep_tx+0x8b/0xc0 [mlx5_core]
> mlx5e_detach_netdev+0xe5/0x120 [mlx5_core]
> mlx5e_vport_rep_unload+0x155/0x260 [mlx5_core]
> esw_offloads_disable+0x227/0x2b0 [mlx5_core]
> mlx5_eswitch_disable_locked.cold+0x38e/0x699 [mlx5_core]
> mlx5_eswitch_disable+0x94/0xf0 [mlx5_core]
> mlx5_device_disable_sriov+0x183/0x1f0 [mlx5_core]
> mlx5_core_sriov_configure+0xfd/0x230 [mlx5_core]
> sriov_numvfs_store+0x261/0x2f0
> ? sriov_drivers_autoprobe_store+0x110/0x110
> ? sysfs_file_ops+0x170/0x170
> ? sysfs_file_ops+0x117/0x170
> ? sysfs_file_ops+0x170/0x170
> kernfs_fop_write+0x1ff/0x3f0
> ? rcu_read_lock_any_held+0x6e/0x90
> vfs_write+0x1f3/0x620
> ksys_write+0xf9/0x1d0
> ? __x64_sys_read+0xb0/0xb0
> ? lockdep_hardirqs_on_prepare+0x273/0x3f0
> ? syscall_enter_from_user_mode+0x1d/0x50
> do_syscall_64+0x2d/0x40
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
>
> <...>
>
> ---[ end trace bfdd028ada702879 ]---
>
> Fixes: 0fdcf78d5973 ("net: use flow_indr_dev_setup_offload()")
> Signed-off-by: Leon Romanovsky <leo...@nvidia.com>
> ---
> net/sched/cls_api.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
> index faeabff283a2..fca147386ad2 100644
> --- a/net/sched/cls_api.c
> +++ b/net/sched/cls_api.c
> @@ -655,10 +655,8 @@ static void tc_block_indr_cleanup(struct flow_block_cb
> *block_cb)
> down_write(&block->cb_lock);
> list_del(&block_cb->driver_list);
> list_move(&block_cb->list, &bo.cb_list);
> - up_write(&block->cb_lock);
> - rtnl_lock();
> tcf_block_unbind(block, &bo);
> - rtnl_unlock();
> + up_write(&block->cb_lock);
Hi Leon,
This fix probably breaks all other drivers besides mlx5 that require
rtnl lock on TC filter update path (called from tp->ops->reoffload()).
I suggest both rtnl lock and cb_lock are required here.
Regards,
Vlad
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