Why ieee80211_mgd_probe_ap ignores MLD vifs?

Why ieee80211_mgd_probe_ap ignores MLD vifs?

[Ben Greear]

Hello,

In 6.7.0-rc1-ish, I see a splat from the WARN_ON_ONCE below.  I enabled MLO on some
be200 radios against a TPLINK AP, attempting to connect to the MLO ssid.

I traced git back to where code was originally added (in slightly different form),
but that was a big patch and it is not clear to me why we should not probe here.

So, can anyone share the reason?

static void ieee80211_mgd_probe_ap(struct ieee80211_sub_if_data *sdata,
				   bool beacon)
{
	struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
	bool already = false;

	lockdep_assert_wiphy(sdata->local->hw.wiphy);

	if (WARN_ON_ONCE(ieee80211_vif_is_mld(&sdata->vif)))
		return;

4442 Nov 09 09:58:05 ct523c-2103 kernel: ------------[ cut here ]------------
4443 Nov 09 09:58:05 ct523c-2103 kernel: WARNING: CPU: 0 PID: 961 at net/mac80211/mlme.c:3382 ieee80211_mgd_probe_ap+0x81/0xc0 [mac80211]
4444 Nov 09 09:58:05 ct523c-2103 kernel: Modules linked in: nf_conntrack_netlink nf_conntrack nfnetlink vrf nf_defrag_ipv6 nf_defrag_ipv4 bpfilter 8021q 
garp mrp stp llc macvlan pktgen rpcrdma rdma_cm iw_cm ib_cm ib_core qrtr f71882fg intel_rapl_msr iTCO_wdt ee1004 intel_pmc_bxt iTCO_vendor_support        iwlmvm 
coretemp intel_rapl_common intel_tcc_cooling mac80211 x86_pkg_temp_thermal snd_hda_codec_hdmi intel_powerclamp kvm_intel 
snd_hda_codec_realtek iwlwifi snd_hda_codec_generic kvm ledtrig_audio irqbypass cfg80211 snd_hda_intel snd_intel_dspcfg intel_wmi_thunderbolt pcspkr 
snd_hda_codec snd_hda_core snd_hwdep snd_seq tpm_crb bfq snd_seq_device mei_hdcp mei_pxp snd_pcm snd_timer i2c_i801 snd tpm_tis intel_pch_thermal 
soundcore i2c_smbus tpm_tis_core tpm acpi_pad nfsd auth_rpcgss nfs_acl lockd grace sch_fq_codel sunrpc fuse zram raid1 dm_raid raid456 libcrc32c 
async_raid6_recov async_memcpy async_pq async_xor xor async_tx raid6_pq igb i915 i2c_algo_bit drm_buddy intel_gtt drm_display_helper drm_kms_helper       cec 
rc_core ttm drm ixgbe agpgart mdio dca
4445 Nov 09 09:58:05 ct523c-2103 kernel:  xhci_pci mei_wdt xhci_pci_renesas hwmon i2c_core video wmi [last unloaded: nfnetlink]
4446 Nov 09 09:58:05 ct523c-2103 kernel: CPU: 0 PID: 961 Comm: kworker/u16:13 Tainted: G        W          6.7.0-rc1+ #6
4447 Nov 09 09:58:05 ct523c-2103 kernel: Hardware name: Default string Default string/SKYBAY, BIOS 5.12 02/21/2023
4448 Nov 09 09:58:05 ct523c-2103 kernel: Workqueue: events_unbound cfg80211_wiphy_work [cfg80211]
4449 Nov 09 09:58:05 ct523c-2103 kernel: RIP: 0010:ieee80211_mgd_probe_ap+0x81/0xc0 [mac80211]
4450 Nov 09 09:58:05 ct523c-2103 kernel: Code: 02 89 93 3c 14 00 00 a8 02 75 d1 48 8b bb 60 0f 00 00 e8 a2 fd ff ff 48 89 df c7 83 20 14 00 00 00 00 00 
00 5b e9 2f fb ff ff <0f> 0b c3 8b 0d ca d7 03 00 48 8d 97 78 0f 00 00 31 ff 48 c7 c6 30
4451 Nov 09 09:58:05 ct523c-2103 kernel: RSP: 0018:ffffc900035f3e40 EFLAGS: 00010202
4452 Nov 09 09:58:05 ct523c-2103 kernel: RAX: 0000000000000008 RBX: ffff888135a70378 RCX: ffff888135a70398
4453 Nov 09 09:58:05 ct523c-2103 kernel: RDX: ffff888135a70398 RSI: 0000000000000001 RDI: ffff888138e68a00
4454 Nov 09 09:58:05 ct523c-2103 kernel: RBP: ffff888138e69de0 R08: 745e72736d647564 R09: ffff88813870b200
4455 Nov 09 09:58:05 ct523c-2103 kernel: R10: 000000000000000f R11: fefefefefefefeff R12: ffff888135a703c0
4456 Nov 09 09:58:05 ct523c-2103 kernel: R13: ffff888135a703a8 R14: ffff888120073c05 R15: ffff888120058cb0
4457 Nov 09 09:58:05 ct523c-2103 kernel: FS:  0000000000000000(0000) GS:ffff88845dc00000(0000) knlGS:0000000000000000
4458 Nov 09 09:58:05 ct523c-2103 kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
4459 Nov 09 09:58:05 ct523c-2103 kernel: CR2: 00007fa4a864ccc8 CR3: 0000000002634005 CR4: 00000000003706f0
4460 Nov 09 09:58:05 ct523c-2103 kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
4461 Nov 09 09:58:05 ct523c-2103 kernel: DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
4462 Nov 09 09:58:05 ct523c-2103 kernel: Call Trace:
4463 Nov 09 09:58:05 ct523c-2103 kernel:  <TASK>
4464 Nov 09 09:58:05 ct523c-2103 kernel:  ? ieee80211_mgd_probe_ap+0x81/0xc0 [mac80211]
4465 Nov 09 09:58:05 ct523c-2103 kernel:  ? __warn+0x78/0x130
4466 Nov 09 09:58:05 ct523c-2103 kernel:  ? ieee80211_mgd_probe_ap+0x81/0xc0 [mac80211]
4467 Nov 09 09:58:05 ct523c-2103 kernel:  ? report_bug+0x169/0x1a0
4468 Nov 09 09:58:05 ct523c-2103 kernel:  ? handle_bug+0x41/0x70
4469 Nov 09 09:58:05 ct523c-2103 kernel:  ? exc_invalid_op+0x13/0x60
4470 Nov 09 09:58:05 ct523c-2103 kernel:  ? asm_exc_invalid_op+0x16/0x20
4471 Nov 09 09:58:05 ct523c-2103 kernel:  ? ieee80211_mgd_probe_ap+0x81/0xc0 [mac80211]
4472 Nov 09 09:58:05 ct523c-2103 kernel:  cfg80211_wiphy_work+0x8c/0xb0 [cfg80211]
4473 Nov 09 09:58:05 ct523c-2103 kernel:  process_one_work+0x15d/0x330
4474 Nov 09 09:58:05 ct523c-2103 kernel:  worker_thread+0x2e8/0x400
4475 Nov 09 09:58:05 ct523c-2103 kernel:  ? rescuer_thread+0x400/0x400
4476 Nov 09 09:58:05 ct523c-2103 kernel:  kthread+0xdc/0x110
4477 Nov 09 09:58:05 ct523c-2103 kernel:  ? kthread_complete_and_exit+0x20/0x20
4478 Nov 09 09:58:05 ct523c-2103 kernel:  ret_from_fork+0x28/0x40
4479 Nov 09 09:58:05 ct523c-2103 kernel:  ? kthread_complete_and_exit+0x20/0x20
4480 Nov 09 09:58:05 ct523c-2103 kernel:  ret_from_fork_asm+0x11/0x20
4481 Nov 09 09:58:05 ct523c-2103 kernel:  </TASK>
4482 Nov 09 09:58:05 ct523c-2103 kernel: ---[ end trace 0000000000000000 ]---

Thanks,
Ben

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com