diff mbox series

wifi: iwlwifi: Add debugging around scan failure warning.

Message ID 20231114212309.2180281-1-greearb@candelatech.com (mailing list archive)
State New
Delegated to: Miri Korenblit
Headers show
Series wifi: iwlwifi: Add debugging around scan failure warning. | expand

Commit Message

Ben Greear Nov. 14, 2023, 9:23 p.m. UTC 
From: Ben Greear <greearb@candelatech.com>

Provide additional information that may help debugging why
the WARN_ON is seen.

Signed-off-by: Ben Greear <greearb@candelatech.com>
---
 drivers/net/wireless/intel/iwlwifi/mvm/scan.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Comments

Johannes Berg Nov. 15, 2023, 8:57 a.m. UTC | #1 
On Tue, 2023-11-14 at 13:23 -0800, greearb@candelatech.com wrote:
> From: Ben Greear <greearb@candelatech.com>
> 
> Provide additional information that may help debugging why
> the WARN_ON is seen.
> 
> Signed-off-by: Ben Greear <greearb@candelatech.com>
> ---
>  drivers/net/wireless/intel/iwlwifi/mvm/scan.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/scan.c b/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
> index 75c5c58e14a5..ec24ece7c877 100644
> --- a/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
> +++ b/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
> @@ -2356,7 +2356,10 @@ iwl_mvm_scan_umac_fill_general_p_v12(struct iwl_mvm *mvm,
>  			link_id = ffs(vif->active_links) - 1;
>  
>  		link_info = scan_vif->link[link_id];
> -		if (!WARN_ON(!link_info))
> +		if (WARN_ON(!link_info))
> +			IWL_ERR(mvm, "scan failure: Cannot find link info for link-id: %d active-links: 0x%x\n",
> +				link_id, vif->active_links);
> 

It would make sense to put the data *into* the warning, rather than
separately? Though I'm not sure I see so much value in the long string
(vs. just the data).

But honestly I'm not sure this really even is a problem at all? Some
confusion can happen during firmware restart here, and not sure we can
really fix that. Though maybe with the new locking we can.

johannes
Ben Greear Nov. 15, 2023, 4:01 p.m. UTC | #2 
On 11/15/23 00:57, Johannes Berg wrote:
> On Tue, 2023-11-14 at 13:23 -0800, greearb@candelatech.com wrote:
>> From: Ben Greear <greearb@candelatech.com>
>>
>> Provide additional information that may help debugging why
>> the WARN_ON is seen.
>>
>> Signed-off-by: Ben Greear <greearb@candelatech.com>
>> ---
>>   drivers/net/wireless/intel/iwlwifi/mvm/scan.c | 5 ++++-
>>   1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/scan.c b/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
>> index 75c5c58e14a5..ec24ece7c877 100644
>> --- a/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
>> +++ b/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
>> @@ -2356,7 +2356,10 @@ iwl_mvm_scan_umac_fill_general_p_v12(struct iwl_mvm *mvm,
>>   			link_id = ffs(vif->active_links) - 1;
>>   
>>   		link_info = scan_vif->link[link_id];
>> -		if (!WARN_ON(!link_info))
>> +		if (WARN_ON(!link_info))
>> +			IWL_ERR(mvm, "scan failure: Cannot find link info for link-id: %d active-links: 0x%x\n",
>> +				link_id, vif->active_links);
>>
> 
> It would make sense to put the data *into* the warning, rather than
> separately? Though I'm not sure I see so much value in the long string
> (vs. just the data).

I assume IWL_ERR will provide some extra context in systems with multiple radios,
so more useful than what I could easily put into WARN_* directly.

> 
> But honestly I'm not sure this really even is a problem at all? Some
> confusion can happen during firmware restart here, and not sure we can
> really fix that. Though maybe with the new locking we can.

I see the splat, not sure why.  It would be nice to know if link-id is
corrupted somehow, or if active links is zero, etc.

Thanks,
Ben

> 
> johannes
>
Johannes Berg Nov. 15, 2023, 4:10 p.m. UTC | #3 
On Wed, 2023-11-15 at 08:01 -0800, Ben Greear wrote:
> On 11/15/23 00:57, Johannes Berg wrote:
> > On Tue, 2023-11-14 at 13:23 -0800, greearb@candelatech.com wrote:
> > > From: Ben Greear <greearb@candelatech.com>
> > > 
> > > Provide additional information that may help debugging why
> > > the WARN_ON is seen.
> > > 
> > > Signed-off-by: Ben Greear <greearb@candelatech.com>
> > > ---
> > >   drivers/net/wireless/intel/iwlwifi/mvm/scan.c | 5 ++++-
> > >   1 file changed, 4 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/scan.c b/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
> > > index 75c5c58e14a5..ec24ece7c877 100644
> > > --- a/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
> > > +++ b/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
> > > @@ -2356,7 +2356,10 @@ iwl_mvm_scan_umac_fill_general_p_v12(struct iwl_mvm *mvm,
> > >   			link_id = ffs(vif->active_links) - 1;
> > >   
> > >   		link_info = scan_vif->link[link_id];
> > > -		if (!WARN_ON(!link_info))
> > > +		if (WARN_ON(!link_info))
> > > +			IWL_ERR(mvm, "scan failure: Cannot find link info for link-id: %d active-links: 0x%x\n",
> > > +				link_id, vif->active_links);
> > > 
> > 
> > It would make sense to put the data *into* the warning, rather than
> > separately? Though I'm not sure I see so much value in the long string
> > (vs. just the data).
> 
> I assume IWL_ERR will provide some extra context in systems with multiple radios,
> so more useful than what I could easily put into WARN_* directly.

That's true, though not sure that helps so much more? You could put it
easily into the warning though :)

Anyway, the point is that bug reports from the field often don't include
the full log etc. so putting things _into_ the warning really is usually
more useful than putting it after.

> > 
> > But honestly I'm not sure this really even is a problem at all? Some
> > confusion can happen during firmware restart here, and not sure we can
> > really fix that. Though maybe with the new locking we can.
> 
> I see the splat, not sure why.  It would be nice to know if link-id is
> corrupted somehow, or if active links is zero, etc.

Yeah in this case we'd really need more of the dynamic information to
really debug it, I guess.

johannes
Ben Greear Nov. 16, 2023, 5:51 p.m. UTC | #4 
On 11/15/23 08:10, Johannes Berg wrote:
> On Wed, 2023-11-15 at 08:01 -0800, Ben Greear wrote:
>> On 11/15/23 00:57, Johannes Berg wrote:
>>> On Tue, 2023-11-14 at 13:23 -0800, greearb@candelatech.com wrote:
>>>> From: Ben Greear <greearb@candelatech.com>
>>>>
>>>> Provide additional information that may help debugging why
>>>> the WARN_ON is seen.
>>>>
>>>> Signed-off-by: Ben Greear <greearb@candelatech.com>
>>>> ---
>>>>    drivers/net/wireless/intel/iwlwifi/mvm/scan.c | 5 ++++-
>>>>    1 file changed, 4 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/scan.c b/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
>>>> index 75c5c58e14a5..ec24ece7c877 100644
>>>> --- a/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
>>>> +++ b/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
>>>> @@ -2356,7 +2356,10 @@ iwl_mvm_scan_umac_fill_general_p_v12(struct iwl_mvm *mvm,
>>>>    			link_id = ffs(vif->active_links) - 1;
>>>>    
>>>>    		link_info = scan_vif->link[link_id];
>>>> -		if (!WARN_ON(!link_info))
>>>> +		if (WARN_ON(!link_info))
>>>> +			IWL_ERR(mvm, "scan failure: Cannot find link info for link-id: %d active-links: 0x%x\n",
>>>> +				link_id, vif->active_links);
>>>>
>>>
>>> It would make sense to put the data *into* the warning, rather than
>>> separately? Though I'm not sure I see so much value in the long string
>>> (vs. just the data).
>>
>> I assume IWL_ERR will provide some extra context in systems with multiple radios,
>> so more useful than what I could easily put into WARN_* directly.
> 
> That's true, though not sure that helps so much more? You could put it
> easily into the warning though :)
> 
> Anyway, the point is that bug reports from the field often don't include
> the full log etc. so putting things _into_ the warning really is usually
> more useful than putting it after.
> 
>>>
>>> But honestly I'm not sure this really even is a problem at all? Some
>>> confusion can happen during firmware restart here, and not sure we can
>>> really fix that. Though maybe with the new locking we can.
>>
>> I see the splat, not sure why.  It would be nice to know if link-id is
>> corrupted somehow, or if active links is zero, etc.
> 
> Yeah in this case we'd really need more of the dynamic information to
> really debug it, I guess.

I found a splat with my debugging enabled today, running with the v86 firmware.  Looks like
immediate cause is that active_links was 0x0.  Logs are full of it, in fact.  Seems to always
be the same reason.

[ 4381.954574] cfg80211-scan-6ghz, n-channels is 0, flags: 0x4000  need_scan_psc: 1 req-n-channels: 2
[ 4382.599873] ------------[ cut here ]------------
[ 4382.599880] WARNING: CPU: 3 PID: 6083 at drivers/net/wireless/intel/iwlwifi/mvm/scan.c:2359 iwl_mvm_scan_umac_v14_and_above+0x169a/0x1730 [iwlmvm]
[ 4382.599950] 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 snd_hda_codec_hdmi ee1004 intel_pmc_bxt snd_hda_codec_realtek snd_hda_codec_generic 
iTCO_vendor_support ledtrig_audio coretemp intel_rapl_common intel_tcc_cooling snd_hda_intel x86_pkg_temp_thermal snd_intel_dspcfg intel_powerclamp 
snd_hda_codec snd_hda_core snd_hwdep snd_seq snd_seq_device kvm_intel snd_pcm kvm irqbypass intel_wmi_thunderbolt snd_timer snd i2c_i801 pcspkr soundcore 
i2c_smbus iwlmvm mac80211 iwlwifi cfg80211 bfq mei_pxp mei_hdcp intel_pch_thermal tpm_crb tpm_tis tpm_tis_core tpm acpi_pad sch_fq_codel nfsd auth_rpcgss 
nfs_acl lockd grace fuse sunrpc zram raid1 dm_raid raid456 libcrc32c async_raid6_recov async_memcpy async_pq async_xor xor async_tx raid6_pq i915 drm_buddy 
intel_gtt drm_display_helper igb drm_kms_helper i2c_algo_bit cec rc_core ttm ixgbe mdio dca drm agpgart
[ 4382.600146]  hwmon mei_wdt xhci_pci i2c_core xhci_pci_renesas video wmi [last unloaded: nfnetlink]
[ 4382.600167] CPU: 3 PID: 6083 Comm: wpa_supplicant Tainted: G        W          6.7.0-rc1+ #3
[ 4382.600173] Hardware name: Default string Default string/SKYBAY, BIOS 5.12 02/21/2023
[ 4382.600177] RIP: 0010:iwl_mvm_scan_umac_v14_and_above+0x169a/0x1730 [iwlmvm]
[ 4382.600240] Code: 8b 84 24 28 01 00 00 48 0f ba e0 2f 0f 83 9a fe ff ff 41 83 ce 04 e9 91 fe ff ff e8 50 63 c2 df b8 80 ff ff ff e9 ec f7 ff ff <0f> 0b 4c 89 
ff e8 7c 65 c2 df 49 8b 3f 45 0f b7 c4 89 e9 48 c7 c2
[ 4382.600245] RSP: 0018:ffff88814342ed18 EFLAGS: 00010246
[ 4382.600251] RAX: 0000000000000000 RBX: ffff88814c0ef198 RCX: ffffffffa19e4a83
[ 4382.600256] RDX: dffffc0000000000 RSI: 0000000000000003 RDI: ffff88814c0efa80
[ 4382.600259] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed102b98cd01
[ 4382.600263] R10: 0000000000000000 R11: 6048302418120c08 R12: 0000000000000000
[ 4382.600267] R13: 0000000000000000 R14: 0000000000000000 R15: ffff88814b1454e8
[ 4382.600271] FS:  00007f32fbf4b780(0000) GS:ffff88841bf80000(0000) knlGS:0000000000000000
[ 4382.600276] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 4382.600280] CR2: 00007f604e9faa50 CR3: 00000001a07b2001 CR4: 00000000003706f0
[ 4382.600284] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 4382.600288] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 4382.600291] Call Trace:
[ 4382.600295]  <TASK>
[ 4382.600299]  ? __warn+0x9c/0x1f0
[ 4382.600307]  ? iwl_mvm_scan_umac_v14_and_above+0x169a/0x1730 [iwlmvm]
[ 4382.600384]  ? report_bug+0x1aa/0x1e0
[ 4382.600393]  ? handle_bug+0x41/0x80
[ 4382.600398]  ? exc_invalid_op+0x13/0x40
[ 4382.600404]  ? asm_exc_invalid_op+0x16/0x20
[ 4382.600413]  ? iwl_mvm_scan_umac_v14_and_above+0x13e3/0x1730 [iwlmvm]
[ 4382.600475]  ? iwl_mvm_scan_umac_v14_and_above+0x169a/0x1730 [iwlmvm]
[ 4382.600536]  ? iwl_mvm_scan_umac_v14_and_above+0x13e3/0x1730 [iwlmvm]
[ 4382.600597]  ? desc_read_finalized_seq+0x69/0xf0
[ 4382.600604]  ? desc_read+0x190/0x190
[ 4382.600609]  ? rcu_is_watching+0x1f/0x40
[ 4382.600615]  ? lock_acquire+0xc4/0x3b0
[ 4382.600621]  ? rcu_is_watching+0x1f/0x40
[ 4382.600627]  ? __iwl_info+0x1e0/0x1e0 [iwlwifi]
[ 4382.600690]  ? ieee80211_iterate_active_interfaces_atomic+0x78/0x100 [mac80211]
[ 4382.600849]  ? __iterate_interfaces+0x12e/0x220 [mac80211]
[ 4382.601000]  ? iwl_mvm_scan_umac_chan_flags_v2+0x2c0/0x2c0 [iwlmvm]
[ 4382.601063]  ? iwl_wait_stats_complete+0x30/0x30 [iwlmvm]
[ 4382.601125]  iwl_mvm_build_scan_cmd+0xb21/0x2110 [iwlmvm]
[ 4382.601190]  ? iwl_mvm_scan_umac_v12+0x530/0x530 [iwlmvm]
[ 4382.601253]  ? iwl_mvm_build_scan_probe+0x39e/0x550 [iwlmvm]
[ 4382.601316]  iwl_mvm_reg_scan_start+0x77a/0xa10 [iwlmvm]
[ 4382.601388]  ? iwl_mvm_check_running_scans+0x130/0x130 [iwlmvm]
[ 4382.601449]  ? stack_access_ok+0x40/0xf0
[ 4382.601482]  ? ieee80211_scan_accept_presp+0xb0/0xb0 [mac80211]
[ 4382.601623]  ? kasan_unpoison+0x23/0x50
[ 4382.601632]  iwl_mvm_mac_hw_scan+0x81/0xa0 [iwlmvm]
[ 4382.601689]  drv_hw_scan+0x15e/0x2f0 [mac80211]
[ 4382.601834]  __ieee80211_start_scan+0x5bf/0xb10 [mac80211]
[ 4382.601977]  ? drv_hw_scan+0x2f0/0x2f0 [mac80211]
[ 4382.602117]  ? __kasan_kmalloc+0x83/0x90
[ 4382.602122]  ? rcu_is_watching+0x1f/0x40
[ 4382.602128]  ? __kmalloc+0xd7/0x150
[ 4382.602136]  rdev_scan+0x6d/0x1d0 [cfg80211]
[ 4382.602276]  nl80211_trigger_scan+0x673/0xd10 [cfg80211]
[ 4382.602426]  genl_family_rcv_msg_doit+0x151/0x1d0
[ 4382.602435]  ? genl_family_rcv_msg_attrs_parse.constprop.0+0x120/0x120
[ 4382.602444]  ? cap_capable+0x9a/0xd0
[ 4382.602451]  ? security_capable+0x29/0x60
[ 4382.602458]  genl_rcv_msg+0x281/0x3b0
[ 4382.602465]  ? genl_family_rcv_msg_dumpit+0x1e0/0x1e0
[ 4382.602471]  ? set_track_prepare+0x3b/0x60
[ 4382.602477]  ? kmalloc_reserve+0xa3/0x120
[ 4382.602482]  ? __alloc_skb+0xcb/0x210
[ 4382.602487]  ? nl80211_assoc_bss+0xf0/0xf0 [cfg80211]
[ 4382.602627]  ? nl80211_send_scan_start+0xd0/0xd0 [cfg80211]
[ 4382.602765]  ? cfg80211_external_auth_request+0x340/0x340 [cfg80211]
[ 4382.602901]  ? do_syscall_64+0x3b/0x110
[ 4382.602906]  ? entry_SYSCALL_64_after_hwframe+0x46/0x4e
[ 4382.602913]  ? ____sys_sendmsg+0x3e6/0x470
[ 4382.602918]  ? ___sys_sendmsg+0xdc/0x140
[ 4382.602926]  netlink_rcv_skb+0xcf/0x210
[ 4382.602931]  ? lock_sync+0xf0/0xf0
[ 4382.602936]  ? genl_family_rcv_msg_dumpit+0x1e0/0x1e0
[ 4382.602943]  ? netlink_ack+0x840/0x840
[ 4382.602954]  ? rwsem_down_read_slowpath+0x920/0x920
[ 4382.602960]  ? netlink_deliver_tap+0x9f/0x630
[ 4382.602965]  ? netlink_deliver_tap+0xf9/0x630
[ 4382.602973]  genl_rcv+0x1f/0x30
[ 4382.602978]  netlink_unicast+0x2ee/0x490
[ 4382.602985]  ? netlink_attachskb+0x430/0x430
[ 4382.602990]  ? __virt_addr_valid+0xab/0x130
[ 4382.602996]  ? check_stack_object+0x1d/0x60
[ 4382.603003]  ? __check_object_size+0x22c/0x3b0
[ 4382.603010]  netlink_sendmsg+0x3ca/0x6f0
[ 4382.603018]  ? netlink_unicast+0x490/0x490
[ 4382.603025]  ? import_ubuf+0xa9/0xd0
[ 4382.603032]  ? __import_iovec+0x256/0x290
[ 4382.603038]  ? netlink_unicast+0x490/0x490
[ 4382.603044]  __sock_sendmsg+0x6e/0xb0
[ 4382.603050]  ____sys_sendmsg+0x3e6/0x470
[ 4382.603056]  ? kernel_sendmsg+0x30/0x30
[ 4382.603061]  ? __copy_msghdr+0x1a0/0x1a0
[ 4382.603069]  ? up_write+0xfb/0x2d0
[ 4382.603076]  ___sys_sendmsg+0xdc/0x140
[ 4382.603082]  ? __ia32_sys_recvmmsg+0x160/0x160
[ 4382.603089]  ? netlink_setsockopt+0x2da/0x420
[ 4382.603096]  ? netlink_realloc_groups+0x180/0x180
[ 4382.603101]  ? reacquire_held_locks+0x270/0x270
[ 4382.603108]  ? sock_do_ioctl+0xaf/0x180
[ 4382.603114]  ? rcu_is_watching+0x1f/0x40
[ 4382.603120]  ? do_sock_setsockopt+0x162/0x2a0
[ 4382.603125]  ? move_addr_to_user+0xf0/0xf0
[ 4382.603133]  ? __fget_light+0xd2/0xf0
[ 4382.603141]  __sys_sendmsg+0xc4/0x150
[ 4382.603146]  ? __sys_sendmsg_sock+0x10/0x10
[ 4382.603152]  ? __sys_setsockopt+0x119/0x190
[ 4382.603158]  ? __ia32_sys_recv+0x60/0x60
[ 4382.603167]  ? lockdep_hardirqs_on_prepare+0xe/0x200
[ 4382.603174]  ? syscall_enter_from_user_mode+0x1c/0x50
[ 4382.603180]  ? trace_hardirqs_on+0x12/0xe0
[ 4382.603188]  do_syscall_64+0x3b/0x110
[ 4382.603193]  entry_SYSCALL_64_after_hwframe+0x46/0x4e
[ 4382.603199] RIP: 0033:0x7f32fb713737
[ 4382.603203] Code: 0e 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 
ff ff 77 51 c3 48 83 ec 28 89 54 24 1c 48 89 74 24 10
[ 4382.603208] RSP: 002b:00007ffd9313fc08 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[ 4382.603215] RAX: ffffffffffffffda RBX: 0000000001dabc00 RCX: 00007f32fb713737
[ 4382.603219] RDX: 0000000000000000 RSI: 00007ffd9313fc60 RDI: 0000000000000007
[ 4382.603223] RBP: 0000000001e43e40 R08: 0000000000000004 R09: 00000000000000f0
[ 4382.603227] R10: 00007ffd9313fd24 R11: 0000000000000246 R12: 0000000001dabb10
[ 4382.603230] R13: 00007ffd9313fc60 R14: 000000000079cd98 R15: 00007f32fc093000
[ 4382.603239]  </TASK>
[ 4382.603243] irq event stamp: 0
[ 4382.603246] hardirqs last  enabled at (0): [<0000000000000000>] 0x0
[ 4382.603250] hardirqs last disabled at (0): [<ffffffff811d9d28>] copy_process+0xf68/0x32f0
[ 4382.603257] softirqs last  enabled at (0): [<ffffffff811d9d28>] copy_process+0xf68/0x32f0
[ 4382.603262] softirqs last disabled at (0): [<0000000000000000>] 0x0
[ 4382.603266] ---[ end trace 0000000000000000 ]---
[ 4382.603271] iwlwifi 0000:21:00.0: scan failure: Cannot find link info for link-id: 0 active-links: 0x0
[ 4382.611303] iwlwifi 0000:21:00.0: Scan failed! ret -5
[ 4382.615098] wlan15: _ieee80211_start_scan had failure code: -5
[ 4382.615103] scan: cfg80211_scan failed: -5
[ 4383.282455] wlan5: do_stop, canceling dfs-cac-timer-work.

Thanks,
Ben
Johannes Berg Nov. 16, 2023, 8:05 p.m. UTC | #5 
On Thu, 2023-11-16 at 09:51 -0800, Ben Greear wrote:

> I found a splat with my debugging enabled today, running with the v86 firmware.  Looks like
> immediate cause is that active_links was 0x0.  Logs are full of it, in fact.  Seems to always
> be the same reason.

active_links will be 0 if there isn't MLO, i.e. you're not connected.

> [ 4382.603271] iwlwifi 0000:21:00.0: scan failure: Cannot find link info for link-id: 0 active-links: 0x0
> 

The real question is how we ended up with no info for link-id 0, but
like I said, that's a more dynamic question, just knowing the number
doesn't really help with it :)

johannes
diff mbox series

Patch

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/scan.c b/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
index 75c5c58e14a5..ec24ece7c877 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
@@ -2356,7 +2356,10 @@  iwl_mvm_scan_umac_fill_general_p_v12(struct iwl_mvm *mvm,
 			link_id = ffs(vif->active_links) - 1;
 
 		link_info = scan_vif->link[link_id];
-		if (!WARN_ON(!link_info))
+		if (WARN_ON(!link_info))
+			IWL_ERR(mvm, "scan failure: Cannot find link info for link-id: %d active-links: 0x%x\n",
+				link_id, vif->active_links);
+		else
 			gp->scan_start_mac_or_link_id = link_info->fw_link_id;
 	}
 }