Re: 6.15-rc1/regression/bisected - commit 9dd05df8403b introduced a new warning when I unload mt7921e module

On Mon, 2025-05-12 at 04:11 +0500, Mikhail Gavrilov wrote:

 

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On Thu, Apr 10, 2025 at 3:54 AM Mikhail Gavrilov
[off-list ref] wrote:

quoted

Hi,
Probably I wouldn't have paid attention to this because in real
life I
did not need to unload module mt7921e.
But after commit 9dd05df8403b (thanks to git bisect), I see
"warning"
on every system shutdown and reboot.

Of course, an annoying warning could be reproduced with a simple
command:
# rmmod mt7921e

Leads to stacktrace:
[  182.293388] ------------[ cut here ]------------
[  182.293515] WARNING: CPU: 28 PID: 4057 at net/core/dev.c:7295
__netif_napi_del_locked+0x340/0x420
[  182.293527] Modules linked in: uinput rfcomm snd_seq_dummy
snd_hrtimer nft_queue nfnetlink_queue nf_conntrack_netbios_ns
nf_conntrack_broadcast 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 ip_set qrtr bnep sunrpc binfmt_misc amd_atl
intel_rapl_msr
intel_rapl_common snd_hda_codec_realtek snd_hda_codec_generic
mt7921e(-) snd_hda_scodec_component snd_hda_codec_hdmi
mt7921_common
btusb edac_mce_amd btrtl mt792x_lib btintel mt76_connac_lib
snd_hda_intel btbcm snd_intel_dspcfg mt76 btmtk snd_intel_sdw_acpi
bluetooth kvm_amd snd_hda_codec vfat mac80211 fat snd_hda_core kvm
snd_hwdep snd_seq snd_seq_device spd5118 libarc4 snd_pcm r8169
wmi_bmof rapl i2c_piix4 snd_timer cfg80211 pcspkr k10temp i2c_smbus
snd rfkill realtek soundcore joydev gpio_amdpt gpio_generic loop
nfnetlink zram lz4hc_compress lz4_compress amdgpu amdxcp
i2c_algo_bit
drm_ttm_helper ttm drm_exec gpu_sched nvme
[  182.293683]  drm_suballoc_helper polyval_clmulni polyval_generic
drm_panel_backlight_quirks ghash_clmulni_intel drm_buddy ucsi_ccg
sha512_ssse3 drm_display_helper nvme_core typec_ucsi sha256_ssse3
sha1_ssse3 typec nvme_keyring sp5100_tco cec nvme_auth video wmi
fuse
[  182.293750] CPU: 28 UID: 0 PID: 4057 Comm: rmmod Tainted: G
W    L     ------  ---  6.15.0-0.rc1.15.fc43.x86_64+debug #1
PREEMPT(lazy)
[  182.293758] Tainted: [W]=WARN, [L]=SOFTLOCKUP
[  182.293762] Hardware name: ASRock B650I Lightning WiFi/B650I
Lightning WiFi, BIOS 3.08 09/18/2024
[  182.293766] RIP: 0010:__netif_napi_del_locked+0x340/0x420
[  182.293772] Code: 0f 85 f2 00 00 00 48 8b 43 30 be ff ff ff ff
48
8d b8 b8 0d 00 00 e8 bf 73 a0 00 85 c0 0f 85 17 fd ff ff 0f 0b e9
10
fd ff ff <0f> 0b e9 5b fd ff ff 48 c7 c7 f4 ad ab b0 e8 dd 77 f5 fd
e9
ea fc
[  182.293777] RSP: 0018:ffffc90029ccf958 EFLAGS: 00010246
[  182.293783] RAX: 0000000000000020 RBX: ffff88824f177f88 RCX:
0000000000000001
[  182.293787] RDX: 1ffff11049e2eff3 RSI: 0000000000000008 RDI:
ffff88824f177f98
[  182.293790] RBP: ffff88824f177f98 R08: ffffffffad1e2bdb R09:
ffffed1049e2eff3
[  182.293794] R10: ffffed1049e2eff4 R11: 000000004bdb515b R12:
ffff88824f1766c8
[  182.293797] R13: ffff88824f173320 R14: ffff88811189c000 R15:
dffffc0000000000
[  182.293800] FS:  00007f1b21ce4740(0000)
GS:ffff889028978000(0000)
knlGS:0000000000000000
[  182.293805] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  182.293808] CR2: 00007f94de36efe8 CR3: 000000023c9e6000 CR4:
0000000000f50ef0
[  182.293812] PKRU: 55555554
[  182.293816] Call Trace:
[  182.293819]  <TASK>
[  182.293825]  mt76_dma_cleanup+0xbd/0x7c0 [mt76]
[  182.293845]  mt7921_pci_remove+0x180/0x340 [mt7921e]
[  182.293854]  pci_device_remove+0xad/0x210
[  182.293862]  device_release_driver_internal+0x36d/0x520
[  182.293871]  driver_detach+0xc4/0x1a0
[  182.293878]  bus_remove_driver+0x11c/0x2a0
[  182.293886]  pci_unregister_driver+0x2a/0x250
[  182.293891]  ? find_module_all+0xec/0x120
[  182.293900]  __do_sys_delete_module+0x36a/0x580
[  182.293905]  ? __pfx___call_rcu_common.constprop.0+0x10/0x10
[  182.293912]  ? __pfx___do_sys_delete_module+0x10/0x10
[  182.293922]  ? kmem_cache_free+0x3ca/0x570
[  182.293937]  do_syscall_64+0x96/0x1a0
[  182.293946]  ? lockdep_hardirqs_on+0x8c/0x130
[  182.293951]  ? do_syscall_64+0xa3/0x1a0
[  182.293955]  ? do_syscall_64+0xa3/0x1a0
[  182.293961]  ? mark_usage+0x65/0x180
[  182.293967]  ? local_clock+0x15/0x30
[  182.293971]  ? __lock_acquire+0x40f/0x1160
[  182.293976]  ? __lock_release.isra.0+0xb2/0x340
[  182.293981]  ? __pfx___handle_mm_fault+0x10/0x10
[  182.293991]  ? find_held_lock+0x2b/0x80
[  182.293999]  ? __lock_release.isra.0+0x1cb/0x340
[  182.294009]  ? __lock_release.isra.0+0x1cb/0x340
[  182.294018]  ? do_user_addr_fault+0x4b1/0xa60
[  182.294030]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[  182.294034] RIP: 0033:0x7f1b21503efb
[  182.294049] Code: 73 01 c3 48 8b 0d 05 1f 0f 00 f7 d8 64 89 01
48
83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 b0 00
00
00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d d5 1e 0f 00 f7 d8 64
89
01 48
[  182.294053] RSP: 002b:00007ffff1a01668 EFLAGS: 00000202
ORIG_RAX:
00000000000000b0
[  182.294059] RAX: ffffffffffffffda RBX: 000056276dc577a0 RCX:
00007f1b21503efb
[  182.294063] RDX: 0000000000000000 RSI: 0000000000000800 RDI:
000056276dc57800
[  182.294066] RBP: 00007ffff1a01690 R08: 0000000000000000 R09:
0000000000000000
[  182.294069] R10: 0000000000000000 R11: 0000000000000202 R12:
0000000000000000
[  182.294073] R13: 00007ffff1a01d86 R14: 00007ffff1a018e0 R15:
0000000000000000
[  182.294085]  </TASK>
[  182.294088] irq event stamp: 55129
[  182.294091] hardirqs last  enabled at (55137):
[<ffffffffaa834afe>]
__up_console_sem+0x7e/0x90
[  182.294097] hardirqs last disabled at (55144):
[<ffffffffaa834ae3>]
__up_console_sem+0x63/0x90
[  182.294102] softirqs last  enabled at (52944):
[<ffffffffaa613062>]
handle_softirqs+0x592/0x860
[  182.294108] softirqs last disabled at (52937):
[<ffffffffaa613466>]
__irq_exit_rcu+0x126/0x240
[  182.294113] ---[ end trace 0000000000000000 ]---
[  209.265604] workqueue: gc_worker [nf_conntrack] hogged CPU for

quoted

10000us 11 times, consider switching to WQ_UNBOUND

commit 9dd05df8403bda5b68178b795c554b3940628bb6
Author: Jakub Kicinski [off-list ref]
Date:   Mon Feb 3 13:58:16 2025 -0800

    net: warn if NAPI instance wasn't shut down
....
    Drivers should always disable a NAPI instance before removing
it.
    If they don't the instance may be queued for polling.
    Since commit 86e25f40aa1e ("net: napi: Add napi_config")
    we also remove the NAPI from the busy polling hash table
    in napi_disable(), so not disabling would leave a stale
    entry there.
....
    Use of busy polling is relatively uncommon so bugs may be
lurking
    in the drivers. Add an explicit warning.
....
    Reviewed-by: Joe Damato [off-list ref]
    Reviewed-by: Eric Dumazet [off-list ref]
    Link:
https://patch.msgid.link/20250203215816.1294081-1-kuba@kernel.org (local)
    Signed-off-by: Jakub Kicinski [off-list ref]

 net/core/dev.c | 3 +++
 1 file changed, 3 insertions(+)

In the commit annotation I see that it was done on purpose so that
those responsible would fix their module themselves, right?

Who could look into it? Deren?

My machine spec: https://linux-hardware.org/?probe=fa0da30b11
And I attached below my build config and full kernel log.

quoted

sh /usr/src/kernels/(uname -r)/scripts/faddr2line
/lib/debug/lib/modules/(uname -
r)/kernel/drivers/net/wireless/mediatek/mt76/mt76.ko.debug
mt76_dma_cleanup+0xbd

mt76_dma_cleanup+0xbd/0x7c0:
__netif_napi_del at /usr/src/debug/kernel-6.15-rc5-136-
g9c69f8884904/linux-6.15.0-
0.rc5.250509g9c69f8884904.47.fc43.x86_64/./include/linux/netdevice.h:
2877
(inlined by) netif_napi_del at /usr/src/debug/kernel-6.15-rc5-136-
g9c69f8884904/linux-6.15.0-
0.rc5.250509g9c69f8884904.47.fc43.x86_64/./include/linux/netdevice.h:
2894
(inlined by) mt76_dma_cleanup at /usr/src/debug/kernel-6.15-rc5-136-
g9c69f8884904/linux-6.15.0-
0.rc5.250509g9c69f8884904.47.fc43.x86_64/drivers/net/wireless/mediate
k/mt76/dma.c:1014



Excuse me, there's very little time left before the 6.15 release.
Perhaps it's time to address this regression?

-- 


Best Regards,
Mike Gavrilov.

This issue has been resolved by Fedor. We may take this as the
solution.
https://patchwork.kernel.org/project/linux-wireless/patch/20250506115540.19045-1-pchelkin@ispras.ru/


Hi Jakub, Felix,

We have tested this patch and it works well for mt7921e driver. Can you
please help to pick this patch for 6.15 release?


Regards,
Deren