Message-ID: <2b25a988-6965-48e4-a788-58dd8a776e06@leemhuis.info>
Date: Wed, 23 Oct 2024 12:22:22 +0200
From: "Linux regression tracking (Thorsten Leemhuis)"
 <regressions@...mhuis.info>
To: Frederic Weisbecker <frederic@...nel.org>,
 Linux regressions mailing list <regressions@...ts.linux.dev>
Cc: LKML <linux-kernel@...r.kernel.org>, Mingcong Bai <jeffbai@...c.io>,
 "Paul E. McKenney" <paulmck@...nel.org>, rcu <rcu@...r.kernel.org>
Subject: Re: [Regression] wifi problems since tg3 started throwing rcu stall
 warnings

On 23.10.24 12:09, Frederic Weisbecker wrote:
> Le Wed, Oct 23, 2024 at 10:27:18AM +0200, Linux regression tracking (Thorsten Leemhuis) a écrit :
>> Hi, Thorsten here, the Linux kernel's regression tracker.
>>
>> Frederic, I noticed a report about a regression in bugzilla.kernel.org
>> that appears to be caused by the following change of yours:
>>
>> 55d4669ef1b768 ("rcu: Fix rcu_barrier() VS post CPUHP_TEARDOWN_CPU
>> invocation")

> Are you sure about the commit? Below it says:

Not totally, but...

>> As many (most?) kernel developers don't keep an eye on the bug tracker,
>> I decided to write this mail. To quote from
>> https://bugzilla.kernel.org/show_bug.cgi?id=219390:
>>
>>>  Mingcong Bai 2024-10-15 13:32:35 UTC
>>>
>>> Since aa162aa4aa383a0a714b1c36e8fcc77612ddd1a2 between v6.10.4 and
> 
> Now that's aa162aa4aa383a0a714b1c36e8fcc77612ddd1a2 which I can't find in vanilla
> tree.

...quite, as that is the commit-id of the backport to v6.10.5; and the
reporter reverted it there. Ideally of course that would have happened
on recent mainline. If you doubt, ask Mingcong Bai to check if a revert
there helps, too.

HTH, Ciao, Thorsten

> Also I'm failing to see an immediate issue between the below stacktrace
> and the above commit. So are we sure about that reference?
> 
> Thanks.
> 
> 
>>> v6.10.5, the Broadcom Tigon3 Ethernet interface (tg3) found on Apple
>>> MacBook Pro (15'', Mid 2010) would throw many rcu stall errors during
>>> boot up, causing peripherals such as the wireless card to misbehave:
>>>
>>> [   24.153855] rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 2-.... } 21 jiffies s: 973 root: 0x4/.
>>> [   24.166938] rcu: blocking rcu_node structures (internal RCU debug):
>>> [   24.177800] Sending NMI from CPU 3 to CPUs 2:
>>> [   24.183113] NMI backtrace for cpu 2
>>> [   24.183119] CPU: 2 PID: 1049 Comm: NetworkManager Not tainted 6.10.5-aosc-main #1
>>> [   24.183123] Hardware name: Apple Inc. MacBookPro6,2/Mac-F22586C8, BIOS    MBP61.88Z.005D.B00.1804100943 04/10/18
>>> [   24.183125] RIP: 0010:__this_module+0x2d3d1/0x4f310 [tg3]
>>> [   24.183135] Code: c3 cc cc cc cc 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 0f 1f 44 00 00 89 f6 48 03 77 30 8b 06 <31> f6 31 ff c3 cc cc cc cc 66 0f 1f 44 00 00 90 90 90 90 90 90 90
>>> [   24.183138] RSP: 0018:ffffbf1a011d75e8 EFLAGS: 00000082
>>> [   24.183141] RAX: 0000000000000000 RBX: ffffa04ec78f8a00 RCX: 0000000000000000
>>> [   24.183143] RDX: 0000000000000000 RSI: ffffbf1a00fb007c RDI: ffffa04ec78f8a00
>>> [   24.183145] RBP: 0000000000000b50 R08: 0000000000000000 R09: 0000000000000000
>>> [   24.183147] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000216
>>> [   24.183148] R13: ffffbf1a011d7624 R14: ffffa04ec78f8a08 R15: ffffa04ec78f8b40
>>> [   24.183151] FS:  00007f4c524b2140(0000) GS:ffffa05007d00000(0000) knlGS:0000000000000000
>>> [   24.183153] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>> [   24.183155] CR2: 00007f7025eae3e8 CR3: 00000001040f8000 CR4: 00000000000006f0
>>> [   24.183157] Call Trace:
>>> [   24.183162]  <NMI>
>>> [   24.183167]  ? nmi_cpu_backtrace+0xbf/0x140
>>> [   24.183175]  ? nmi_cpu_backtrace_handler+0x11/0x20
>>> [   24.183181]  ? nmi_handle+0x61/0x160
>>> [   24.183186]  ? default_do_nmi+0x42/0x110
>>> [   24.183191]  ? exc_nmi+0x1bd/0x290
>>> [   24.183194]  ? end_repeat_nmi+0xf/0x53
>>> [   24.183203]  ? __this_module+0x2d3d1/0x4f310 [tg3]
>>> [   24.183207]  ? __this_module+0x2d3d1/0x4f310 [tg3]
>>> [   24.183210]  ? __this_module+0x2d3d1/0x4f310 [tg3]
>>> [   24.183213]  </NMI>
>>> [   24.183214]  <TASK>
>>> [   24.183215]  __this_module+0x31828/0x4f310 [tg3]
>>> [   24.183218]  ? __this_module+0x2d390/0x4f310 [tg3]
>>> [   24.183221]  __this_module+0x398e6/0x4f310 [tg3]
>>> [   24.183225]  __this_module+0x3baf8/0x4f310 [tg3]
>>> [   24.183229]  __this_module+0x4733f/0x4f310 [tg3]
>>> [   24.183233]  ? _raw_spin_unlock_irqrestore+0x25/0x70
>>> [   24.183237]  ? __this_module+0x398e6/0x4f310 [tg3]
>>> [   24.183241]  __this_module+0x4b943/0x4f310 [tg3]
>>> [   24.183244]  ? delay_tsc+0x89/0xf0
>>> [   24.183249]  ? preempt_count_sub+0x51/0x60
>>> [   24.183254]  __this_module+0x4be4b/0x4f310 [tg3]
>>> [   24.183258]  __dev_open+0x103/0x1c0
>>> [   24.183265]  __dev_change_flags+0x1bd/0x230
>>> [   24.183269]  ? rtnl_getlink+0x362/0x400
>>> [   24.183276]  dev_change_flags+0x26/0x70
>>> [   24.183280]  do_setlink+0xe16/0x11f0
>>> [   24.183286]  ? __nla_validate_parse+0x61/0xd40
>>> [   24.183295]  __rtnl_newlink+0x63d/0x9f0
>>> [   24.183301]  ? kmem_cache_alloc_node_noprof+0x12b/0x360
>>> [   24.183308]  ? kmalloc_trace_noprof+0x11e/0x350
>>> [   24.183312]  ? rtnl_newlink+0x2e/0x70
>>> [   24.183316]  rtnl_newlink+0x47/0x70
>>> [   24.183320]  rtnetlink_rcv_msg+0x152/0x400
>>> [   24.183324]  ? __netlink_sendskb+0x68/0x90
>>> [   24.183329]  ? netlink_unicast+0x237/0x290
>>> [   24.183333]  ? __pfx_rtnetlink_rcv_msg+0x10/0x10
>>> [   24.183336]  netlink_rcv_skb+0x5b/0x110
>>> [   24.183343]  netlink_unicast+0x1a4/0x290
>>> [   24.183347]  netlink_sendmsg+0x222/0x4a0
>>> [   24.183350]  ? proc_get_long.constprop.0+0x116/0x210
>>> [   24.183358]  ____sys_sendmsg+0x379/0x3b0
>>> [   24.183363]  ? copy_msghdr_from_user+0x6d/0xb0
>>> [   24.183368]  ___sys_sendmsg+0x86/0xe0
>>> [   24.183372]  ? addrconf_sysctl_forward+0xf3/0x270
>>> [   24.183378]  ? _copy_from_iter+0x8b/0x570
>>> [   24.183384]  ? __pfx_addrconf_sysctl_forward+0x10/0x10
>>> [   24.183388]  ? _raw_spin_unlock+0x19/0x50
>>> [   24.183392]  ? proc_sys_call_handler+0xf3/0x2f0
>>> [   24.183397]  ? trace_hardirqs_on+0x29/0x90
>>> [   24.183401]  ? __fdget+0xc2/0xf0
>>> [   24.183405]  __sys_sendmsg+0x5b/0xc0
>>> [   24.183410]  ? syscall_trace_enter+0x110/0x1b0
>>> [   24.183416]  do_syscall_64+0x64/0x150
>>> [   24.183423]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
>>>
>>> I have bisected the error to this commit. Reverting it caused no new or
>>> perceivable issues on both the MacBook and a Zen4-based laptop.
>>
>> [...]
>>
>>>> Ohh, and when you say "causing peripherals such as the wireless card to
>>>> misbehave" what exactly do you mean?
>>>
>>> When the kernel throws rcu stall messages, the wireless card on the
>>> MacBook may fail to discover and/or connect to wireless networks - not a
>>> consistent behaviour but I suppose that something in the kernel got stuck.
>>
>> See the ticket for more details and dmesg logs; the problem still
>> happens with 6.12-rc. The reporter is CCed.
>>
>> Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
>> --
>> Everything you wanna know about Linux kernel regression tracking:
>> https://linux-regtracking.leemhuis.info/about/#tldr
>> If I did something stupid, please tell me, as explained on that page.
>>
>> P.S.: let me use this mail to also add the report to the list of tracked
>> regressions to ensure it's doesn't fall through the cracks:
>>
>> #regzbot introduced: 55d4669ef1b76823083caecfab12a8bd2ccdcf64
>> #regzbot from: Mingcong Bai <jeffbai@...c.io>
>> #regzbot duplicate: https://bugzilla.kernel.org/show_bug.cgi?id=219390
>> #regzbot title: rcu: wifi problems since tg3 started throwing rcu stall
>> warnings
>> #regzbot ignore-activity
>>
> 
> 

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