Re: [Regression] wifi problems since tg3 started throwing rcu stall warnings

[Mingcong Bai <jeffbai@aosc.io>]

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Hi Frederic,

<snip>

> Sorry for the lag, I still don't understand how this specific commit
> can produce this issue. Can you please retry with and without this 
> commit
> reverted?

Just tested v6.12-rc6 with and without the revert. Without the revert, 
the touchpad and the wireless adapter both stopped working, whereas with 
the revert, both devices functions as normal.

I have attached the dmesg for both kernels below. Unlike the log we got 
last time, there is no direct reference to tg3 any more, but the NMI 
backtrace still pointed to NetworkManager and net/netlink-related 
functions (perhaps a debug kernel would be more helpful?). Here's a 
snippet:

[   10.337720] rcu: INFO: rcu_preempt detected expedited stalls on 
CPUs/tasks: { P683 } 21 jiffies s: 781 root: 0x0/T
[   10.339168] rcu: blocking rcu_node structures (internal RCU debug):
[   10.591480] loop0: detected capacity change from 0 to 8
[   11.777733] rcu: INFO: rcu_preempt detected expedited stalls on 
CPUs/tasks: { 3-.... } 21 jiffies s: 1077 root: 0x8/.
[   11.779210] rcu: blocking rcu_node structures (internal RCU debug):
[   11.780630] Sending NMI from CPU 1 to CPUs 3:
[   11.780659] NMI backtrace for cpu 3
[   11.780663] CPU: 3 UID: 0 PID: 1027 Comm: NetworkManager Not tainted 
6.12.0-aosc-main #1
[   11.780667] Hardware name: Apple Inc. MacBookPro6,2/Mac-F22586C8, 
BIOS    MBP61.88Z.005D.B00.1804100943 04/10/18
[   11.780670] RIP: 0010:0xffffffffc0482051
[   11.780679] 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
[   11.780682] RSP: 0018:ffffb39a8131f5e8 EFLAGS: 00000082
[   11.780685] RAX: 0000000000000000 RBX: ffffa0f4bbd6aa40 RCX: 
0000000000000000
[   11.780687] RDX: 0000000000000000 RSI: ffffb39a804b007c RDI: 
ffffa0f4bbd6aa40
[   11.780689] RBP: 0000000000000b50 R08: 0000000000000000 R09: 
0000000000000000
[   11.780690] R10: 0000000000000000 R11: 0000000000000000 R12: 
0000000000000216
[   11.780692] R13: ffffb39a8131f624 R14: ffffa0f4bbd6aa48 R15: 
ffffa0f4bbd6ab80
[   11.780694] FS:  00007fd9da58d140(0000) GS:ffffa0f5c7d80000(0000) 
knlGS:0000000000000000
[   11.780696] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   11.780698] CR2: 00007fbbd4b681b0 CR3: 0000000104986000 CR4: 
00000000000006f0
[   11.780700] Call Trace:
[   11.780706]  <NMI>
[   11.780710]  ? nmi_cpu_backtrace+0xbf/0x140
[   11.780719]  ? nmi_cpu_backtrace_handler+0x11/0x20
[   11.780725]  ? nmi_handle+0x61/0x160
[   11.780731]  ? default_do_nmi+0x42/0x110
[   11.780736]  ? exc_nmi+0x1bd/0x290
[   11.780740]  ? end_repeat_nmi+0xf/0x53
[   11.780748]  ? 0xffffffffc0482051
[   11.780752]  ? 0xffffffffc0482051
[   11.780754]  ? 0xffffffffc0482051
[   11.780756]  </NMI>
[   11.780757]  <TASK>
[   11.780758]  0xffffffffc0486508
[   11.780762]  ? 0xffffffffc0482010
[   11.780764]  0xffffffffc048e5b6
[   11.780767]  0xffffffffc04907b8
[   11.780770]  0xffffffffc049c01f
[   11.780773]  ? _raw_spin_unlock_irqrestore+0x25/0x70
[   11.780777]  ? 0xffffffffc048e5b6
[   11.780779]  0xffffffffc04a0a53
[   11.780782]  ? delay_tsc+0x89/0xf0
[   11.780786]  ? preempt_count_sub+0x51/0x60
[   11.780792]  0xffffffffc04a0f5b
[   11.780795]  __dev_open+0x103/0x1c0
[   11.780803]  __dev_change_flags+0x1bd/0x230
[   11.780806]  ? rtnl_getlink+0x364/0x400
[   11.780811]  dev_change_flags+0x26/0x70
[   11.780815]  do_setlink+0xe19/0x11f0
[   11.780820]  ? __nla_validate_parse+0x61/0xd40
[   11.780826]  __rtnl_newlink+0x5e7/0x990
[   11.780831]  ? kmem_cache_alloc_node_noprof+0x11d/0x350
[   11.780835]  ? __kmalloc_cache_noprof+0x10c/0x330
[   11.780839]  rtnl_newlink+0x47/0x70
[   11.780842]  rtnetlink_rcv_msg+0x152/0x400
[   11.780846]  ? __netlink_sendskb+0x68/0x90
[   11.780851]  ? netlink_unicast+0x23b/0x290
[   11.780856]  ? __pfx_rtnetlink_rcv_msg+0x10/0x10
[   11.780859]  netlink_rcv_skb+0x5b/0x110
[   11.780865]  netlink_unicast+0x1a6/0x290
[   11.780870]  netlink_sendmsg+0x222/0x4b0
[   11.780873]  ? proc_get_long.constprop.0+0x116/0x210
[   11.780879]  ____sys_sendmsg+0x379/0x3b0
[   11.780885]  ? copy_msghdr_from_user+0x6d/0xb0
[   11.780891]  ___sys_sendmsg+0x86/0xe0
[   11.780897]  ? addrconf_sysctl_forward+0xf3/0x270
[   11.780902]  ? _copy_from_iter+0x8b/0x6b0
[   11.780906]  ? __pfx_addrconf_sysctl_forward+0x10/0x10
[   11.780911]  ? _raw_spin_unlock+0x19/0x50
[   11.780914]  ? proc_sys_call_handler+0xf0/0x2f0
[   11.780922]  ? trace_hardirqs_on+0x29/0x90
[   11.780927]  ? mod_objcg_state+0x102/0x300
[   11.780932]  ? fdget+0xd2/0x100
[   11.780938]  __sys_sendmsg+0x5b/0xc0
[   11.780944]  ? syscall_trace_enter+0x110/0x1b0
[   11.780951]  do_syscall_64+0x64/0x150
[   11.780957]  entry_SYSCALL_64_after_hwframe+0x76/0x7e

Also looping our distro kernel maintainer here.

Best Regards,
Mingcong Bai

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