BUG: iproute2 4.14.1 tc class add come to kernel-panic

BUG: iproute2 4.14.1 tc class add come to kernel-panic

[Roland Franke]

Starting with Kernel 4.14.1 (x86_64) I found the following problem:
When I made the following commands:

tc qdisc add dev eth0 root handle 20: htb default 4 r2q 1
tc class add dev eth0 parent 20: classid 20:7 htb rate 10000kbit
tc qdisc add dev eth0 parent 20:7 sfq perturb 10
tc class add dev eth0 parent 20:7 classid 20:1 htb rate 200kbit ceil 
10000kbit prio 0

I become an Kernel-panic with the following output:
kern.err kernel: BUG: scheduling while atomic: tc/1036/0x00000200

The identical message come, when i try the kernel till 4.14.15.

When i have tested the same with one of the kernels from the 4.13 series,
i had no problem.Will this be solved in the kernel-series 4.14 or will this 
only with the
coming series 4.15 be made?

Kernel 4.15 is not be tested till now.

Best regards,
Roland Franke 

Re: BUG: iproute2 4.14.1 tc class add come to kernel-panic

[Eric Dumazet]

On Mon, 2018-01-29 at 15:51 +0100, Roland Franke wrote:
> Starting with Kernel 4.14.1 (x86_64) I found the following problem:
> When I made the following commands:
> 
> tc qdisc add dev eth0 root handle 20: htb default 4 r2q 1
> tc class add dev eth0 parent 20: classid 20:7 htb rate 10000kbit
> tc qdisc add dev eth0 parent 20:7 sfq perturb 10
> tc class add dev eth0 parent 20:7 classid 20:1 htb rate 200kbit ceil 
> 10000kbit prio 0
> 
> I become an Kernel-panic with the following output:
> kern.err kernel: BUG: scheduling while atomic: tc/1036/0x00000200
> 
> The identical message come, when i try the kernel till 4.14.15.
> 
> When i have tested the same with one of the kernels from the 4.13 series,
> i had no problem.Will this be solved in the kernel-series 4.14 or will this 
> only with the
> coming series 4.15 be made?
> 
> Kernel 4.15 is not be tested till now.
> 
> Best regards,
> Roland Franke 
> 

Hi Roland

Would you have a stack trace to share with us ?

Thanks !

Re: iproute2 4.14.1 tc class add come to kernel-panic

[Roland Franke]

Hello,

> To: Roland Franke ; netdev@vger.kernel.org 
> Subject: Re: BUG: iproute2 4.14.1 tc class add come to kernel-panic 
>> 
>> tc qdisc add dev eth0 root handle 20: htb default 4 r2q 1
>> tc class add dev eth0 parent 20: classid 20:7 htb rate 10000kbit
>> tc qdisc add dev eth0 parent 20:7 sfq perturb 10
>> tc class add dev eth0 parent 20:7 classid 20:1 htb rate 200kbit ceil 
>> 10000kbit prio 0
>> 
>> I become an Kernel-panic with the following output:
>> kern.err kernel: BUG: scheduling while atomic: tc/1036/0x00000200
> 

> Would you have a stack trace to share with us ?

As i will be an absolute newby here, i will not know how to 
get the stack trace out.
When i will get some information how to get this, i can try to 
give you this information.
But by my last tests i made the first 3 commands on an console
and had no error. Only by typing the last line i will get the error and
here i get actally only the "kern.err kernel: BUG: ....." message.

Roland

Re: iproute2 4.14.1 tc class add come to kernel-panic

[Stephen Hemminger]

On Mon, 29 Jan 2018 16:18:07 +0100
"Roland Franke" <fli4l@franke-prem.de> wrote:

> Hello,
> 
> > To: Roland Franke ; netdev@vger.kernel.org 
> > Subject: Re: BUG: iproute2 4.14.1 tc class add come to kernel-panic   
> >> 
> >> tc qdisc add dev eth0 root handle 20: htb default 4 r2q 1
> >> tc class add dev eth0 parent 20: classid 20:7 htb rate 10000kbit
> >> tc qdisc add dev eth0 parent 20:7 sfq perturb 10
> >> tc class add dev eth0 parent 20:7 classid 20:1 htb rate 200kbit ceil 
> >> 10000kbit prio 0
> >> 
> >> I become an Kernel-panic with the following output:
> >> kern.err kernel: BUG: scheduling while atomic: tc/1036/0x00000200  
> >   
> 
> > Would you have a stack trace to share with us ?  
> 
> As i will be an absolute newby here, i will not know how to 
> get the stack trace out.
> When i will get some information how to get this, i can try to 
> give you this information.
> But by my last tests i made the first 3 commands on an console
> and had no error. Only by typing the last line i will get the error and
> here i get actally only the "kern.err kernel: BUG: ....." message.
> 
> Roland

It generates this with lockdep (on 4.15)

[  151.355076] HTB: quantum of class 200007 is big. Consider r2q change.
[  151.371495] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:747
[  151.371815] in_atomic(): 1, irqs_disabled(): 0, pid: 1135, name: tc
[  151.371875] 2 locks held by tc/1135:
[  151.371878]  #0:  (rtnl_mutex){+.+.}, at: [<ffffffff98826e5b>] rtnetlink_rcv_msg+0x23b/0x5f0
[  151.371899]  #1:  (&qdisc_tx_lock){+...}, at: [<ffffffffc07a5f0f>] htb_change_class+0x55f/0x880 [sch_htb]
[  151.371918] CPU: 2 PID: 1135 Comm: tc Not tainted 4.14.15 #2
[  151.371921] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[  151.371924] Call Trace:
[  151.371934]  dump_stack+0x7c/0xbe
[  151.371944]  ___might_sleep+0x21e/0x250
[  151.371953]  __mutex_lock+0x59/0x9a0
[  151.371960]  ? lock_acquire+0xec/0x1e0
[  151.371973]  ? __raw_spin_lock_init+0x1c/0x50
[  151.371990]  ? _rcu_barrier+0x2f/0x170
[  151.371995]  ? __lockdep_init_map+0x5c/0x1d0
[  151.371998]  _rcu_barrier+0x2f/0x170
[  151.372006]  tcf_block_put+0x7f/0xa0
[  151.372013]  sfq_destroy+0x15/0x50 [sch_sfq]
[  151.372021]  qdisc_destroy+0x6c/0xe0
[  151.372028]  htb_change_class+0x704/0x880 [sch_htb]
[  151.372050]  tc_ctl_tclass+0x193/0x3c0
[  151.372075]  rtnetlink_rcv_msg+0x270/0x5f0
[  151.372088]  ? rtnetlink_put_metrics+0x1c0/0x1c0
[  151.372096]  netlink_rcv_skb+0xde/0x110
[  151.372109]  netlink_unicast+0x1e4/0x310
[  151.372118]  netlink_sendmsg+0x2dc/0x3c0
[  151.372136]  sock_sendmsg+0x30/0x40
[  151.372142]  ___sys_sendmsg+0x2b9/0x2d0
[  151.372171]  ? __handle_mm_fault+0x7f8/0x1120
[  151.372189]  ? __do_page_fault+0x2a5/0x530
[  151.372200]  ? __sys_sendmsg+0x51/0x90
[  151.372205]  __sys_sendmsg+0x51/0x90
[  151.372225]  entry_SYSCALL_64_fastpath+0x29/0xa0
[  151.372230] RIP: 0033:0x7f7049397490
[  151.372233] RSP: 002b:00007ffd0c432f48 EFLAGS: 00000246
[  151.372445] BUG: scheduling while atomic: tc/1135/0x00000202
[  151.372524] 3 locks held by tc/1135:
[  151.372527]  #0:  (rtnl_mutex){+.+.}, at: [<ffffffff98826e5b>] rtnetlink_rcv_msg+0x23b/0x5f0
[  151.372544]  #1:  (&qdisc_tx_lock){+...}, at: [<ffffffffc07a5f0f>] htb_change_class+0x55f/0x880 [sch_htb]
[  151.372560]  #2:  (rcu_sched_state.barrier_mutex){+.+.}, at: [<ffffffff9810bbbf>] _rcu_barrier+0x2f/0x170
[  151.372575] Modules linked in: sch_sfq sch_htb ppdev input_leds serio_raw joydev parport_pc parport i2c_piix4 mac_hid ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi autofs4 btrfs zstd_decompress zstd_compress xxhash raid10 raid456 libcrc32c async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq raid1 raid0 multipath linear qxl drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm drm crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel aes_x86_64 crypto_simd cryptd glue_helper psmouse floppy pata_acpi hid_generic usbhid hid
[  151.372748] CPU: 2 PID: 1135 Comm: tc Tainted: G        W       4.14.15 #2
[  151.372751] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[  151.372753] Call Trace:
[  151.372759]  dump_stack+0x7c/0xbe
[  151.372767]  __schedule_bug+0x62/0x90
[  151.372772]  __schedule+0x7d9/0xb80
[  151.372788]  schedule+0x39/0x90
[  151.372793]  schedule_timeout+0x24d/0x5c0
[  151.372813]  ? mark_held_locks+0x71/0xa0
[  151.372825]  ? wait_for_completion+0x12e/0x1a0
[  151.372829]  wait_for_completion+0x12e/0x1a0
[  151.372835]  ? wake_up_q+0x60/0x60
[  151.372846]  _rcu_barrier+0x11a/0x170
[  151.372853]  tcf_block_put+0x7f/0xa0
[  151.372860]  sfq_destroy+0x15/0x50 [sch_sfq]
[  151.372866]  qdisc_destroy+0x6c/0xe0
[  151.372872]  htb_change_class+0x704/0x880 [sch_htb]
[  151.372894]  tc_ctl_tclass+0x193/0x3c0
[  151.372918]  rtnetlink_rcv_msg+0x270/0x5f0
[  151.372932]  ? rtnetlink_put_metrics+0x1c0/0x1c0
[  151.372940]  netlink_rcv_skb+0xde/0x110
[  151.372952]  netlink_unicast+0x1e4/0x310
[  151.372961]  netlink_sendmsg+0x2dc/0x3c0
[  151.372977]  sock_sendmsg+0x30/0x40
[  151.372983]  ___sys_sendmsg+0x2b9/0x2d0
[  151.373010]  ? __handle_mm_fault+0x7f8/0x1120
[  151.373026]  ? __do_page_fault+0x2a5/0x530
[  151.373037]  ? __sys_sendmsg+0x51/0x90
[  151.373042]  __sys_sendmsg+0x51/0x90
[  151.373061]  entry_SYSCALL_64_fastpath+0x29/0xa0
[  151.373065] RIP: 0033:0x7f7049397490
[  151.373068] RSP: 002b:00007ffd0c432f48 EFLAGS: 00000246
[  151.373306] NOHZ: local_softirq_pending 202
[  151.400331] ------------[ cut here ]------------
[  151.400342] WARNING: CPU: 2 PID: 1135 at net/core/skbuff.c:615 skb_release_head_state+0x4b/0x50
[  151.400345] Modules linked in: sch_sfq sch_htb ppdev input_leds serio_raw joydev parport_pc parport i2c_piix4 mac_hid ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi autofs4 btrfs zstd_decompress zstd_compress xxhash raid10 raid456 libcrc32c async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq raid1 raid0 multipath linear qxl drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm drm crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel aes_x86_64 crypto_simd cryptd glue_helper psmouse floppy pata_acpi hid_generic usbhid hid
[  151.400521] CPU: 2 PID: 1135 Comm: tc Tainted: G        W       4.14.15 #2
[  151.400524] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[  151.400527] task: ffff980e7b050000 task.stack: ffffa3ca00578000
[  151.400532] RIP: 0010:skb_release_head_state+0x4b/0x50
[  151.400536] RSP: 0018:ffffa3ca0057bc38 EFLAGS: 00010206
[  151.400543] RAX: ffffffff9884c9a0 RBX: ffff980e7b18c800 RCX: 0000000000000002
[  151.400546] RDX: 00000000000f0000 RSI: 00000000ffffffff RDI: 0000000000000000
[  151.400550] RBP: ffff980e72d9f800 R08: 0000000000000004 R09: 0000000000000000
[  151.400553] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000868
[  151.400556] R13: ffff980e7b18c800 R14: 0000000000000000 R15: 0000000000000000
[  151.400560] FS:  00007f7049d82700(0000) GS:ffff980e7e200000(0000) knlGS:0000000000000000
[  151.400564] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  151.400567] CR2: 00007fb14b0f74a0 CR3: 000000003b142004 CR4: 00000000003606e0
[  151.400574] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  151.400578] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  151.400581] Call Trace:
[  151.400589]  skb_release_all+0xe/0x30
[  151.400594]  consume_skb+0x43/0x140
[  151.400603]  netlink_unicast+0x1ec/0x310
[  151.400613]  netlink_sendmsg+0x2dc/0x3c0
[  151.400630]  sock_sendmsg+0x30/0x40
[  151.400637]  ___sys_sendmsg+0x2b9/0x2d0
[  151.400667]  ? __handle_mm_fault+0x7f8/0x1120
[  151.400685]  ? __do_page_fault+0x2a5/0x530
[  151.400697]  ? __sys_sendmsg+0x51/0x90
[  151.400702]  __sys_sendmsg+0x51/0x90
[  151.400724]  entry_SYSCALL_64_fastpath+0x29/0xa0
[  151.400729] RIP: 0033:0x7f7049397490
[  151.400732] RSP: 002b:00007ffd0c432f48 EFLAGS: 00000246
[  151.400755] Code: 48 8b 43 60 48 85 c0 74 20 65 8b 15 b0 c2 81 67 81 e2 00 00 0f 00 75 13 48 89 df 5b ff e0 48 83 e7 fe e8 a9 27 02 00 eb cf 5b c3 <0f> ff eb e9 90 0f 1f 44 00 00 53 48 89 fb e8 a2 ff ff ff 48 83 
[  151.400935] ---[ end trace a2dc1d508339e762 ]---
[  151.400954] show_signal_msg: 5 callbacks suppressed
[  151.400957] tc[1135]: segfault at 7ffd0c434000 ip 00007f7049401af8 sp 00007ffd0c432f48 error 6
[  151.401033] BUG: scheduling while atomic: tc/1135/0x7ffffe00
[  151.401104] no locks held by tc/1135.
[  151.401107] Modules linked in: sch_sfq sch_htb ppdev input_leds serio_raw joydev parport_pc parport i2c_piix4 mac_hid ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi autofs4 btrfs zstd_decompress zstd_compress xxhash raid10 raid456 libcrc32c async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq raid1 raid0 multipath linear qxl drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm drm crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel aes_x86_64 crypto_simd cryptd glue_helper psmouse floppy pata_acpi hid_generic usbhid hid
[  151.401277] CPU: 2 PID: 1135 Comm: tc Tainted: G        W       4.14.15 #2
[  151.401281] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[  151.401284] Call Trace:
[  151.401291]  dump_stack+0x7c/0xbe
[  151.401300]  __schedule_bug+0x62/0x90
[  151.401306]  __schedule+0x7d9/0xb80
[  151.401323]  schedule+0x39/0x90
[  151.401329]  schedule_timeout+0x24d/0x5c0
[  151.401334]  ? try_to_wake_up+0x55/0x550
[  151.401351]  ? wait_for_completion+0x126/0x1a0
[  151.401366]  ? wait_for_completion+0x12e/0x1a0
[  151.401371]  wait_for_completion+0x12e/0x1a0
[  151.401377]  ? wake_up_q+0x60/0x60
[  151.401389]  call_usermodehelper_exec+0x143/0x170
[  151.401402]  ? wait_for_completion+0x49/0x1a0
[  151.401415]  do_coredump+0xb8a/0x10e0
[  151.401466]  get_signal+0x3d0/0x8f0
[  151.401488]  do_signal+0x36/0x700
[  151.401493]  ? force_sig_info+0xca/0xe0
[  151.401504]  ? force_sig_info_fault+0x97/0xf0
[  151.401519]  ? __bad_area_nosemaphore+0x168/0x1a0
[  151.401537]  exit_to_usermode_loop+0x80/0xc0
[  151.401543]  ? async_page_fault+0x36/0x60
[  151.401550]  prepare_exit_to_usermode+0x7a/0x90
[  151.401557]  retint_user+0x8/0x18
[  151.401562] RIP: 0033:0x7f7049401af8
[  151.401565] RSP: 002b:00007ffd0c432f48 EFLAGS: 00010207
[  151.401571] RAX: 0000000000000000 RBX: 000000000064cb00 RCX: 0000000000006fd0
[  151.401575] RDX: 0000000000008000 RSI: 00007ffd0c43afd0 RDI: 00007ffd0c434000
[  151.401578] RBP: 000000005a6f436a R08: 0000000000000014 R09: 0000000000000000
[  151.401581] R10: 00000000000005e7 R11: 0000000000000246 R12: 00007ffd0c432f90
[  151.401584] R13: 00007ffd0c432fd0 R14: 0000000000655aa0 R15: 0000000000000000

[  168.036082] ========================================================
[  168.037902] WARNING: possible irq lock inversion dependency detected
[  168.039397] 4.14.15 #2 Tainted: G        W      
[  168.040574] --------------------------------------------------------
[  168.041051] swapper/3/0 just changed the state of lock:
[  168.041520]  (&qdisc_tx_lock){+.-.}, at: [<ffffffff98811e2a>] __dev_queue_xmit+0x24a/0x9a0
[  168.042009] but this lock took another, SOFTIRQ-unsafe lock in the past:
[  168.042486]  (rcu_sched_state.barrier_mutex){+.+.}
[  168.042488] 
               
               and interrupts could create inverse lock ordering between them.

[  168.044723] 
               other info that might help us debug this:
[  168.045509]  Possible interrupt unsafe locking scenario:

[  168.046288]        CPU0                    CPU1
[  168.046649]        ----                    ----
[  168.047009]   lock(rcu_sched_state.barrier_mutex);
[  168.047372]                                local_irq_disable();
[  168.047742]                                lock(&qdisc_tx_lock);
[  168.048112]                                lock(rcu_sched_state.barrier_mutex);
[  168.048504]   <Interrupt>
[  168.048871]     lock(&qdisc_tx_lock);
[  168.049240] 
                *** DEADLOCK ***

[  168.050329] 4 locks held by swapper/3/0:
[  168.050693]  #0:  (rcu_read_lock){....}, at: [<ffffffff9881355a>] netif_receive_skb_internal+0x2a/0x360
[  168.051082]  #1:  (rcu_read_lock){....}, at: [<ffffffff9885e836>] ip_local_deliver_finish+0x26/0x1f0
[  168.051472]  #2:  (rcu_read_lock_bh){....}, at: [<ffffffff9886389c>] ip_finish_output2+0xac/0x650
[  168.051868]  #3:  (rcu_read_lock_bh){....}, at: [<ffffffff98811c3e>] __dev_queue_xmit+0x5e/0x9a0
[  168.052266] 
               the shortest dependencies between 2nd lock and 1st lock:
[  168.053089]  -> (rcu_sched_state.barrier_mutex){+.+.} ops: 3 {
[  168.053504]     HARDIRQ-ON-W at:
[  168.053900]                       lock_acquire+0xec/0x1e0
[  168.054301]                       __mutex_lock+0x92/0x9a0
[  168.054698]                       _rcu_barrier+0x2f/0x170
[  168.055094]                       slab_caches_to_rcu_destroy_workfn+0x95/0xe0
[  168.055522]                       process_one_work+0x204/0x650
[  168.055922]                       worker_thread+0x4d/0x3e0
[  168.056316]                       kthread+0x10a/0x140
[  168.056717]                       ret_from_fork+0x3a/0x50
[  168.057107]     SOFTIRQ-ON-W at:
[  168.057494]                       lock_acquire+0xec/0x1e0
[  168.057886]                       __mutex_lock+0x92/0x9a0
[  168.058267]                       _rcu_barrier+0x2f/0x170
[  168.058641]                       slab_caches_to_rcu_destroy_workfn+0x95/0xe0
[  168.059016]                       process_one_work+0x204/0x650
[  168.059386]                       worker_thread+0x4d/0x3e0
[  168.059751]                       kthread+0x10a/0x140
[  168.060109]                       ret_from_fork+0x3a/0x50
[  168.060468]     INITIAL USE at:
[  168.060808]                      lock_acquire+0xec/0x1e0
[  168.061147]                      __mutex_lock+0x92/0x9a0
[  168.061484]                      _rcu_barrier+0x2f/0x170
[  168.061825]                      slab_caches_to_rcu_destroy_workfn+0x95/0xe0
[  168.062166]                      process_one_work+0x204/0x650
[  168.062502]                      worker_thread+0x4d/0x3e0
[  168.062843]                      kthread+0x10a/0x140
[  168.063180]                      ret_from_fork+0x3a/0x50
[  168.063514]   }
[  168.063857]   ... key      at: [<ffffffff992798b0>] rcu_sched_state+0x8530/0x8800
[  168.064200]   ... acquired at:
[  168.064554]    __mutex_lock+0x92/0x9a0
[  168.064897]    _rcu_barrier+0x2f/0x170
[  168.065236]    tcf_block_put+0x7f/0xa0
[  168.065599]    sfq_destroy+0x15/0x50 [sch_sfq]
[  168.065940]    qdisc_destroy+0x6c/0xe0
[  168.066277]    htb_change_class+0x704/0x880 [sch_htb]
[  168.066618]    tc_ctl_tclass+0x193/0x3c0
[  168.066960]    rtnetlink_rcv_msg+0x270/0x5f0
[  168.067306]    netlink_rcv_skb+0xde/0x110
[  168.067653]    netlink_unicast+0x1e4/0x310
[  168.067999]    netlink_sendmsg+0x2dc/0x3c0
[  168.068332]    sock_sendmsg+0x30/0x40
[  168.068713]    ___sys_sendmsg+0x2b9/0x2d0
[  168.069036]    __sys_sendmsg+0x51/0x90
[  168.069357]    entry_SYSCALL_64_fastpath+0x29/0xa0

[  168.069974] -> (&qdisc_tx_lock){+.-.} ops: 5 {
[  168.070283]    HARDIRQ-ON-W at:
[  168.070587]                     lock_acquire+0xec/0x1e0
[  168.070901]                     _raw_spin_lock_bh+0x38/0x70
[  168.071212]                     htb_change_class+0x55f/0x880 [sch_htb]
[  168.071526]                     tc_ctl_tclass+0x193/0x3c0
[  168.071838]                     rtnetlink_rcv_msg+0x270/0x5f0
[  168.072148]                     netlink_rcv_skb+0xde/0x110
[  168.072466]                     netlink_unicast+0x1e4/0x310
[  168.072774]                     netlink_sendmsg+0x2dc/0x3c0
[  168.073080]                     sock_sendmsg+0x30/0x40
[  168.073384]                     ___sys_sendmsg+0x2b9/0x2d0
[  168.073703]                     __sys_sendmsg+0x51/0x90
[  168.074005]                     entry_SYSCALL_64_fastpath+0x29/0xa0
[  168.074312]    IN-SOFTIRQ-W at:
[  168.074615]                     lock_acquire+0xec/0x1e0
[  168.074948]                     _raw_spin_lock+0x30/0x70
[  168.075260]                     __dev_queue_xmit+0x24a/0x9a0
[  168.075567]                     ip_finish_output2+0x4c6/0x650
[  168.075877]                     ip_output+0x7c/0x250
[  168.076183]                     tcp_v4_send_synack+0x8e/0x120
[  168.076497]                     tcp_conn_request+0xaf4/0xc80
[  168.076804]                     tcp_rcv_state_process+0x233/0xf30
[  168.077114]                     tcp_v4_do_rcv+0xae/0x1c0
[  168.077419]                     tcp_v4_rcv+0xa2e/0xa80
[  168.077720]                     ip_local_deliver_finish+0x97/0x1f0
[  168.078024]                     ip_local_deliver+0x71/0x210
[  168.078329]                     ip_rcv+0x271/0x4c0
[  168.078631]                     __netif_receive_skb_core+0x79c/0xd20
[  168.078937]                     netif_receive_skb_internal+0x1a7/0x360
[  168.079241]                     napi_gro_receive+0x137/0x1b0
[  168.079539]                     receive_buf+0x444/0x1730
[  168.079837]                     virtnet_poll+0x119/0x290
[  168.080136]                     net_rx_action+0x1fd/0x410
[  168.080444]                     __do_softirq+0xc8/0x49a
[  168.080743]                     irq_exit+0xc1/0xd0
[  168.081039]                     do_IRQ+0x60/0x110
[  168.081333]                     ret_from_intr+0x0/0x22
[  168.081624]                     native_safe_halt+0x2/0x10
[  168.081917]                     default_idle+0x1d/0x1a0
[  168.082209]                     do_idle+0x170/0x200
[  168.082501]                     cpu_startup_entry+0x6f/0x80
[  168.082797]                     start_secondary+0x197/0x1f0
[  168.083093]                     secondary_startup_64+0xa5/0xb0
[  168.083404]    INITIAL USE at:
[  168.083697]                    lock_acquire+0xec/0x1e0
[  168.083995]                    _raw_spin_lock_bh+0x38/0x70
[  168.084293]                    htb_change_class+0x55f/0x880 [sch_htb]
[  168.084614]                    tc_ctl_tclass+0x193/0x3c0
[  168.084922]                    rtnetlink_rcv_msg+0x270/0x5f0
[  168.085218]                    netlink_rcv_skb+0xde/0x110
[  168.085514]                    netlink_unicast+0x1e4/0x310
[  168.085807]                    netlink_sendmsg+0x2dc/0x3c0
[  168.086096]                    sock_sendmsg+0x30/0x40
[  168.086384]                    ___sys_sendmsg+0x2b9/0x2d0
[  168.086673]                    __sys_sendmsg+0x51/0x90
[  168.086963]                    entry_SYSCALL_64_fastpath+0x29/0xa0
[  168.087256]  }
[  168.087544]  ... key      at: [<ffffffff9a7cc448>] qdisc_tx_lock+0x0/0x8
[  168.087845]  ... acquired at:
[  168.088144]    mark_lock+0x30a/0x5c0
[  168.088448]    __lock_acquire+0x3a5/0x1510
[  168.088743]    lock_acquire+0xec/0x1e0
[  168.089035]    _raw_spin_lock+0x30/0x70
[  168.089328]    __dev_queue_xmit+0x24a/0x9a0
[  168.089621]    ip_finish_output2+0x4c6/0x650
[  168.089915]    ip_output+0x7c/0x250
[  168.090207]    tcp_v4_send_synack+0x8e/0x120
[  168.090500]    tcp_conn_request+0xaf4/0xc80
[  168.090794]    tcp_rcv_state_process+0x233/0xf30
[  168.091089]    tcp_v4_do_rcv+0xae/0x1c0
[  168.091382]    tcp_v4_rcv+0xa2e/0xa80
[  168.091675]    ip_local_deliver_finish+0x97/0x1f0
[  168.091971]    ip_local_deliver+0x71/0x210
[  168.092265]    ip_rcv+0x271/0x4c0
[  168.092561]    __netif_receive_skb_core+0x79c/0xd20
[  168.092857]    netif_receive_skb_internal+0x1a7/0x360
[  168.093154]    napi_gro_receive+0x137/0x1b0
[  168.093448]    receive_buf+0x444/0x1730
[  168.093758]    virtnet_poll+0x119/0x290
[  168.094050]    net_rx_action+0x1fd/0x410
[  168.094355]    __do_softirq+0xc8/0x49a
[  168.094647]    irq_exit+0xc1/0xd0
[  168.094937]    do_IRQ+0x60/0x110
[  168.095227]    ret_from_intr+0x0/0x22
[  168.095518]    native_safe_halt+0x2/0x10
[  168.095809]    default_idle+0x1d/0x1a0
[  168.096099]    do_idle+0x170/0x200
[  168.096395]    cpu_startup_entry+0x6f/0x80
[  168.096687]    start_secondary+0x197/0x1f0
[  168.096978]    secondary_startup_64+0xa5/0xb0

[  168.097552] 
               stack backtrace:
[  168.098105] CPU: 3 PID: 0 Comm: swapper/3 Tainted: G        W       4.14.15 #2
[  168.098393] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[  168.098690] Call Trace:
[  168.098986]  <IRQ>
[  168.099278]  dump_stack+0x7c/0xbe
[  168.099574]  print_irq_inversion_bug.part.43+0x198/0x1a3
[  168.099877]  check_usage_forwards+0x17a/0x180
[  168.100182]  ? __save_stack_trace+0x82/0x100
[  168.100493]  ? secondary_startup_64+0xa5/0xb0
[  168.100799]  ? check_usage_backwards+0x180/0x180
[  168.101106]  ? mark_lock+0x30a/0x5c0
[  168.101410]  mark_lock+0x30a/0x5c0
[  168.101709]  __lock_acquire+0x3a5/0x1510
[  168.102005]  ? __lock_acquire+0xc21/0x1510
[  168.102303]  ? lock_acquire+0xec/0x1e0
[  168.102598]  lock_acquire+0xec/0x1e0
[  168.102893]  ? __dev_queue_xmit+0x24a/0x9a0
[  168.103191]  _raw_spin_lock+0x30/0x70
[  168.103488]  ? __dev_queue_xmit+0x24a/0x9a0
[  168.103803]  __dev_queue_xmit+0x24a/0x9a0
[  168.104124]  ip_finish_output2+0x4c6/0x650
[  168.104437]  ? ip_output+0x7c/0x250
[  168.104733]  ip_output+0x7c/0x250
[  168.105028]  ? tcp_make_synack+0x38b/0x4b0
[  168.105325]  tcp_v4_send_synack+0x8e/0x120
[  168.105623]  ? _raw_spin_unlock+0x24/0x30
[  168.105920]  ? inet_ehash_insert+0xfa/0x170
[  168.106218]  tcp_conn_request+0xaf4/0xc80
[  168.106519]  ? tcp_rcv_state_process+0x233/0xf30
[  168.106818]  tcp_rcv_state_process+0x233/0xf30
[  168.107119]  ? tcp_v4_do_rcv+0xae/0x1c0
[  168.107416]  tcp_v4_do_rcv+0xae/0x1c0
[  168.107713]  tcp_v4_rcv+0xa2e/0xa80
[  168.108010]  ip_local_deliver_finish+0x97/0x1f0
[  168.108310]  ip_local_deliver+0x71/0x210
[  168.108614]  ip_rcv+0x271/0x4c0
[  168.108953]  ? packet_rcv+0x3d/0x3a0
[  168.109261]  __netif_receive_skb_core+0x79c/0xd20
[  168.109564]  ? lock_acquire+0xec/0x1e0
[  168.109867]  ? dev_gro_receive+0x26b/0x5c0
[  168.110172]  ? netif_receive_skb_internal+0x2a/0x360
[  168.110480]  ? netif_receive_skb_internal+0x1a7/0x360
[  168.110892]  ? netif_receive_skb_internal+0x56/0x360
[  168.111197]  netif_receive_skb_internal+0x1a7/0x360
[  168.111503]  napi_gro_receive+0x137/0x1b0
[  168.111806]  receive_buf+0x444/0x1730
[  168.112115]  ? __lock_acquire+0x2e7/0x1510
[  168.112439]  ? vring_unmap_one+0x16/0x70
[  168.112754]  ? detach_buf+0x68/0x110
[  168.113052]  virtnet_poll+0x119/0x290
[  168.113339]  ? __wake_up_common_lock+0x89/0xc0
[  168.113675]  net_rx_action+0x1fd/0x410
[  168.113970]  ? credit_entropy_bits+0x313/0x350
[  168.114262]  __do_softirq+0xc8/0x49a
[  168.114551]  irq_exit+0xc1/0xd0
[  168.114837]  do_IRQ+0x60/0x110
[  168.115121]  common_interrupt+0xa2/0xa2
[  168.115404]  </IRQ>
[  168.115684] RIP: 0010:native_safe_halt+0x2/0x10
[  168.115969] RSP: 0018:ffffa3ca001ffec8 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff2e
[  168.116267] RAX: ffff980e7db91b40 RBX: ffff980e7db91b40 RCX: 0000000000000000
[  168.116578] RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffff980e7db91b40
[  168.116886] RBP: 0000000000000003 R08: 0000000000000001 R09: 0000000000000000
[  168.117194] R10: 0000000000000000 R11: 0000000000000000 R12: ffff980e7db91b40
[  168.117501] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[  168.117811]  default_idle+0x1d/0x1a0
[  168.118116]  do_idle+0x170/0x200
[  168.118419]  cpu_startup_entry+0x6f/0x80
[  168.118725]  start_secondary+0x197/0x1f0
[  168.119029]  secondary_startup_64+0xa5/0xb0

Re: iproute2 4.14.1 tc class add come to kernel-panic

[Cong Wang]

On Mon, Jan 29, 2018 at 8:00 AM, Stephen Hemminger
<stephen@networkplumber.org> wrote:
> On Mon, 29 Jan 2018 16:18:07 +0100
> "Roland Franke" <fli4l@franke-prem.de> wrote:
>
>> Hello,
>>
>> > To: Roland Franke ; netdev@vger.kernel.org
>> > Subject: Re: BUG: iproute2 4.14.1 tc class add come to kernel-panic
>> >>
>> >> tc qdisc add dev eth0 root handle 20: htb default 4 r2q 1
>> >> tc class add dev eth0 parent 20: classid 20:7 htb rate 10000kbit
>> >> tc qdisc add dev eth0 parent 20:7 sfq perturb 10
>> >> tc class add dev eth0 parent 20:7 classid 20:1 htb rate 200kbit ceil
>> >> 10000kbit prio 0
>> >>
>> >> I become an Kernel-panic with the following output:
>> >> kern.err kernel: BUG: scheduling while atomic: tc/1036/0x00000200
>> >
>>
>> > Would you have a stack trace to share with us ?
>>
>> As i will be an absolute newby here, i will not know how to
>> get the stack trace out.
>> When i will get some information how to get this, i can try to
>> give you this information.
>> But by my last tests i made the first 3 commands on an console
>> and had no error. Only by typing the last line i will get the error and
>> here i get actally only the "kern.err kernel: BUG: ....." message.
>>
>> Roland
>
> It generates this with lockdep (on 4.15)
>
> [  151.355076] HTB: quantum of class 200007 is big. Consider r2q change.
> [  151.371495] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:747
> [  151.371815] in_atomic(): 1, irqs_disabled(): 0, pid: 1135, name: tc
> [  151.371875] 2 locks held by tc/1135:
> [  151.371878]  #0:  (rtnl_mutex){+.+.}, at: [<ffffffff98826e5b>] rtnetlink_rcv_msg+0x23b/0x5f0
> [  151.371899]  #1:  (&qdisc_tx_lock){+...}, at: [<ffffffffc07a5f0f>] htb_change_class+0x55f/0x880 [sch_htb]
> [  151.371918] CPU: 2 PID: 1135 Comm: tc Not tainted 4.14.15 #2
> [  151.371921] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
> [  151.371924] Call Trace:
> [  151.371934]  dump_stack+0x7c/0xbe
> [  151.371944]  ___might_sleep+0x21e/0x250
> [  151.371953]  __mutex_lock+0x59/0x9a0
> [  151.371960]  ? lock_acquire+0xec/0x1e0
> [  151.371973]  ? __raw_spin_lock_init+0x1c/0x50
> [  151.371990]  ? _rcu_barrier+0x2f/0x170
> [  151.371995]  ? __lockdep_init_map+0x5c/0x1d0
> [  151.371998]  _rcu_barrier+0x2f/0x170
> [  151.372006]  tcf_block_put+0x7f/0xa0
> [  151.372013]  sfq_destroy+0x15/0x50 [sch_sfq]
> [  151.372021]  qdisc_destroy+0x6c/0xe0
> [  151.372028]  htb_change_class+0x704/0x880 [sch_htb]


We hold qdisc tree spinlock but call rcu_barrier() in
mini_qdisc_pair_swap()...



> [  151.372050]  tc_ctl_tclass+0x193/0x3c0
> [  151.372075]  rtnetlink_rcv_msg+0x270/0x5f0
> [  151.372088]  ? rtnetlink_put_metrics+0x1c0/0x1c0
> [  151.372096]  netlink_rcv_skb+0xde/0x110
> [  151.372109]  netlink_unicast+0x1e4/0x310
> [  151.372118]  netlink_sendmsg+0x2dc/0x3c0
> [  151.372136]  sock_sendmsg+0x30/0x40
> [  151.372142]  ___sys_sendmsg+0x2b9/0x2d0
> [  151.372171]  ? __handle_mm_fault+0x7f8/0x1120
> [  151.372189]  ? __do_page_fault+0x2a5/0x530
> [  151.372200]  ? __sys_sendmsg+0x51/0x90
> [  151.372205]  __sys_sendmsg+0x51/0x90
> [  151.372225]  entry_SYSCALL_64_fastpath+0x29/0xa0
> [  151.372230] RIP: 0033:0x7f7049397490
> [  151.372233] RSP: 002b:00007ffd0c432f48 EFLAGS: 00000246
> [  151.372445] BUG: scheduling while atomic: tc/1135/0x00000202
> [  151.372524] 3 locks held by tc/1135:
> [  151.372527]  #0:  (rtnl_mutex){+.+.}, at: [<ffffffff98826e5b>] rtnetlink_rcv_msg+0x23b/0x5f0
> [  151.372544]  #1:  (&qdisc_tx_lock){+...}, at: [<ffffffffc07a5f0f>] htb_change_class+0x55f/0x880 [sch_htb]
> [  151.372560]  #2:  (rcu_sched_state.barrier_mutex){+.+.}, at: [<ffffffff9810bbbf>] _rcu_barrier+0x2f/0x170
> [  151.372575] Modules linked in: sch_sfq sch_htb ppdev input_leds serio_raw joydev parport_pc parport i2c_piix4 mac_hid ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi autofs4 btrfs zstd_decompress zstd_compress xxhash raid10 raid456 libcrc32c async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq raid1 raid0 multipath linear qxl drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm drm crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel aes_x86_64 crypto_simd cryptd glue_helper psmouse floppy pata_acpi hid_generic usbhid hid
> [  151.372748] CPU: 2 PID: 1135 Comm: tc Tainted: G        W       4.14.15 #2
> [  151.372751] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
> [  151.372753] Call Trace:
> [  151.372759]  dump_stack+0x7c/0xbe
> [  151.372767]  __schedule_bug+0x62/0x90
> [  151.372772]  __schedule+0x7d9/0xb80
> [  151.372788]  schedule+0x39/0x90
> [  151.372793]  schedule_timeout+0x24d/0x5c0
> [  151.372813]  ? mark_held_locks+0x71/0xa0
> [  151.372825]  ? wait_for_completion+0x12e/0x1a0
> [  151.372829]  wait_for_completion+0x12e/0x1a0
> [  151.372835]  ? wake_up_q+0x60/0x60
> [  151.372846]  _rcu_barrier+0x11a/0x170
> [  151.372853]  tcf_block_put+0x7f/0xa0
> [  151.372860]  sfq_destroy+0x15/0x50 [sch_sfq]
> [  151.372866]  qdisc_destroy+0x6c/0xe0
> [  151.372872]  htb_change_class+0x704/0x880 [sch_htb]
> [  151.372894]  tc_ctl_tclass+0x193/0x3c0
> [  151.372918]  rtnetlink_rcv_msg+0x270/0x5f0
> [  151.372932]  ? rtnetlink_put_metrics+0x1c0/0x1c0
> [  151.372940]  netlink_rcv_skb+0xde/0x110
> [  151.372952]  netlink_unicast+0x1e4/0x310
> [  151.372961]  netlink_sendmsg+0x2dc/0x3c0
> [  151.372977]  sock_sendmsg+0x30/0x40
> [  151.372983]  ___sys_sendmsg+0x2b9/0x2d0
> [  151.373010]  ? __handle_mm_fault+0x7f8/0x1120
> [  151.373026]  ? __do_page_fault+0x2a5/0x530
> [  151.373037]  ? __sys_sendmsg+0x51/0x90
> [  151.373042]  __sys_sendmsg+0x51/0x90
> [  151.373061]  entry_SYSCALL_64_fastpath+0x29/0xa0
> [  151.373065] RIP: 0033:0x7f7049397490
> [  151.373068] RSP: 002b:00007ffd0c432f48 EFLAGS: 00000246
> [  151.373306] NOHZ: local_softirq_pending 202
> [  151.400331] ------------[ cut here ]------------
> [  151.400342] WARNING: CPU: 2 PID: 1135 at net/core/skbuff.c:615 skb_release_head_state+0x4b/0x50
> [  151.400345] Modules linked in: sch_sfq sch_htb ppdev input_leds serio_raw joydev parport_pc parport i2c_piix4 mac_hid ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi autofs4 btrfs zstd_decompress zstd_compress xxhash raid10 raid456 libcrc32c async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq raid1 raid0 multipath linear qxl drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm drm crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel aes_x86_64 crypto_simd cryptd glue_helper psmouse floppy pata_acpi hid_generic usbhid hid
> [  151.400521] CPU: 2 PID: 1135 Comm: tc Tainted: G        W       4.14.15 #2
> [  151.400524] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
> [  151.400527] task: ffff980e7b050000 task.stack: ffffa3ca00578000
> [  151.400532] RIP: 0010:skb_release_head_state+0x4b/0x50
> [  151.400536] RSP: 0018:ffffa3ca0057bc38 EFLAGS: 00010206
> [  151.400543] RAX: ffffffff9884c9a0 RBX: ffff980e7b18c800 RCX: 0000000000000002
> [  151.400546] RDX: 00000000000f0000 RSI: 00000000ffffffff RDI: 0000000000000000
> [  151.400550] RBP: ffff980e72d9f800 R08: 0000000000000004 R09: 0000000000000000
> [  151.400553] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000868
> [  151.400556] R13: ffff980e7b18c800 R14: 0000000000000000 R15: 0000000000000000
> [  151.400560] FS:  00007f7049d82700(0000) GS:ffff980e7e200000(0000) knlGS:0000000000000000
> [  151.400564] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [  151.400567] CR2: 00007fb14b0f74a0 CR3: 000000003b142004 CR4: 00000000003606e0
> [  151.400574] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [  151.400578] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [  151.400581] Call Trace:
> [  151.400589]  skb_release_all+0xe/0x30
> [  151.400594]  consume_skb+0x43/0x140
> [  151.400603]  netlink_unicast+0x1ec/0x310
> [  151.400613]  netlink_sendmsg+0x2dc/0x3c0
> [  151.400630]  sock_sendmsg+0x30/0x40
> [  151.400637]  ___sys_sendmsg+0x2b9/0x2d0
> [  151.400667]  ? __handle_mm_fault+0x7f8/0x1120
> [  151.400685]  ? __do_page_fault+0x2a5/0x530
> [  151.400697]  ? __sys_sendmsg+0x51/0x90
> [  151.400702]  __sys_sendmsg+0x51/0x90
> [  151.400724]  entry_SYSCALL_64_fastpath+0x29/0xa0
> [  151.400729] RIP: 0033:0x7f7049397490
> [  151.400732] RSP: 002b:00007ffd0c432f48 EFLAGS: 00000246
> [  151.400755] Code: 48 8b 43 60 48 85 c0 74 20 65 8b 15 b0 c2 81 67 81 e2 00 00 0f 00 75 13 48 89 df 5b ff e0 48 83 e7 fe e8 a9 27 02 00 eb cf 5b c3 <0f> ff eb e9 90 0f 1f 44 00 00 53 48 89 fb e8 a2 ff ff ff 48 83
> [  151.400935] ---[ end trace a2dc1d508339e762 ]---
> [  151.400954] show_signal_msg: 5 callbacks suppressed
> [  151.400957] tc[1135]: segfault at 7ffd0c434000 ip 00007f7049401af8 sp 00007ffd0c432f48 error 6
> [  151.401033] BUG: scheduling while atomic: tc/1135/0x7ffffe00
> [  151.401104] no locks held by tc/1135.
> [  151.401107] Modules linked in: sch_sfq sch_htb ppdev input_leds serio_raw joydev parport_pc parport i2c_piix4 mac_hid ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi autofs4 btrfs zstd_decompress zstd_compress xxhash raid10 raid456 libcrc32c async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq raid1 raid0 multipath linear qxl drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm drm crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel aes_x86_64 crypto_simd cryptd glue_helper psmouse floppy pata_acpi hid_generic usbhid hid
> [  151.401277] CPU: 2 PID: 1135 Comm: tc Tainted: G        W       4.14.15 #2
> [  151.401281] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
> [  151.401284] Call Trace:
> [  151.401291]  dump_stack+0x7c/0xbe
> [  151.401300]  __schedule_bug+0x62/0x90
> [  151.401306]  __schedule+0x7d9/0xb80
> [  151.401323]  schedule+0x39/0x90
> [  151.401329]  schedule_timeout+0x24d/0x5c0
> [  151.401334]  ? try_to_wake_up+0x55/0x550
> [  151.401351]  ? wait_for_completion+0x126/0x1a0
> [  151.401366]  ? wait_for_completion+0x12e/0x1a0
> [  151.401371]  wait_for_completion+0x12e/0x1a0
> [  151.401377]  ? wake_up_q+0x60/0x60
> [  151.401389]  call_usermodehelper_exec+0x143/0x170
> [  151.401402]  ? wait_for_completion+0x49/0x1a0
> [  151.401415]  do_coredump+0xb8a/0x10e0
> [  151.401466]  get_signal+0x3d0/0x8f0
> [  151.401488]  do_signal+0x36/0x700
> [  151.401493]  ? force_sig_info+0xca/0xe0
> [  151.401504]  ? force_sig_info_fault+0x97/0xf0
> [  151.401519]  ? __bad_area_nosemaphore+0x168/0x1a0
> [  151.401537]  exit_to_usermode_loop+0x80/0xc0
> [  151.401543]  ? async_page_fault+0x36/0x60
> [  151.401550]  prepare_exit_to_usermode+0x7a/0x90
> [  151.401557]  retint_user+0x8/0x18
> [  151.401562] RIP: 0033:0x7f7049401af8
> [  151.401565] RSP: 002b:00007ffd0c432f48 EFLAGS: 00010207
> [  151.401571] RAX: 0000000000000000 RBX: 000000000064cb00 RCX: 0000000000006fd0
> [  151.401575] RDX: 0000000000008000 RSI: 00007ffd0c43afd0 RDI: 00007ffd0c434000
> [  151.401578] RBP: 000000005a6f436a R08: 0000000000000014 R09: 0000000000000000
> [  151.401581] R10: 00000000000005e7 R11: 0000000000000246 R12: 00007ffd0c432f90
> [  151.401584] R13: 00007ffd0c432fd0 R14: 0000000000655aa0 R15: 0000000000000000
>
> [  168.036082] ========================================================
> [  168.037902] WARNING: possible irq lock inversion dependency detected
> [  168.039397] 4.14.15 #2 Tainted: G        W
> [  168.040574] --------------------------------------------------------
> [  168.041051] swapper/3/0 just changed the state of lock:
> [  168.041520]  (&qdisc_tx_lock){+.-.}, at: [<ffffffff98811e2a>] __dev_queue_xmit+0x24a/0x9a0
> [  168.042009] but this lock took another, SOFTIRQ-unsafe lock in the past:
> [  168.042486]  (rcu_sched_state.barrier_mutex){+.+.}
> [  168.042488]
>
>                and interrupts could create inverse lock ordering between them.
>
> [  168.044723]
>                other info that might help us debug this:
> [  168.045509]  Possible interrupt unsafe locking scenario:
>
> [  168.046288]        CPU0                    CPU1
> [  168.046649]        ----                    ----
> [  168.047009]   lock(rcu_sched_state.barrier_mutex);
> [  168.047372]                                local_irq_disable();
> [  168.047742]                                lock(&qdisc_tx_lock);
> [  168.048112]                                lock(rcu_sched_state.barrier_mutex);
> [  168.048504]   <Interrupt>
> [  168.048871]     lock(&qdisc_tx_lock);
> [  168.049240]
>                 *** DEADLOCK ***
>
> [  168.050329] 4 locks held by swapper/3/0:
> [  168.050693]  #0:  (rcu_read_lock){....}, at: [<ffffffff9881355a>] netif_receive_skb_internal+0x2a/0x360
> [  168.051082]  #1:  (rcu_read_lock){....}, at: [<ffffffff9885e836>] ip_local_deliver_finish+0x26/0x1f0
> [  168.051472]  #2:  (rcu_read_lock_bh){....}, at: [<ffffffff9886389c>] ip_finish_output2+0xac/0x650
> [  168.051868]  #3:  (rcu_read_lock_bh){....}, at: [<ffffffff98811c3e>] __dev_queue_xmit+0x5e/0x9a0
> [  168.052266]
>                the shortest dependencies between 2nd lock and 1st lock:
> [  168.053089]  -> (rcu_sched_state.barrier_mutex){+.+.} ops: 3 {
> [  168.053504]     HARDIRQ-ON-W at:
> [  168.053900]                       lock_acquire+0xec/0x1e0
> [  168.054301]                       __mutex_lock+0x92/0x9a0
> [  168.054698]                       _rcu_barrier+0x2f/0x170
> [  168.055094]                       slab_caches_to_rcu_destroy_workfn+0x95/0xe0
> [  168.055522]                       process_one_work+0x204/0x650
> [  168.055922]                       worker_thread+0x4d/0x3e0
> [  168.056316]                       kthread+0x10a/0x140
> [  168.056717]                       ret_from_fork+0x3a/0x50
> [  168.057107]     SOFTIRQ-ON-W at:
> [  168.057494]                       lock_acquire+0xec/0x1e0
> [  168.057886]                       __mutex_lock+0x92/0x9a0
> [  168.058267]                       _rcu_barrier+0x2f/0x170
> [  168.058641]                       slab_caches_to_rcu_destroy_workfn+0x95/0xe0
> [  168.059016]                       process_one_work+0x204/0x650
> [  168.059386]                       worker_thread+0x4d/0x3e0
> [  168.059751]                       kthread+0x10a/0x140
> [  168.060109]                       ret_from_fork+0x3a/0x50
> [  168.060468]     INITIAL USE at:
> [  168.060808]                      lock_acquire+0xec/0x1e0
> [  168.061147]                      __mutex_lock+0x92/0x9a0
> [  168.061484]                      _rcu_barrier+0x2f/0x170
> [  168.061825]                      slab_caches_to_rcu_destroy_workfn+0x95/0xe0
> [  168.062166]                      process_one_work+0x204/0x650
> [  168.062502]                      worker_thread+0x4d/0x3e0
> [  168.062843]                      kthread+0x10a/0x140
> [  168.063180]                      ret_from_fork+0x3a/0x50
> [  168.063514]   }
> [  168.063857]   ... key      at: [<ffffffff992798b0>] rcu_sched_state+0x8530/0x8800
> [  168.064200]   ... acquired at:
> [  168.064554]    __mutex_lock+0x92/0x9a0
> [  168.064897]    _rcu_barrier+0x2f/0x170
> [  168.065236]    tcf_block_put+0x7f/0xa0
> [  168.065599]    sfq_destroy+0x15/0x50 [sch_sfq]
> [  168.065940]    qdisc_destroy+0x6c/0xe0
> [  168.066277]    htb_change_class+0x704/0x880 [sch_htb]
> [  168.066618]    tc_ctl_tclass+0x193/0x3c0
> [  168.066960]    rtnetlink_rcv_msg+0x270/0x5f0
> [  168.067306]    netlink_rcv_skb+0xde/0x110
> [  168.067653]    netlink_unicast+0x1e4/0x310
> [  168.067999]    netlink_sendmsg+0x2dc/0x3c0
> [  168.068332]    sock_sendmsg+0x30/0x40
> [  168.068713]    ___sys_sendmsg+0x2b9/0x2d0
> [  168.069036]    __sys_sendmsg+0x51/0x90
> [  168.069357]    entry_SYSCALL_64_fastpath+0x29/0xa0
>
> [  168.069974] -> (&qdisc_tx_lock){+.-.} ops: 5 {
> [  168.070283]    HARDIRQ-ON-W at:
> [  168.070587]                     lock_acquire+0xec/0x1e0
> [  168.070901]                     _raw_spin_lock_bh+0x38/0x70
> [  168.071212]                     htb_change_class+0x55f/0x880 [sch_htb]
> [  168.071526]                     tc_ctl_tclass+0x193/0x3c0
> [  168.071838]                     rtnetlink_rcv_msg+0x270/0x5f0
> [  168.072148]                     netlink_rcv_skb+0xde/0x110
> [  168.072466]                     netlink_unicast+0x1e4/0x310
> [  168.072774]                     netlink_sendmsg+0x2dc/0x3c0
> [  168.073080]                     sock_sendmsg+0x30/0x40
> [  168.073384]                     ___sys_sendmsg+0x2b9/0x2d0
> [  168.073703]                     __sys_sendmsg+0x51/0x90
> [  168.074005]                     entry_SYSCALL_64_fastpath+0x29/0xa0
> [  168.074312]    IN-SOFTIRQ-W at:
> [  168.074615]                     lock_acquire+0xec/0x1e0
> [  168.074948]                     _raw_spin_lock+0x30/0x70
> [  168.075260]                     __dev_queue_xmit+0x24a/0x9a0
> [  168.075567]                     ip_finish_output2+0x4c6/0x650
> [  168.075877]                     ip_output+0x7c/0x250
> [  168.076183]                     tcp_v4_send_synack+0x8e/0x120
> [  168.076497]                     tcp_conn_request+0xaf4/0xc80
> [  168.076804]                     tcp_rcv_state_process+0x233/0xf30
> [  168.077114]                     tcp_v4_do_rcv+0xae/0x1c0
> [  168.077419]                     tcp_v4_rcv+0xa2e/0xa80
> [  168.077720]                     ip_local_deliver_finish+0x97/0x1f0
> [  168.078024]                     ip_local_deliver+0x71/0x210
> [  168.078329]                     ip_rcv+0x271/0x4c0
> [  168.078631]                     __netif_receive_skb_core+0x79c/0xd20
> [  168.078937]                     netif_receive_skb_internal+0x1a7/0x360
> [  168.079241]                     napi_gro_receive+0x137/0x1b0
> [  168.079539]                     receive_buf+0x444/0x1730
> [  168.079837]                     virtnet_poll+0x119/0x290
> [  168.080136]                     net_rx_action+0x1fd/0x410
> [  168.080444]                     __do_softirq+0xc8/0x49a
> [  168.080743]                     irq_exit+0xc1/0xd0
> [  168.081039]                     do_IRQ+0x60/0x110
> [  168.081333]                     ret_from_intr+0x0/0x22
> [  168.081624]                     native_safe_halt+0x2/0x10
> [  168.081917]                     default_idle+0x1d/0x1a0
> [  168.082209]                     do_idle+0x170/0x200
> [  168.082501]                     cpu_startup_entry+0x6f/0x80
> [  168.082797]                     start_secondary+0x197/0x1f0
> [  168.083093]                     secondary_startup_64+0xa5/0xb0
> [  168.083404]    INITIAL USE at:
> [  168.083697]                    lock_acquire+0xec/0x1e0
> [  168.083995]                    _raw_spin_lock_bh+0x38/0x70
> [  168.084293]                    htb_change_class+0x55f/0x880 [sch_htb]
> [  168.084614]                    tc_ctl_tclass+0x193/0x3c0
> [  168.084922]                    rtnetlink_rcv_msg+0x270/0x5f0
> [  168.085218]                    netlink_rcv_skb+0xde/0x110
> [  168.085514]                    netlink_unicast+0x1e4/0x310
> [  168.085807]                    netlink_sendmsg+0x2dc/0x3c0
> [  168.086096]                    sock_sendmsg+0x30/0x40
> [  168.086384]                    ___sys_sendmsg+0x2b9/0x2d0
> [  168.086673]                    __sys_sendmsg+0x51/0x90
> [  168.086963]                    entry_SYSCALL_64_fastpath+0x29/0xa0
> [  168.087256]  }
> [  168.087544]  ... key      at: [<ffffffff9a7cc448>] qdisc_tx_lock+0x0/0x8
> [  168.087845]  ... acquired at:
> [  168.088144]    mark_lock+0x30a/0x5c0
> [  168.088448]    __lock_acquire+0x3a5/0x1510
> [  168.088743]    lock_acquire+0xec/0x1e0
> [  168.089035]    _raw_spin_lock+0x30/0x70
> [  168.089328]    __dev_queue_xmit+0x24a/0x9a0
> [  168.089621]    ip_finish_output2+0x4c6/0x650
> [  168.089915]    ip_output+0x7c/0x250
> [  168.090207]    tcp_v4_send_synack+0x8e/0x120
> [  168.090500]    tcp_conn_request+0xaf4/0xc80
> [  168.090794]    tcp_rcv_state_process+0x233/0xf30
> [  168.091089]    tcp_v4_do_rcv+0xae/0x1c0
> [  168.091382]    tcp_v4_rcv+0xa2e/0xa80
> [  168.091675]    ip_local_deliver_finish+0x97/0x1f0
> [  168.091971]    ip_local_deliver+0x71/0x210
> [  168.092265]    ip_rcv+0x271/0x4c0
> [  168.092561]    __netif_receive_skb_core+0x79c/0xd20
> [  168.092857]    netif_receive_skb_internal+0x1a7/0x360
> [  168.093154]    napi_gro_receive+0x137/0x1b0
> [  168.093448]    receive_buf+0x444/0x1730
> [  168.093758]    virtnet_poll+0x119/0x290
> [  168.094050]    net_rx_action+0x1fd/0x410
> [  168.094355]    __do_softirq+0xc8/0x49a
> [  168.094647]    irq_exit+0xc1/0xd0
> [  168.094937]    do_IRQ+0x60/0x110
> [  168.095227]    ret_from_intr+0x0/0x22
> [  168.095518]    native_safe_halt+0x2/0x10
> [  168.095809]    default_idle+0x1d/0x1a0
> [  168.096099]    do_idle+0x170/0x200
> [  168.096395]    cpu_startup_entry+0x6f/0x80
> [  168.096687]    start_secondary+0x197/0x1f0
> [  168.096978]    secondary_startup_64+0xa5/0xb0
>
> [  168.097552]
>                stack backtrace:
> [  168.098105] CPU: 3 PID: 0 Comm: swapper/3 Tainted: G        W       4.14.15 #2
> [  168.098393] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
> [  168.098690] Call Trace:
> [  168.098986]  <IRQ>
> [  168.099278]  dump_stack+0x7c/0xbe
> [  168.099574]  print_irq_inversion_bug.part.43+0x198/0x1a3
> [  168.099877]  check_usage_forwards+0x17a/0x180
> [  168.100182]  ? __save_stack_trace+0x82/0x100
> [  168.100493]  ? secondary_startup_64+0xa5/0xb0
> [  168.100799]  ? check_usage_backwards+0x180/0x180
> [  168.101106]  ? mark_lock+0x30a/0x5c0
> [  168.101410]  mark_lock+0x30a/0x5c0
> [  168.101709]  __lock_acquire+0x3a5/0x1510
> [  168.102005]  ? __lock_acquire+0xc21/0x1510
> [  168.102303]  ? lock_acquire+0xec/0x1e0
> [  168.102598]  lock_acquire+0xec/0x1e0
> [  168.102893]  ? __dev_queue_xmit+0x24a/0x9a0
> [  168.103191]  _raw_spin_lock+0x30/0x70
> [  168.103488]  ? __dev_queue_xmit+0x24a/0x9a0
> [  168.103803]  __dev_queue_xmit+0x24a/0x9a0
> [  168.104124]  ip_finish_output2+0x4c6/0x650
> [  168.104437]  ? ip_output+0x7c/0x250
> [  168.104733]  ip_output+0x7c/0x250
> [  168.105028]  ? tcp_make_synack+0x38b/0x4b0
> [  168.105325]  tcp_v4_send_synack+0x8e/0x120
> [  168.105623]  ? _raw_spin_unlock+0x24/0x30
> [  168.105920]  ? inet_ehash_insert+0xfa/0x170
> [  168.106218]  tcp_conn_request+0xaf4/0xc80
> [  168.106519]  ? tcp_rcv_state_process+0x233/0xf30
> [  168.106818]  tcp_rcv_state_process+0x233/0xf30
> [  168.107119]  ? tcp_v4_do_rcv+0xae/0x1c0
> [  168.107416]  tcp_v4_do_rcv+0xae/0x1c0
> [  168.107713]  tcp_v4_rcv+0xa2e/0xa80
> [  168.108010]  ip_local_deliver_finish+0x97/0x1f0
> [  168.108310]  ip_local_deliver+0x71/0x210
> [  168.108614]  ip_rcv+0x271/0x4c0
> [  168.108953]  ? packet_rcv+0x3d/0x3a0
> [  168.109261]  __netif_receive_skb_core+0x79c/0xd20
> [  168.109564]  ? lock_acquire+0xec/0x1e0
> [  168.109867]  ? dev_gro_receive+0x26b/0x5c0
> [  168.110172]  ? netif_receive_skb_internal+0x2a/0x360
> [  168.110480]  ? netif_receive_skb_internal+0x1a7/0x360
> [  168.110892]  ? netif_receive_skb_internal+0x56/0x360
> [  168.111197]  netif_receive_skb_internal+0x1a7/0x360
> [  168.111503]  napi_gro_receive+0x137/0x1b0
> [  168.111806]  receive_buf+0x444/0x1730
> [  168.112115]  ? __lock_acquire+0x2e7/0x1510
> [  168.112439]  ? vring_unmap_one+0x16/0x70
> [  168.112754]  ? detach_buf+0x68/0x110
> [  168.113052]  virtnet_poll+0x119/0x290
> [  168.113339]  ? __wake_up_common_lock+0x89/0xc0
> [  168.113675]  net_rx_action+0x1fd/0x410
> [  168.113970]  ? credit_entropy_bits+0x313/0x350
> [  168.114262]  __do_softirq+0xc8/0x49a
> [  168.114551]  irq_exit+0xc1/0xd0
> [  168.114837]  do_IRQ+0x60/0x110
> [  168.115121]  common_interrupt+0xa2/0xa2
> [  168.115404]  </IRQ>
> [  168.115684] RIP: 0010:native_safe_halt+0x2/0x10
> [  168.115969] RSP: 0018:ffffa3ca001ffec8 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff2e
> [  168.116267] RAX: ffff980e7db91b40 RBX: ffff980e7db91b40 RCX: 0000000000000000
> [  168.116578] RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffff980e7db91b40
> [  168.116886] RBP: 0000000000000003 R08: 0000000000000001 R09: 0000000000000000
> [  168.117194] R10: 0000000000000000 R11: 0000000000000000 R12: ffff980e7db91b40
> [  168.117501] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
> [  168.117811]  default_idle+0x1d/0x1a0
> [  168.118116]  do_idle+0x170/0x200
> [  168.118419]  cpu_startup_entry+0x6f/0x80
> [  168.118725]  start_secondary+0x197/0x1f0
> [  168.119029]  secondary_startup_64+0xa5/0xb0

Re: iproute2 4.14.1 tc class add come to kernel-panic

[Cong Wang]

On Mon, Jan 29, 2018 at 9:03 AM, Cong Wang <xiyou.wangcong@gmail.com> wrote:
> On Mon, Jan 29, 2018 at 8:00 AM, Stephen Hemminger
> <stephen@networkplumber.org> wrote:
>> On Mon, 29 Jan 2018 16:18:07 +0100
>> "Roland Franke" <fli4l@franke-prem.de> wrote:
>>
>>> Hello,
>>>
>>> > To: Roland Franke ; netdev@vger.kernel.org
>>> > Subject: Re: BUG: iproute2 4.14.1 tc class add come to kernel-panic
>>> >>
>>> >> tc qdisc add dev eth0 root handle 20: htb default 4 r2q 1
>>> >> tc class add dev eth0 parent 20: classid 20:7 htb rate 10000kbit
>>> >> tc qdisc add dev eth0 parent 20:7 sfq perturb 10
>>> >> tc class add dev eth0 parent 20:7 classid 20:1 htb rate 200kbit ceil
>>> >> 10000kbit prio 0
>>> >>
>>> >> I become an Kernel-panic with the following output:
>>> >> kern.err kernel: BUG: scheduling while atomic: tc/1036/0x00000200
>>> >
>>>
>>> > Would you have a stack trace to share with us ?
>>>
>>> As i will be an absolute newby here, i will not know how to
>>> get the stack trace out.
>>> When i will get some information how to get this, i can try to
>>> give you this information.
>>> But by my last tests i made the first 3 commands on an console
>>> and had no error. Only by typing the last line i will get the error and
>>> here i get actally only the "kern.err kernel: BUG: ....." message.
>>>
>>> Roland
>>
>> It generates this with lockdep (on 4.15)
>>
>> [  151.355076] HTB: quantum of class 200007 is big. Consider r2q change.
>> [  151.371495] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:747
>> [  151.371815] in_atomic(): 1, irqs_disabled(): 0, pid: 1135, name: tc
>> [  151.371875] 2 locks held by tc/1135:
>> [  151.371878]  #0:  (rtnl_mutex){+.+.}, at: [<ffffffff98826e5b>] rtnetlink_rcv_msg+0x23b/0x5f0
>> [  151.371899]  #1:  (&qdisc_tx_lock){+...}, at: [<ffffffffc07a5f0f>] htb_change_class+0x55f/0x880 [sch_htb]
>> [  151.371918] CPU: 2 PID: 1135 Comm: tc Not tainted 4.14.15 #2
>> [  151.371921] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
>> [  151.371924] Call Trace:
>> [  151.371934]  dump_stack+0x7c/0xbe
>> [  151.371944]  ___might_sleep+0x21e/0x250
>> [  151.371953]  __mutex_lock+0x59/0x9a0
>> [  151.371960]  ? lock_acquire+0xec/0x1e0
>> [  151.371973]  ? __raw_spin_lock_init+0x1c/0x50
>> [  151.371990]  ? _rcu_barrier+0x2f/0x170
>> [  151.371995]  ? __lockdep_init_map+0x5c/0x1d0
>> [  151.371998]  _rcu_barrier+0x2f/0x170
>> [  151.372006]  tcf_block_put+0x7f/0xa0
>> [  151.372013]  sfq_destroy+0x15/0x50 [sch_sfq]
>> [  151.372021]  qdisc_destroy+0x6c/0xe0
>> [  151.372028]  htb_change_class+0x704/0x880 [sch_htb]
>
>
> We hold qdisc tree spinlock but call rcu_barrier() in
> mini_qdisc_pair_swap()...

Well, not min_qdisc things, but it should be resolved by:

commit efbf78973978b0d25af59bc26c8013a942af6e64
Author: Cong Wang <xiyou.wangcong@gmail.com>
Date:   Mon Dec 4 10:48:18 2017 -0800

    net_sched: get rid of rcu_barrier() in tcf_block_put_ext()

Re: iproute2 4.14.1 tc class add come to kernel-panic

[Roland Franke]

Hello,

> On Mon, Jan 29, 2018 at 9:03 AM, Cong Wang <xiyou.wangcong@gmail.com> 
> wrote:
>> On Mon, Jan 29, 2018 at 8:00 AM, Stephen Hemminger
>> <stephen@networkplumber.org> wrote:
>>> On Mon, 29 Jan 2018 16:18:07 +0100
>>> "Roland Franke" <fli4l@franke-prem.de> wrote:
>>>
>>>> Hello,
>>>>
>>>> > To: Roland Franke ; netdev@vger.kernel.org
>>>> > Subject: Re: BUG: iproute2 4.14.1 tc class add come to kernel-panic
>>>> >>
>>>> >> tc qdisc add dev eth0 root handle 20: htb default 4 r2q 1
>>>> >> tc class add dev eth0 parent 20: classid 20:7 htb rate 10000kbit
>>>> >> tc qdisc add dev eth0 parent 20:7 sfq perturb 10
>>>> >> tc class add dev eth0 parent 20:7 classid 20:1 htb rate 200kbit ceil
>>>> >> 10000kbit prio 0
>>>> >>
>>>> >> I become an Kernel-panic with the following output:
>>>> >> kern.err kernel: BUG: scheduling while atomic: tc/1036/0x00000200
>>>> >
>>>>
>>>> > Would you have a stack trace to share with us ?
>>>>
>>>> As i will be an absolute newby here, i will not know how to
>>>> get the stack trace out.
>>>> When i will get some information how to get this, i can try to
>>>> give you this information.
>>>> But by my last tests i made the first 3 commands on an console
>>>> and had no error. Only by typing the last line i will get the error and
>>>> here i get actally only the "kern.err kernel: BUG: ....." message.
>>>>
>>>> Roland
>>>
>>> It generates this with lockdep (on 4.15)
>>>
>>> [  151.355076] HTB: quantum of class 200007 is big. Consider r2q change.
>>
>>
>> We hold qdisc tree spinlock but call rcu_barrier() in
>> mini_qdisc_pair_swap()...

> Well, not min_qdisc things, but it should be resolved by:

> commit efbf78973978b0d25af59bc26c8013a942af6e64
> Author: Cong Wang <xiyou.wangcong@gmail.com>
> Date:   Mon Dec 4 10:48:18 2017 -0800

>     net_sched: get rid of rcu_barrier() in tcf_block_put_ext()

Against what kernel-version was this be made?
patch from https://patchwork.ozlabs.org/patch/844372/
will not fit against kernel 4.14.15

Re: iproute2 4.14.1 tc class add come to kernel-panic

[Cong Wang]

On Tue, Jan 30, 2018 at 9:46 AM, Roland Franke <fli4l@franke-prem.de> wrote:
> Hello,
>
>> Well, not min_qdisc things, but it should be resolved by:
>
>
>> commit efbf78973978b0d25af59bc26c8013a942af6e64
>> Author: Cong Wang <xiyou.wangcong@gmail.com>
>> Date:   Mon Dec 4 10:48:18 2017 -0800
>
>
>>     net_sched: get rid of rcu_barrier() in tcf_block_put_ext()
>
>
> Against what kernel-version was this be made?
> patch from https://patchwork.ozlabs.org/patch/844372/
> will not fit against kernel 4.14.15
>

It is merged during 4.15 window, it was to address a performance
issue, I don't realize it fixes any bug until you report this.

If you need, we can ask DaveM to queue it for stable, but it may
need some other commit too.

Thanks.

Re: iproute2 4.14.1 tc class add come to kernel-panic

[Roland Franke]

Hello,

> On Tue, Jan 30, 2018 at 9:46 AM, Roland Franke <fli4l@franke-prem.de> 
> wrote:
>> Hello,
>>
>>> Well, not min_qdisc things, but it should be resolved by:
>>
>>> commit efbf78973978b0d25af59bc26c8013a942af6e64
>>> Author: Cong Wang <xiyou.wangcong@gmail.com>
>>> Date:   Mon Dec 4 10:48:18 2017 -0800
>>
>>>     net_sched: get rid of rcu_barrier() in tcf_block_put_ext()
>>
>>
>> Against what kernel-version was this be made?
>> patch from https://patchwork.ozlabs.org/patch/844372/
>> will not fit against kernel 4.14.15
>>

> It is merged during 4.15 window, it was to address a performance
> issue, I don't realize it fixes any bug until you report this.

> If you need, we can ask DaveM to queue it for stable, but it may
> need some other commit too.

It is not for me. It is a general question, if tc schould work with
the requested function general not with the kernel-line 4.14 (As
i was thinking that this should be come to a very long support.
(As i was suggest to read in an german page for computers; but
it may be a mistake from my side)
Or if the 4.14 series come to a "short end" and then it take no
matter when the function not work.

Best regards. 

Re: iproute2 4.14.1 tc class add come to kernel-panic

[Cong Wang]

On Tue, Jan 30, 2018 at 11:46 PM, Roland Franke <fli4l@franke-prem.de> wrote:
> Hello,
>
>> On Tue, Jan 30, 2018 at 9:46 AM, Roland Franke <fli4l@franke-prem.de>
>> wrote:
>>>
>>> Hello,
>>>
>>>> Well, not min_qdisc things, but it should be resolved by:
>>>
>>>
>>>> commit efbf78973978b0d25af59bc26c8013a942af6e64
>>>> Author: Cong Wang <xiyou.wangcong@gmail.com>
>>>> Date:   Mon Dec 4 10:48:18 2017 -0800
>>>
>>>
>>>>     net_sched: get rid of rcu_barrier() in tcf_block_put_ext()
>>>
>>>
>>>
>>> Against what kernel-version was this be made?
>>> patch from https://patchwork.ozlabs.org/patch/844372/
>>> will not fit against kernel 4.14.15
>>>
>
>> It is merged during 4.15 window, it was to address a performance
>> issue, I don't realize it fixes any bug until you report this.
>
>
>> If you need, we can ask DaveM to queue it for stable, but it may
>> need some other commit too.
>
>
> It is not for me. It is a general question, if tc schould work with
> the requested function general not with the kernel-line 4.14 (As
> i was thinking that this should be come to a very long support.
> (As i was suggest to read in an german page for computers; but
> it may be a mistake from my side)
> Or if the 4.14 series come to a "short end" and then it take no
> matter when the function not work.
>

Sure, I will send a list of commits to backport to DaveM.

Thanks.

Re: iproute2 4.14.1 tc class add come to kernel-panic

[Roland Franke]

Hello,

>> Hello,
>>
>>>>> Well, not min_qdisc things, but it should be resolved by:
>>>>
>>>>
>>>>> commit efbf78973978b0d25af59bc26c8013a942af6e64
>>>>> Author: Cong Wang <xiyou.wangcong@gmail.com>
>>>>> Date:   Mon Dec 4 10:48:18 2017 -0800
>>>>
>>>>
>>>>>     net_sched: get rid of rcu_barrier() in tcf_block_put_ext()
>>>>
>>>>
>>>>
>>>> Against what kernel-version was this be made?
>>>> patch from https://patchwork.ozlabs.org/patch/844372/
>>>> will not fit against kernel 4.14.15
>>>>
>>
>>> It is merged during 4.15 window, it was to address a performance
>>> issue, I don't realize it fixes any bug until you report this.
>>
>>
>>> If you need, we can ask DaveM to queue it for stable, but it may
>>> need some other commit too.
>>
>>
>> It is not for me. It is a general question, if tc schould work with
>> the requested function general not with the kernel-line 4.14 (As
>> i was thinking that this should be come to a very long support.
>> (As i was suggest to read in an german page for computers; but
>> it may be a mistake from my side)
>> Or if the 4.14 series come to a "short end" and then it take no
>> matter when the function not work.
>>
>
> Sure, I will send a list of commits to backport to DaveM.
>
Only as information:
With Kernel 4.15(.0) i will get the same problem here by me.
At last: 
kern.err kernel: BUG: scheduling while atomic: tc/23022/0x00000200

Best regards,
Roland