Bug #7940

disabling LAGG causes system reboot on 2.4

Added by Vladimir Lind about 3 years ago. Updated almost 3 years ago.

Target version:
Start date:
Due date:
% Done:


Estimated time:
Affected Version:
Affected Architecture:


It looks very similar to this -

When Lagg interface goes down:

<6>carp: 5@lagg0_vlan56: MASTER -> INIT (hardware interface down)
<6>carp: demoted by 240 to 240 (interface down)
<7>ifa_maintain_loopback_route: deletion failed for interface lagg0_vlan56: 3
<7>ifa_maintain_loopback_route: deletion failed for interface lagg0_vlan56: 3
<6>carp: demoted by -240 to 0 (vhid removed)
<6>lagg0_vlan56: promiscuous mode disabled
<6>vlan15: changing name to 'lagg0_vlan56'
<6>lagg0_vlan56: promiscuous mode enabled
<6>carp: 5@lagg0_vlan56: INIT -> BACKUP (initialization complete)

Fatal trap 12: page fault while in kernel mode
cpuid = 0; apic id = 00
fault virtual address = 0x200
fault code = supervisor write data, page not present
instruction pointer = 0x20:0xffffffff80d81f14
stack pointer = 0x28:0xfffffe044dbf98b0
frame pointer = 0x28:0xfffffe044dbf9900
code segment = base 0x0, limit 0xfffff, type 0x1b = DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags = interrupt enabled, resume, IOPL = 0
current process = 12 (swi4: clock (0))
version.txt06000027613170320505 7614 ustarrootwheelFreeBSD 11.1-RELEASE-p1 #83 r313908+d77c47fe50c(RELENG_2_4_0): Tue Oct 10 06:48:42 CDT 2017

Ticket for reference -


#1 Updated by Jim Pingle about 3 years ago

  • Assignee set to Luiz Souza
  • Target version set to 2.4.1

That does look almost identical to #7119, we should check to see if those patches need any adjustments for FreeBSD 11.1.

#2 Updated by Jim Pingle about 3 years ago

  • Target version changed from 2.4.1 to 2.4.2

#3 Updated by Luiz Souza about 3 years ago

Please, can you post the backtrace of this crash ? (or upload the crashdump text file)

I can't reproduce this crash in my test devices, any specific details that I could try here ?

#4 Updated by Luiz Souza almost 3 years ago

  • Status changed from New to Confirmed

Ok, I found a way to reproduce this.

It is not really related to lagg, it is a race that happens at interface detach and when there are pending link layer requests.

It also happens with other interfaces (I can reproduce the same crash with VLANs at least).

I will continue to investigate.

#5 Updated by Luiz Souza almost 3 years ago

  • Status changed from Confirmed to Feedback
  • % Done changed from 0 to 100


The fix will be available on the next snapshot.

Testing this issue is non trivial, but still, I would appreciate some testing.


#6 Updated by Anonymous almost 3 years ago

could not replicate on 2.4.2.a.20171103.1355, not on HA though.

#7 Updated by Luiz Souza almost 3 years ago

  • Status changed from Feedback to Resolved

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