Bug 246305 - prism54pci (mac80211) always fails ipv6 duplicate address detection
prism54pci (mac80211) always fails ipv6 duplicate address detection
Product: Fedora
Classification: Fedora
Component: kernel (Show other bugs)
i386 Linux
low Severity low
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Assigned To: John W. Linville
Fedora Extras Quality Assurance
: 250252 (view as bug list)
Depends On:
  Show dependency treegraph
Reported: 2007-06-29 18:13 EDT by Mike Bonnet
Modified: 2007-11-30 17:12 EST (History)
3 users (show)

See Also:
Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
Last Closed: 2007-08-21 13:41:02 EDT
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Regression: ---
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Verified Versions:
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oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

Attachments (Terms of Use)
ipv6 broadcast packets seen by the prism54pci device when adding a link-local ipv6 address (424 bytes, application/octet-stream)
2007-06-29 18:13 EDT, Mike Bonnet
no flags Details

  None (edit)
Description Mike Bonnet 2007-06-29 18:13:04 EDT
Description of problem:
When an ipv6 link-local address is added (either automatically or manually) to a
prism54pci (mac80211) device, the address will always be marked "tentative", and
a "duplicate address detected!" message will be output in syslog.  This is
definitely not a duplicate address.  It looks like the device is seeing its own
broadcast packets, that the kernel sent out to perform ipv6 Neighbor Discovery.
 This may be similar to this bug:

Version-Release number of selected component (if applicable):

How reproducible:

Steps to Reproduce:
1. flush ipv6 addrs from the device (for consistency)
# ip -6 addr flush wlan1
2. manually add a unique ipv6 addr to the device
# ip -6 addr add fe80::209:5bff:feea:c06f/64 dev wlan1 scope link
3. look in syslog for the "duplicate address detected!" message
4. see that the address has been marked tentative
# ip -6 addr show wlan1
7: wlan1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qlen 1000
    inet6 fe80::209:5bff:feea:c06f/64 scope link tentative 
       valid_lft forever preferred_lft forever

Actual results:
"duplicate address detected!" in syslog, address is marked tentative and is unusable

Expected results:
no duplicate address detected, address not marked tentative

Additional info:
attached a wireshark capture of the ipv6 broadcast packets that the device sees
when the address is added
Comment 1 Mike Bonnet 2007-06-29 18:13:04 EDT
Created attachment 158274 [details]
ipv6 broadcast packets seen by the prism54pci device when adding a link-local ipv6 address
Comment 2 John W. Linville 2007-08-01 10:09:26 EDT
FWIW, I think this is a generic mac80211 problem.
Comment 3 John W. Linville 2007-08-02 14:51:00 EDT
*** Bug 250252 has been marked as a duplicate of this bug. ***
Comment 4 John W. Linville 2007-08-07 14:02:39 EDT
Please try the kernels here:


Do these avoid the "duplicate address" problem?
Comment 5 Pekka Savola 2007-08-08 01:05:20 EDT
Kernel 46 from koji seems to fix the problem on zd1211rw and IPv6 now works fine
(it appears as if IPv4 DHCP setup is much faster as well, but I didn't test it
thoroughly).  Thanks!
Comment 6 Mike Bonnet 2007-08-09 20:28:59 EDT no longer exhibits the "duplicate address" problem.  Awesome, thanks

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