Re: 2.6.29-rc8: Reported regressions from 2.6.28

[Jeff Chua <jeff.chua.linux@gmail.com>]

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On Mon, Mar 16, 2009 at 4:26 AM, Ingo Molnar <mingo@elte.hu> wrote:
> * Johannes Berg <johannes@sipsolutions.net> wrote:
>> that the commit he quotes doesn't even change the driver he's
>> working with.

Here's what I did, and it's repeatable.

Take the attached bisect log and replay it, and the last offending
commit is this ...
# git log
commit 71c11fb57b924c160297ccd9e1761db598d00ac2
Author: Johannes Berg <johannes@sipsolutions.net>
Date:   Tue Oct 28 18:29:48 2008 +0100

    b43/legacy: remove SSID code

Yes, this is not the real problem, but it's the last commit that cause
the problem, and I couldn't bisect further, typing the next "git
bisect bad" and the commit is

# git bisect bad
71c11fb57b924c160297ccd9e1761db598d00ac2 is first bad commit
commit 71c11fb57b924c160297ccd9e1761db598d00ac2
Author: Johannes Berg <johannes@sipsolutions.net>
Date:   Tue Oct 28 18:29:48 2008 +0100

    b43/legacy: remove SSID code


Johannes, Ok, this is not the commit causing the problem, but anything
after this commit doesn't associate with my hidden APs. I may not have
run over every single commits since, but 2.6.29-rc8 is definitely not
associating at all automatically -- only manually by specifying the
AP.

This bug is quite hard to trigger, and it doesn't shows easily in
2.6.28-rc3. May be once every 10 times you tried.



# git reset --hard 71c11fb57b924c160297ccd9e1761db598d00ac2

I've tried on two different Linksys's AP. Association with WAG354G  is
better than with WAG200G ... meaning it's harder to get association
failure on 2.6.28-rc3. 1/10 fail on WAG354G, and 9/10 fails on
WAG200G.

Here's how I associate with the AP.

# modprobe -r iwlagn
# modprobe iwlagn
# iwconfig wlan0 mode Managed
# ifconfig wlan0 up
# iwconfig wlan0 essid "myessid"
# iwconfig wlan0 key restricted "hex key"
# iwconfig wlan0 ap auto channel auto
# ... wait for association
# ping -c 3 <IP of the AP>
# shutdown the interface
# ifconfig wlan0 down
# modprobe -r iwlagn


Repeat these and it'll fail to associate. On WAG200G, can't associate
after 2nd attempt.


Next revert these two commits

commit 4607816f608b42a5379aca97ceed08378804c99f
Author: Johannes Berg <johannes@sipsolutions.net>
Date:   Tue Oct 28 18:25:43 2008 +0100

    iwlwifi: remove unused essid variable

commit a57a59f247b651e8ed6d3eeb7e2f9d83b83134c9
Author: Johannes Berg <johannes@sipsolutions.net>
Date:   Tue Oct 28 18:21:05 2008 +0100

    iwlwifi: remove implicit direct scan


With these patches reverted, associating with the APs are always
successful 10 out of 10 times with the same steps as above.

I've even used the bad modules and when it failed, I can associate
again with the patched module. Same 2.6.28-rc3 kernel.


Here's part of the dmesg
cfg80211: Using static regulatory domain info
cfg80211: Regulatory domain: US
        (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp)
        (2402000 KHz - 2472000 KHz @ 40000 KHz), (600 mBi, 2700 mBm)
        (5170000 KHz - 5190000 KHz @ 40000 KHz), (600 mBi, 2300 mBm)
        (5190000 KHz - 5210000 KHz @ 40000 KHz), (600 mBi, 2300 mBm)
        (5210000 KHz - 5230000 KHz @ 40000 KHz), (600 mBi, 2300 mBm)
        (5230000 KHz - 5330000 KHz @ 40000 KHz), (600 mBi, 2300 mBm)
        (5735000 KHz - 5835000 KHz @ 40000 KHz), (600 mBi, 3000 mBm)
cfg80211: Calling CRDA for country: US
iwlagn: Intel(R) Wireless WiFi Link AGN driver for Linux, 1.3.27ks
iwlagn: Copyright(c) 2003-2008 Intel Corporation
iwlagn 0000:03:00.0: PCI INT A -> GSI 17 (level, low) -> IRQ 17
iwlagn 0000:03:00.0: setting latency timer to 64
iwlagn: Detected Intel Wireless WiFi Link 4965AGN REV=0x4
iwlagn: Tunable channels: 11 802.11bg, 13 802.11a channels
iwlagn 0000:03:00.0: PCI INT A disabled
wmaster0 (iwlagn): not using net_device_ops yet
phy0: Selected rate control algorithm 'iwl-agn-rs'
wlan0 (iwlagn): not using net_device_ops yet
iwlagn 0000:03:00.0: PCI INT A -> GSI 17 (level, low) -> IRQ 17
iwlagn 0000:03:00.0: restoring config space at offset 0x1 (was
0x100102, writing 0
x100106)
iwlagn 0000:03:00.0: irq 28 for MSI/MSI-X
iwlagn 0000:03:00.0: firmware: requesting iwlwifi-4965-2.ucode
iwlagn loaded firmware version 228.57.2.23
Registered led device: iwl-phy0:radio
Registered led device: iwl-phy0:assoc
Registered led device: iwl-phy0:RX
Registered led device: iwl-phy0:TX
iwlagn: TX Power requested while scanning!

Anything I can help to debug further, just let me know.

Thanks,
Jeff.

[-- Attachment #2: bisect.log --]
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git bisect start
# bad: [0191b625ca5a46206d2fb862bb08f36f2fcb3b31] Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6
git bisect bad 0191b625ca5a46206d2fb862bb08f36f2fcb3b31
# good: [1d248b2593e92db6c51ca07235985a95c625a93f] Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband
git bisect good 1d248b2593e92db6c51ca07235985a95c625a93f
# bad: [7d359daafe12b36b6da7ec6247caddf534183aed] apne: convert to net_device_ops
git bisect bad 7d359daafe12b36b6da7ec6247caddf534183aed
# bad: [0a888fd1f6320d1d9318c58de9bca3cef41546d6] virtio_net: Recycle some more rx buffer pages
git bisect bad 0a888fd1f6320d1d9318c58de9bca3cef41546d6
# good: [c354e1246348e25c714e6b2973f3257183d06e2c] net: clean up net/ipv4/ipmr.c
git bisect good c354e1246348e25c714e6b2973f3257183d06e2c
# good: [f21f237cf55494c3a4209de323281a3b0528da10] Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
git bisect good f21f237cf55494c3a4209de323281a3b0528da10
# bad: [05a1e2d111c98340fb17ec702cf09450eec3a947] ath9k: Enable interrupts at the proper place
git bisect bad 05a1e2d111c98340fb17ec702cf09450eec3a947
# good: [4bab0ea1d42dd1927af9df6fbf0003fc00617c50] Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6
git bisect good 4bab0ea1d42dd1927af9df6fbf0003fc00617c50
# good: [0a95f56323ce93dac354c1b2d54bf959a985cf7d] sfc: Clean up non-volatile memory partitioning
git bisect good 0a95f56323ce93dac354c1b2d54bf959a985cf7d
# good: [1239cd58d237fa6ad501acaec8776262a5784ec8] wireless: move mesh config length constant
git bisect good 1239cd58d237fa6ad501acaec8776262a5784ec8
# bad: [17683c65c8a5f3f29f5408334992986b996d8205] ath5k: fix keytable type buglet in ath5k_hw_reset_key
git bisect bad 17683c65c8a5f3f29f5408334992986b996d8205
# bad: [71c11fb57b924c160297ccd9e1761db598d00ac2] b43/legacy: remove SSID code
git bisect bad 71c11fb57b924c160297ccd9e1761db598d00ac2
# good: [430cfe95a401baa0dc2022deaad02cb75d63c73c] iwl3945: remove dead code
git bisect good 430cfe95a401baa0dc2022deaad02cb75d63c73c