2.6.35-rc5+ WARNING at net/mac80211/scan.c:262

2.6.35-rc5+ WARNING at net/mac80211/scan.c:262

[Dominik Brodowski]

Hey,

Just saw this in dmesg:

[82970.511341] ------------[ cut here ]------------
[82970.511365] WARNING: at net/mac80211/scan.c:262 ieee80211_scan_completed+0x137/0x1d0()
[82970.511374] Hardware name: SQ45S70S
[82970.511380] Modules linked in: binfmt_misc rfcomm sco bnep l2cap af_packet cpufreq_powersave cpufreq_stats cpufreq_conservative cpufreq_userspace iwl3945 pcmcia iwlcore yenta_socket coretemp ohci1394 sbp2 sg ieee1394 pcmcia_rsrc uvcvideo pcmcia_core btusb joydev evdev
[82970.511470] Pid: 4382, comm: iwl3945 Not tainted 2.6.35-rc5+ #252
[82970.511477] Call Trace:
[82970.511494]  [<ffffffff81073aca>] warn_slowpath_common+0x7a/0xb0
[82970.511505]  [<ffffffff81073b15>] warn_slowpath_null+0x15/0x20
[82970.511516]  [<ffffffff81649ba7>] ieee80211_scan_completed+0x137/0x1d0
[82970.511544]  [<ffffffffa00e2d7e>] iwl_bg_scan_completed+0xbe/0xc0 [iwlcore]
[82970.511565]  [<ffffffffa00e2cc0>] ? iwl_bg_scan_completed+0x0/0xc0 [iwlcore]
[82970.511579]  [<ffffffff810892bc>] worker_thread+0x20c/0x380
[82970.511590]  [<ffffffff8108926a>] ? worker_thread+0x1ba/0x380
[82970.511603]  [<ffffffff8108e130>] ? autoremove_wake_function+0x0/0x40
[82970.511615]  [<ffffffff810890b0>] ? worker_thread+0x0/0x380
[82970.511625]  [<ffffffff8108dc9e>] kthread+0xae/0xc0
[82970.511639]  [<ffffffff8102c864>] kernel_thread_helper+0x4/0x10
[82970.511651]  [<ffffffff81685954>] ? restore_args+0x0/0x30
[82970.511662]  [<ffffffff8108dbf0>] ? kthread+0x0/0xc0
[82970.511671]  [<ffffffff8102c860>] ? kernel_thread_helper+0x0/0x10
[82970.511679] ---[ end trace ba66a6fa61b5510c ]---

Best,
	Dominik

Re: 2.6.35-rc5+ WARNING at net/mac80211/scan.c:262

[Johannes Berg]

Hi,

> [82970.511341] ------------[ cut here ]------------
> [82970.511365] WARNING: at net/mac80211/scan.c:262 ieee80211_scan_completed+0x137/0x1d0()

You don't happen to have a way of reproducing this? I have been
suspecting races in this area, and came up with this patch to fix them,
but haven't really validated it yet:

http://johannes.sipsolutions.net/patches/kernel/all/LATEST/NNN-mac80211-hw-scan-locking.patch

johannes

Re: 2.6.35-rc5+ WARNING at net/mac80211/scan.c:262

[Dominik Brodowski]

> 
> > [82970.511341] ------------[ cut here ]------------
> > [82970.511365] WARNING: at net/mac80211/scan.c:262 ieee80211_scan_completed+0x137/0x1d0()
> 
> You don't happen to have a way of reproducing this? I have been
> suspecting races in this area, and came up with this patch to fix them,

No, but as it happened again today, I would be willing to test it out.

> but haven't really validated it yet:
>
> http://johannes.sipsolutions.net/patches/kernel/all/LATEST/NNN-mac80211-hw-scan-locking.patch

patching file drivers/net/wireless/iwlwifi/iwl-core.c
Hunk #1 succeeded at 2103 (offset 102 lines).
Hunk #2 FAILED at 2015.
Hunk #3 succeeded at 2120 (offset 97 lines).
1 out of 3 hunks FAILED -- saving rejects to file
drivers/net/wireless/iwlwifi/iwl-core.c.rej

:(

Best,
	Dominik

Re: 2.6.35-rc5+ WARNING at net/mac80211/scan.c:262

[Johannes Berg]

On Thu, 2010-07-22 at 15:40 +0200, Dominik Brodowski wrote:

> > http://johannes.sipsolutions.net/patches/kernel/all/LATEST/NNN-mac80211-hw-scan-locking.patch
> 
> patching file drivers/net/wireless/iwlwifi/iwl-core.c
> Hunk #1 succeeded at 2103 (offset 102 lines).
> Hunk #2 FAILED at 2015.
> Hunk #3 succeeded at 2120 (offset 97 lines).
> 1 out of 3 hunks FAILED -- saving rejects to file
> drivers/net/wireless/iwlwifi/iwl-core.c.rej

Oh, it's against wireless-testing, which apparently has some other mods
there. I'll have to see if any other patch needs to go into .35 too.

johannes

Re: 2.6.35-rc5+ WARNING at net/mac80211/scan.c:262

[Dominik Brodowski]

On Thu, Jul 22, 2010 at 04:07:58PM +0200, Johannes Berg wrote:
> On Thu, 2010-07-22 at 15:40 +0200, Dominik Brodowski wrote:
> 
> > > http://johannes.sipsolutions.net/patches/kernel/all/LATEST/NNN-mac80211-hw-scan-locking.patch
> > 
> > patching file drivers/net/wireless/iwlwifi/iwl-core.c
> > Hunk #1 succeeded at 2103 (offset 102 lines).
> > Hunk #2 FAILED at 2015.
> > Hunk #3 succeeded at 2120 (offset 97 lines).
> > 1 out of 3 hunks FAILED -- saving rejects to file
> > drivers/net/wireless/iwlwifi/iwl-core.c.rej
> 
> Oh, it's against wireless-testing, which apparently has some other mods
> there. I'll have to see if any other patch needs to go into .35 too.

That's fine, I'll just test wireless-testing plus your patch from now on ;)

Best,
	Dominik

Re: 2.6.35-rc5+ WARNING at net/mac80211/scan.c:262

[Johannes Berg]

On Fri, 2010-07-23 at 10:27 +0200, Dominik Brodowski wrote:
> On Thu, Jul 22, 2010 at 04:07:58PM +0200, Johannes Berg wrote:
> > On Thu, 2010-07-22 at 15:40 +0200, Dominik Brodowski wrote:
> > 
> > > > http://johannes.sipsolutions.net/patches/kernel/all/LATEST/NNN-mac80211-hw-scan-locking.patch
> > > 
> > > patching file drivers/net/wireless/iwlwifi/iwl-core.c
> > > Hunk #1 succeeded at 2103 (offset 102 lines).
> > > Hunk #2 FAILED at 2015.
> > > Hunk #3 succeeded at 2120 (offset 97 lines).
> > > 1 out of 3 hunks FAILED -- saving rejects to file
> > > drivers/net/wireless/iwlwifi/iwl-core.c.rej
> > 
> > Oh, it's against wireless-testing, which apparently has some other mods
> > there. I'll have to see if any other patch needs to go into .35 too.
> 
> That's fine, I'll just test wireless-testing plus your patch from now on ;)

Hah, ok, I made a note to backport the patch for you, guess I'll delete
it. Wouldn't have gotten around to it today anyway I think.

johannes

Re: 2.6.35-rc5+ WARNING at net/mac80211/scan.c:262

[Dominik Brodowski]

Hey,

On Fri, Jul 23, 2010 at 10:33:10AM +0200, Johannes Berg wrote:
> > > Oh, it's against wireless-testing, which apparently has some other mods
> > > there. I'll have to see if any other patch needs to go into .35 too.
> > 
> > That's fine, I'll just test wireless-testing plus your patch from now on ;)
> 
> Hah, ok, I made a note to backport the patch for you, guess I'll delete
> it. Wouldn't have gotten around to it today anyway I think.

the problem didn't reappear when using wireless-testing plus your patch. As
I can't reproduce it -- it just happened every once in a while (maybe once a
day?) -- this doesn't necessarily mean the bug is fixed, but...

Best,
	Dominik

Re: 2.6.35-rc5+ WARNING at net/mac80211/scan.c:262

[Johannes Berg]

On Mon, 2010-07-26 at 10:17 +0200, Dominik Brodowski wrote:
> Hey,
> 
> On Fri, Jul 23, 2010 at 10:33:10AM +0200, Johannes Berg wrote:
> > > > Oh, it's against wireless-testing, which apparently has some other mods
> > > > there. I'll have to see if any other patch needs to go into .35 too.
> > > 
> > > That's fine, I'll just test wireless-testing plus your patch from now on ;)
> > 
> > Hah, ok, I made a note to backport the patch for you, guess I'll delete
> > it. Wouldn't have gotten around to it today anyway I think.
> 
> the problem didn't reappear when using wireless-testing plus your patch. As
> I can't reproduce it -- it just happened every once in a while (maybe once a
> day?) -- this doesn't necessarily mean the bug is fixed, but...

Alright, thanks. I don't suppose you tried wireless-testing w/o the
patch?

johannes

Re: 2.6.35-rc5+ WARNING at net/mac80211/scan.c:262

[Dominik Brodowski]

On Mon, Jul 26, 2010 at 10:21:38AM +0200, Johannes Berg wrote:
> On Mon, 2010-07-26 at 10:17 +0200, Dominik Brodowski wrote:
> > Hey,
> > 
> > On Fri, Jul 23, 2010 at 10:33:10AM +0200, Johannes Berg wrote:
> > > > > Oh, it's against wireless-testing, which apparently has some other mods
> > > > > there. I'll have to see if any other patch needs to go into .35 too.
> > > > 
> > > > That's fine, I'll just test wireless-testing plus your patch from now on ;)
> > > 
> > > Hah, ok, I made a note to backport the patch for you, guess I'll delete
> > > it. Wouldn't have gotten around to it today anyway I think.
> > 
> > the problem didn't reappear when using wireless-testing plus your patch. As
> > I can't reproduce it -- it just happened every once in a while (maybe once a
> > day?) -- this doesn't necessarily mean the bug is fixed, but...
> 
> Alright, thanks. I don't suppose you tried wireless-testing w/o the
> patch?

No. Shall I?

Best,
	Dominik

Re: 2.6.35-rc5+ WARNING at net/mac80211/scan.c:262

[Johannes Berg]

On Mon, 2010-07-26 at 10:27 +0200, Dominik Brodowski wrote:

> > > the problem didn't reappear when using wireless-testing plus your patch. As
> > > I can't reproduce it -- it just happened every once in a while (maybe once a
> > > day?) -- this doesn't necessarily mean the bug is fixed, but...
> > 
> > Alright, thanks. I don't suppose you tried wireless-testing w/o the
> > patch?
> 
> No. Shall I?

Well, I'd be interested in whether or not my patch fixed it, but I think
I'll push it upstream anyway.

johannes