Re: Suspend to RAM regression in 2.6.28-rc2 (bisected)

["Carlos R. Mafra" <crmafra2@gmail.com>]

On Mon 27.Oct'08 at 22:07:42 +0100, Rafael J. Wysocki wrote:
> On Monday, 27 of October 2008, Carlos R. Mafra wrote:
> > On Mon 27.Oct'08 at 21:51:00 +0100, Rafael J. Wysocki wrote:
> > > On Monday, 27 of October 2008, Carlos R. Mafra wrote:
> > > > On Mon 27.Oct'08 at 20:13:43 +0100, Johannes Berg wrote:
> > > > > On Mon, 2008-10-27 at 20:11 +0100, Carlos R. Mafra wrote:
> > > > > 
> > > > > > > Do you get any kernel messages output? If you do, could you put messages
> > > > > > > into each line of ieee80211_set_disassoc to see where it hangs?
> > > > > > 
> > > > > > No messages appear, just a black screen.
> > > > > > 
> > > > > > But I can use the SysRq keys, and when I umount the
> > > > > > screen shows the message that umount succeed. I also tried SysRq+t but
> > > > > > the messages appear to fast to read.
> > > > > 
> > > > > Ok, but that means you _can_ get messages, it would help a lot if you
> > > > > could put a few printks into the set_disassoc function before/after each
> > > > > other function call, so we know where exactly it hangs. Pretty much all
> > > > > of them could possibly hang if there is some sort of locking error
> > > > > happening or anything relies on userspace to be running...
> > > > 
> > > > Ok, I humbly tried to do that with the patch at the end of the email,
> > > > but I did not appear to hang in this function tough.
> > > > 
> > > > Somehow I could get some messages printed when it was a black screen
> > > > before (I think it has to do with the debug level I set with SysRq...)
> > > > and I could see all the printks I've put there. 
> > > > 
> > > > The good thing is that I could get the complete syslog of the boot until 
> > > > the it failed after suspending to RAM (in 2.6.28-rc2 with my debug patch
> > > > below applied). The last messages before the laptop become unresponsive
> > > > (except for the SysRq) were these ones:
> > > > 
> > > > Oct 27 21:03:06 localhost kernel: Registered led device: iwl-phy0:radio
> > > > Oct 27 21:03:06 localhost kernel: Registered led device: iwl-phy0:assoc
> > > > Oct 27 21:03:06 localhost kernel: Registered led device: iwl-phy0:RX
> > > > Oct 27 21:03:06 localhost kernel: Registered led device: iwl-phy0:TX
> > > > Oct 27 21:03:06 localhost kernel: before rcu_read_lock
> > > > Oct 27 21:03:06 localhost kernel: before netif_tx_stop_all_queues
> > > > Oct 27 21:03:06 localhost kernel: before netif_carrier_off
> > > > Oct 27 21:03:06 localhost kernel: before ieee80211_sta
> > > > Oct 27 21:03:06 localhost kernel: inside sef_disconnected 1
> > > > Oct 27 21:03:06 localhost kernel: before ieee8021_led_assoc
> > > > Oct 27 21:03:06 localhost kernel: before ieee8021_sta_send_apinfo
> > > > Oct 27 21:03:06 localhost kernel: before sta_info_unlink
> > > > Oct 27 21:03:06 localhost kernel: before rcu_read_unlock
> > > > Oct 27 21:03:06 localhost kernel: before sta_info_destroy
> > > > Oct 27 21:03:06 localhost kernel: sd 0:0:0:0: [sda] Starting disk
> > > > Oct 27 21:03:06 localhost kernel: ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
> > > > Oct 27 21:03:06 localhost kernel: ata1.00: ACPI cmd ef/90:03:00:00:00:a0 succeeded
> > > > Oct 27 21:03:06 localhost kernel: ata1.00: ACPI cmd f5/00:00:00:00:00:a0 filtered out
> > > > Oct 27 21:03:06 localhost kernel: ata1.00: ACPI cmd ef/90:03:00:00:00:a0 succeeded
> > > > Oct 27 21:03:06 localhost kernel: ata1.00: ACPI cmd f5/00:00:00:00:00:a0 filtered out
> > > > Oct 27 21:03:06 localhost kernel: ata1.00: configured for UDMA/100
> > > > Oct 27 21:03:06 localhost kernel: ata1: exception Emask 0x10 SAct 0x0 SErr 0x0 action 0x9 t4
> > > > Oct 27 21:03:06 localhost kernel: ata1: irq_stat 0x00000040, connection status changed
> > > > Oct 27 21:03:06 localhost kernel: ata1: hard resetting link
> > > > Oct 27 21:03:06 localhost kernel: ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
> > > > Oct 27 21:03:06 localhost kernel: ata1.00: ACPI cmd ef/90:03:00:00:00:a0 succeeded
> > > > Oct 27 21:03:06 localhost kernel: ata1.00: ACPI cmd f5/00:00:00:00:00:a0 filtered out
> > > > Oct 27 21:03:06 localhost kernel: ata1.00: ACPI cmd ef/90:03:00:00:00:a0 succeeded
> > > > Oct 27 21:03:06 localhost kernel: ata1.00: ACPI cmd f5/00:00:00:00:00:a0 filtered out
> > > > Oct 27 21:03:06 localhost kernel: ata1.00: configured for UDMA/100
> > > > Oct 27 21:03:06 localhost kernel: ata1: EH complete
> > > > Oct 27 21:03:06 localhost kernel: sd 0:0:0:0: [sda] 488397168 512-byte hardware sectors: (250 GB/232 GiB)
> > > > Oct 27 21:03:06 localhost kernel: sd 0:0:0:0: [sda] Write Protect is off
> > > > Oct 27 21:03:06 localhost kernel: sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00
> > > > Oct 27 21:03:06 localhost kernel: sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
> > > > Oct 27 21:03:06 localhost kernel: sd 0:0:0:0: [sda] 488397168 512-byte hardware sectors: (250 GB/232 GiB)
> > > > Oct 27 21:03:06 localhost kernel: sd 0:0:0:0: [sda] Write Protect is off
> > > > Oct 27 21:03:06 localhost kernel: sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00
> > > > Oct 27 21:03:06 localhost kernel: sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
> > > > Oct 27 21:03:06 localhost kernel: Restarting tasks ... done.
> > > > Oct 27 21:03:07 localhost ifplugd(wlan0)[3182]: Link beat lost.
> > > > Oct 27 21:03:13 localhost ifplugd(wlan0)[3182]: Executing '/etc/ifplugd/ifplugd.action wlan0 down'.
> > > > Oct 27 21:06:20 localhost kernel: SysRq : Changing Loglevel
> > > > Oct 27 21:06:20 localhost kernel: Loglevel set to 4
> > > > Oct 27 21:06:22 localhost kernel: SysRq : Changing Loglevel
> > > > Oct 27 21:06:22 localhost kernel: Loglevel set to 6
> > > > Oct 27 21:06:32 localhost kernel: ffff80251670>] ? autoremove_wake_function+0x0/0x40
> > > > Oct 27 21:06:32 localhost kernel:  [<ffffffff8024e200>] ? worker_thread+0x0/0x110
> > > > Oct 27 21:06:32 localhost kernel:  [<ffffffff8025119d>] kthread+0x4d/0x80
> > > > Oct 27 21:06:32 localhost kernel:  [<ffffffff8020d1b9>] child_rip+0xa/0x11
> > > > 
> > > > and I have the complete trace also. I can try to put it somewhere in the web if it helps
> > > > (I already tried it, but I am new at the institute here and I could not set up my
> > > > webpage yet :-(
> > > 
> > > Please attach it to http://bugzilla.kernel.org/show_bug.cgi?id=11845 .
> > 
> > Done.
> 
> Hmm, this looks like a result of playing with the magic SysRq.  Did you try to
> press SysRq-something when the box became unresponsive?

Yes, that long trace is the result of SysRq+t but I never managed to
understand its result :-(

This last hang was somewhat different because I could read the messages
up to the point where the laptop was unresponsive (see the time in the
log, I waited 3 minutes until I decided to hit SysRq+t). I am not
sure why this happened, tough. 

All the other hangs were with a complete black screen. _But_ if I used
some SysRq combination during the time the screen was black
I could see the result in the screen. I know this because when the resume
failed I always used to sync+umount+reboot using the SysRq, and those messages
from the SysRq I could read ("Emergency Sync", "Emergency umount" or something
like that).

Ok, now I see I have another patch to test from Tomas...will try that.