linux-kernel - Re: pcim_enable_device BUGs for libata devices in 2.6.20-git6

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20070212205444.GC18101@elf.ucw.cz>
Date:	Mon, 12 Feb 2007 21:54:44 +0100
From:	Pavel Machek <pavel@....cz>
To:	Tejun Heo <htejun@...il.com>
Cc:	Robert Hancock <hancockr@...w.ca>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	linux-ide@...r.kernel.org
Subject: Re: pcim_enable_device BUGs for libata devices in 2.6.20-git6

Hi!

> >I'm seeing BUGs like these on all libata-driven controllers when 
> >suspending to disk on 2.6.20-git6:
> >
> >sata_nv 0000:00:07.0: resuming
> >BUG: at drivers/pci/pci.c:817 pcim_enable_device()
> >
> >Call Trace:
> > [<ffffffff80337d21>] pcim_enable_device+0x8a/0xa5
> > [<ffffffff88099d18>] :libata:ata_pci_device_do_resume+0x20/0x59
> > [<ffffffff880bb731>] :sata_nv:nv_pci_device_resume+0x1d/0x100
> > [<ffffffff8039d2bf>] resume_device+0xcb/0x12c
> > [<ffffffff8039d3ac>] dpm_resume+0x8c/0xec
> > [<ffffffff8039d456>] device_resume+0x4a/0x5d
> > [<ffffffff802a0a33>] pm_suspend_disk+0x160/0x170
> > [<ffffffff8029f4b6>] enter_state+0x52/0x1da
> > [<ffffffff8029f69c>] state_store+0x5e/0x79
> > [<ffffffff802f2b20>] sysfs_write_file+0xe4/0x118
> > [<ffffffff80214b58>] vfs_write+0xce/0x177
> > [<ffffffff8021553e>] sys_write+0x45/0x6e
> > [<ffffffff8025711e>] system_call+0x7e/0x83
> >
> >It looks like what's happening is that during the "freezing" stage, we 
> >suspend and then resume the controllers. ata_pci_device_do_suspend only 
> >calls pci_disable_device if the event is PM_EVENT_SUSPEND but 
> >ata_pci_device_do_resume calls pcim_enable_device unconditionally. If 
> >the event was something else, then pcim_enable_device complains because 
> >the device was previously enabled and never disabled.
> >
> >Not sure what the best way to fix this is?
> 
> I think what should happen is either one of the followings.
> 
> 1. Don't restore power state and re-enable PCI device on resume from 
> freeze just as we don't do the opposite when freezing.
> 
> 2. Unconditionally disable and power down PCI device on suspend whether 
> it's freeze or not.
> 
> #2 would be simpler but I'm a bit worried about it.  There might be 
> controllers which choke after such sequence (save state, disable, power 
> down, no actual power removal, power on, restore state, re-enable).

I'd just go for #2.

> #1 can be easily done by taking a look at the current device power state 
> (gendev->power.power_state).  The problem is that no one in 
> suspend/resume path seems to be setting that variable except for
> runtime 

No, that variable is probably going to go away. If you want to
remember that you are resuming from freeze, just store that info in
private data structure.
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/