linux-kernel - Re: PM regression in next

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Date:   Fri, 12 Jan 2018 13:30:32 +0100
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Tony Lindgren <tony@...mide.com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Stephen Rothwell <sfr@...b.auug.org.au>,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-omap@...r.kernel.org, Linux PM <linux-pm@...r.kernel.org>
Subject: Re: PM regression in next

On Friday, January 12, 2018 1:23:54 PM CET Rafael J. Wysocki wrote:
> On Friday, January 12, 2018 2:32:57 AM CET Tony Lindgren wrote:
> > * Tony Lindgren <tony@...mide.com> [180111 17:20]:
> > > Well I tried to measure suspend power consumption and noticed
> > > that system suspend fails too hand hangs the network device:
> > > 
> > > # echo mem > /sys/power/state
> > > [   32.577850] PM: suspend entry (deep)
> > > [   32.582031] PM: Syncing filesystems ... done.
> > > [   32.598083] Freezing user space processes ... (elapsed 0.002 seconds) done.
> > > [   32.608398] OOM killer disabled.
> > > [   32.611846] Freezing remaining freezable tasks ... (elapsed 0.002 seconds) done.
> > > [   32.622192] Suspending console(s) (use no_console_suspend to debug)
> > > [   32.651123] dpm_run_callback(): mdio_bus_suspend+0x0/0x24 returns 4352
> > > [   32.651428] PM: Device 2c000000.ethernet-ffffffff:01 failed to suspend: error 4352
> 
> This looks totally bogus.
> 
> First, "error" should be a negative number and we print it as int.
> 
> Second, error codes are not in this range anyway.
> 
> > > [   32.653289] PM: Some devices failed to suspend, or early wake event detected
> > > [   32.685455] OOM killer enabled.
> > > [   32.688629] Restarting tasks ... done.
> > > [   32.695983] PM: suspend exit
> > > ash: write error: Bad address
> > > 
> > > That too works just fine at commit 70286688e5ad.
> > 
> > Suspend fails at commit e2d7fe89e8ae though, so looks like we
> > have two separate issues. I'll try to bisect that separately.

I guess what may happen is that something started to return positive numbers
which confuse things all over when passed along by its callers as error codes.

Thanks,
Rafael