On Friday, October 25, 2013 11:51:40 AM Rafael J. Wysocki wrote:
> On Friday, October 25, 2013 11:28:02 AM Rafael J. Wysocki wrote:
> > On Friday, October 25, 2013 10:02:22 AM Linus Torvalds wrote:
> > > Adding more people, so quoting the whole email for them.
> > >
> > > We definitely have some module unload issues. Guys, try the following
> > > a few times to unload modules:
> > >
> > > lsmod | grep ' 0 '| cut -d' ' -f1 | xargs sudo rmmod
> > >
> > > (a few times because unloading one module will then potentially make
> > > other modules unloadable).
> > >
> > > On my machine, I can trigger this, for example:
> > >
> > > ------------[ cut here ]------------
> > > WARNING: CPU: 0 PID: 3217 at fs/sysfs/file.c:498 sysfs_attr_ns+0x91/0xa0()
> > > sysfs: kobject (null) without dirent
> > > Modules linked in: fuse nf_conntrack_broadcast ipt_MASQUERADE ip6t_REJECT xt_$
> > > CPU: 0 PID: 3217 Comm: rmmod Not tainted 3.12.0-rc6-00284-ge6036c0b8896 #19
> > > Hardware name: Sony Corporation SVP11213CXB/VAIO, BIOS R0270V7 05/17/2013
> > > 0000000000000009 ffff8800aca35df8 ffffffff8160aab5 ffff8800aca35e40
> > > ffff8800aca35e30 ffffffff810514b8 ffffffffa013f080 ffff8801194a6040
> > > 0000000000000800 0000000000000000 0000000000c5b3e0 ffff8800aca35e90
> > > Call Trace:
> > > [<ffffffff8160aab5>] dump_stack+0x45/0x56
> > > [<ffffffff810514b8>] warn_slowpath_common+0x78/0xa0
> > > [<ffffffff81051527>] warn_slowpath_fmt+0x47/0x50
> > > [<ffffffff810b5960>] ? module_refcount+0xb0/0xb0
> > > [<ffffffff811e5c61>] sysfs_attr_ns+0x91/0xa0
> > > [<ffffffff811e5d2a>] sysfs_remove_file+0x1a/0x50
> > > [<ffffffff814c88a3>] cpufreq_sysfs_remove_file+0x13/0x30
> > > [<ffffffffa013d350>] acpi_cpufreq_exit+0x2e/0xcde [acpi_cpufreq]
> > > [<ffffffff810b7d1d>] SyS_delete_module+0x15d/0x2c0
> > > [<ffffffff81002929>] ? do_notify_resume+0x59/0x90
> > > [<ffffffff81618f62>] system_call_fastpath+0x16/0x1b
> > > ---[ end trace f887112caaa5c4ab ]---
> > >
> > > so at least we have a cpufreq/sysfs interaction bug. There may be others.
> > >
> > > This particular cpufreq issue may be triggered by the fact that
> > > acpi-cpufreq isn't actually in use (pstate is). Or it might be some
> > > generic cpufreq/sysfs bug. Rafael, Greg, ideas?
> >
> > I *think* that this indeed is related to acpi-cpufreq being unused. That said,
> > we've been fixing sysfs-related bugs in cpufreq recently and we may have
> > overlooked something.
> >
> > I'll have a deeper look at that.
>
> Well, if the ACPI cpufreq driver is not registered, the exit function of the
> module shouldn't try to unregister it, so I have the appended patch (untested)
> to fix that particular thing.
And in my opinion acpi_cpufreq_init() should just return an error code if it
can't register the driver, like in the (untested) patch below.
Rafael
---
drivers/cpufreq/acpi-cpufreq.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
Index: linux-pm/drivers/cpufreq/acpi-cpufreq.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/acpi-cpufreq.c
+++ linux-pm/drivers/cpufreq/acpi-cpufreq.c
@@ -988,10 +988,10 @@ static int __init acpi_cpufreq_init(void
/* don't keep reloading if cpufreq_driver exists */
if (cpufreq_get_current_driver())
- return 0;
+ return -EEXIST;
if (acpi_disabled)
- return 0;
+ return -ENODEV;
pr_debug("acpi_cpufreq_init\n");
--
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