Re: kernel 3.2.1: BUG: scheduling while atomic: swapper/0/0/0x10000100

[Stanislaw Gruszka <sgruszka@redhat.com>]

On Thu, Jan 26, 2012 at 10:49:47AM +0100, Arend van Spriel wrote:
> >>> backtrace:
> >>> :BUG: sleeping function called from invalid context at
> >>> drivers/base/power/runtime.c:785
> >>> :in_atomic(): 1, irqs_disabled(): 0, pid: 0, name: swapper/0
> >>> :1 lock held by swapper/0/0:
> >>> : #0:  (&chip->rts51x_suspend_timer){+.-...}, at: [<ffffffff8108d711>]
> >>> run_timer_softirq+0x111/0x600
> >>> :Pid: 0, comm: swapper/0 Tainted: G        W    3.2.0-2.fc17.x86_64.debug #1
> >>> :Call Trace:
> >>> : <IRQ>  [<ffffffff8105ee7a>] __might_sleep+0x13a/0x1f0
> >>> : [<ffffffffa00180b0>] ? rts51x_modi_suspend_timer+0x50/0x50 [ums_realtek]
> >>> : [<ffffffff813fdee3>] __pm_runtime_idle+0xa3/0xb0
> >>> : [<ffffffffa00180b0>] ? rts51x_modi_suspend_timer+0x50/0x50 [ums_realtek]
> >>> : [<ffffffff8146ed30>] usb_autopm_put_interface+0x30/0x40
> >>
> >> This trace seems to indicate what is wrong. At least for this one user.
> >> The usb_autopm_put_interface() call seems result in a sleep and the
> >> rts51x_suspend_timer_fn is holding a lock. Below the code indicated in
> >> the trace.
> >>
> >> runtime.c:
> >> 768 /**
> >> 769  * __pm_runtime_idle - Entry point for runtime idle operations.
> >> 770  * @dev: Device to send idle notification for.
> >> 771  * @rpmflags: Flag bits.
> >> 772  *
> >> 773  * If the RPM_GET_PUT flag is set, decrement the device's usage
> >> count and
> >> 774  * return immediately if it is larger than zero.  Then carry out an idle
> >> 775  * notification, either synchronous or asynchronous.
> >> 776  *
> >> 777  * This routine may be called in atomic context if the RPM_ASYNC
> >> flag is set,
> >> 778  * or if pm_runtime_irq_safe() has been called.
> >> 779  */
> >> 780 int __pm_runtime_idle(struct device *dev, int rpmflags)
> >> 781 {
> >> 782         unsigned long flags;
> >> 783         int retval;
> >> 784
> >> 785         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
> >>
> >> This issue can either be caused in ums_realtek module or the usb autopm
> >> code. Have not looked into that.
> >>
> > 
> > Just a wild guess: it seems that we're affected using different HW
> > configs with different USB devices, so it would indicate that usb
> > autopm is the culprit.

Except Arend, all other users reporting that have ums_realtek, so they
hit that driver issue. I just posted ums_realtek fix.

Arend issue is different, it happens on different kernel version 3.3-rc1 vs 3.2.

Stanislaw