* Oleg Nesterov <oleg@xxxxxxxxxx> wrote:
> On 11/11, KOSAKI Motohiro wrote:
> >
> > it seem simple ABBA lock, right?
> >
> > -> #4 (&dev->mutex){--..}:
> > [<c0160f87>] validate_chain+0x831/0xaa2
> > [<c0161872>] __lock_acquire+0x67a/0x6e0
> > [<c0161933>] lock_acquire+0x5b/0x81
> > [<c0a660e4>] mutex_lock_interruptible_nested+0xde/0x2f8
> > [<c0782d02>] input_register_handle+0x26/0x7a dev->mutex
> ^^^^^^^^^^
> > [<c04a62c9>] kbd_connect+0x64/0x8d
> > [<c0782842>] input_attach_handler+0x38/0x6b
> > [<c0784216>] input_register_handler+0x74/0xc3 input_mutex
> > [<c0f54e4b>] kbd_init+0x66/0x91
> > [<c0f54f7b>] vty_init+0xce/0xd7
> > [<c0f54952>] tty_init+0x193/0x197
> > [<c010112a>] do_one_initcall+0x42/0x133
> > [<c0f2d5cb>] kernel_init+0x16e/0x1d5
> > [<c0117c03>] kernel_thread_helper+0x7/0x10
> > [<ffffffff>] 0xffffffff
> >
> > -> #3 (input_mutex){--..}:
> > [<c0160f87>] validate_chain+0x831/0xaa2
> > [<c0161872>] __lock_acquire+0x67a/0x6e0
> > [<c0161933>] lock_acquire+0x5b/0x81
> > [<c0a660e4>] mutex_lock_interruptible_nested+0xde/0x2f8
> > [<c0783fbe>] input_register_device+0xff/0x17f input_mutex
> > [<c048a889>] acpi_button_add+0x31e/0x429
> > [<c04889f4>] acpi_device_probe+0x43/0xde
> > [<c052c67f>] driver_probe_device+0xa5/0x120
> > [<c052c73c>] __driver_attach+0x42/0x64 dev->sem
> ^^^^^^^^
> input_dev->mutex != device->sem
>
> > ...
> > [<c0f2d201>] do_async_initcalls+0x1a/0x2a
> > [<c0150eec>] run_workqueue+0xc3/0x193
> > [<c015195d>] worker_thread+0xbb/0xc7
> > [<c0153e2a>] kthread+0x40/0x66
>
> What is the kernel version, btw? I can't find do_async_initcalls
> in 2.6.27 or 2.6.28.
i suspect it's an older version of tip/master that still had async
initcalls.
> Anyway, this really looks like lockdep bug to me. Even if we really
> have the circular dependency (will try to grep more) I can't
> understand why lockdep claims that polldev_mutex depends on
> cpu_add_remove_lock.
ok, will re-report if i can trigger it again with latest kernels.
Rafael, please close this bug as cannot-reproduce for now.
Ingo
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