[PATCH] virtio_console: Don't access uninitialized data.

[PATCH] virtio_console: Don't access uninitialized data.

[sjur.brandeland]

From: Sjur Brændeland <sjur.brandeland@stericsson.com>

Don't access uninitialized work-queue when removing device.
The work queue is initialized only if the device multi-queue.
So don't call cancel_work unless this is a multi-queue device.

This fixes the following panic:

Kernel panic - not syncing: BUG!
Call Trace:
62031b28:  [<6026085d>] panic+0x16b/0x2d3
62031b30:  [<6004ef5e>] flush_work+0x0/0x1d7
62031b60:  [<602606f2>] panic+0x0/0x2d3
62031b68:  [<600333b0>] memcpy+0x0/0x140
62031b80:  [<6002d58a>] unblock_signals+0x0/0x84
62031ba0:  [<602609c5>] printk+0x0/0xa0
62031bd8:  [<60264e51>] __mutex_unlock_slowpath+0x13d/0x148
62031c10:  [<6004ef5e>] flush_work+0x0/0x1d7
62031c18:  [<60050234>] try_to_grab_pending+0x0/0x17e
62031c38:  [<6004e984>] get_work_gcwq+0x71/0x8f
62031c48:  [<60050539>] __cancel_work_timer+0x5b/0x115
62031c78:  [<628acc85>] unplug_port+0x0/0x191 [virtio_console]
62031c98:  [<6005061c>] cancel_work_sync+0x12/0x14
62031ca8:  [<628ace96>] virtcons_remove+0x80/0x15c [virtio_console]
62031ce8:  [<628191de>] virtio_dev_remove+0x1e/0x7e [virtio]
62031d08:  [<601cf242>] __device_release_driver+0x75/0xe4
62031d28:  [<601cf2dd>] device_release_driver+0x2c/0x40
62031d48:  [<601ce0dd>] driver_unbind+0x7d/0xc6
62031d88:  [<601cd5d9>] drv_attr_store+0x27/0x29
62031d98:  [<60115f61>] sysfs_write_file+0x100/0x14d
62031df8:  [<600b737d>] vfs_write+0xcb/0x184
62031e08:  [<600b58b8>] filp_close+0x88/0x94
62031e38:  [<600b7686>] sys_write+0x59/0x88
62031e88:  [<6001ced1>] handle_syscall+0x5d/0x80
62031ea8:  [<60030a74>] userspace+0x405/0x531
62031f08:  [<600d32cc>] sys_dup+0x0/0x5e
62031f28:  [<601b11d6>] strcpy+0x0/0x18
62031f38:  [<600be46c>] do_execve+0x10/0x12
62031f48:  [<600184c7>] run_init_process+0x43/0x45
62031fd8:  [<60019a91>] new_thread_handler+0xba/0xbc

Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
---

This fix is intended of v3.8.

Thanks,
Sjur

 drivers/char/virtio_console.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 684b0d5..ee4dbea 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -2062,7 +2062,8 @@ static void virtcons_remove(struct virtio_device *vdev)
 	/* Disable interrupts for vqs */
 	vdev->config->reset(vdev);
 	/* Finish up work that's lined up */
-	cancel_work_sync(&portdev->control_work);
+	if (use_multiport(portdev))
+		cancel_work_sync(&portdev->control_work);
 
 	list_for_each_entry_safe(port, port2, &portdev->ports, list)
 		unplug_port(port);
-- 
1.7.5.4

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Re: [PATCH] virtio_console: Don't access uninitialized data.

[Rusty Russell]

sjur.brandeland@stericsson.com writes:
> From: Sjur Brændeland <sjur.brandeland@stericsson.com>
>
> Don't access uninitialized work-queue when removing device.
> The work queue is initialized only if the device multi-queue.
> So don't call cancel_work unless this is a multi-queue device.
>
> This fixes the following panic:

Thanks, applied.

Cheers,
Rusty.
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Re: [PATCH] virtio_console: Don't access uninitialized data.

[Amit Shah]

On (Thu) 17 Jan 2013 [13:21:32], sjur.brandeland@stericsson.com wrote:
> From: Sjur Brændeland <sjur.brandeland@stericsson.com>
> 
> Don't access uninitialized work-queue when removing device.
> The work queue is initialized only if the device multi-queue.
> So don't call cancel_work unless this is a multi-queue device.
> 
> This fixes the following panic:

[snip]

> Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>

Acked-by: Amit Shah <amit.shah@redhat.com>

> This fix is intended of v3.8.

Should also be CC'ed to stable@

Thanks,

		Amit

Re: [PATCH] virtio_console: Don't access uninitialized data.

[Rusty Russell]

Amit Shah <amit.shah@redhat.com> writes:
> On (Thu) 17 Jan 2013 [13:21:32], sjur.brandeland@stericsson.com wrote:
>> From: Sjur Brændeland <sjur.brandeland@stericsson.com>
>> 
>> Don't access uninitialized work-queue when removing device.
>> The work queue is initialized only if the device multi-queue.
>> So don't call cancel_work unless this is a multi-queue device.
>> 
>> This fixes the following panic:
>
> [snip]
>
>> Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
>
> Acked-by: Amit Shah <amit.shah@redhat.com>
>
>> This fix is intended of v3.8.
>
> Should also be CC'ed to stable@

Sorry, I was at linux.conf.au all last week.

I've already sent it to Linus.  Sjur said: "This fix is intended of
v3.8.".  If it needs to be in -stable, please tell me and I'll fwd it
manually.

Thanks,
Rusty.
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Re: [PATCH] virtio_console: Don't access uninitialized data.

[Amit Shah]

On (Mon) 04 Feb 2013 [10:09:05], Rusty Russell wrote:
> Amit Shah <amit.shah@redhat.com> writes:
> > On (Thu) 17 Jan 2013 [13:21:32], sjur.brandeland@stericsson.com wrote:
> >> From: Sjur Brændeland <sjur.brandeland@stericsson.com>
> >> 
> >> Don't access uninitialized work-queue when removing device.
> >> The work queue is initialized only if the device multi-queue.
> >> So don't call cancel_work unless this is a multi-queue device.
> >> 
> >> This fixes the following panic:
> >
> > [snip]
> >
> >> Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
> >
> > Acked-by: Amit Shah <amit.shah@redhat.com>
> >
> >> This fix is intended of v3.8.
> >
> > Should also be CC'ed to stable@
> 
> Sorry, I was at linux.conf.au all last week.
> 
> I've already sent it to Linus.  Sjur said: "This fix is intended of
> v3.8.".  If it needs to be in -stable, please tell me and I'll fwd it
> manually.

This can result in a panic when removing the device or module (when
not using multiport).  I'd vote for submitting to stable.

		Amit

Re: [PATCH] virtio_console: Don't access uninitialized data.

[Rusty Russell]

Amit Shah <amit.shah@redhat.com> writes:
> On (Mon) 04 Feb 2013 [10:09:05], Rusty Russell wrote:
>> Amit Shah <amit.shah@redhat.com> writes:
>> > On (Thu) 17 Jan 2013 [13:21:32], sjur.brandeland@stericsson.com wrote:
>> >> From: Sjur Brændeland <sjur.brandeland@stericsson.com>
>> >> 
>> >> Don't access uninitialized work-queue when removing device.
>> >> The work queue is initialized only if the device multi-queue.
>> >> So don't call cancel_work unless this is a multi-queue device.
>> >> 
>> >> This fixes the following panic:
>> >
>> > [snip]
>> >
>> >> Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
>> >
>> > Acked-by: Amit Shah <amit.shah@redhat.com>
>> >
>> >> This fix is intended of v3.8.
>> >
>> > Should also be CC'ed to stable@
...
>> I've already sent it to Linus.  Sjur said: "This fix is intended of
>> v3.8.".  If it needs to be in -stable, please tell me and I'll fwd it
>> manually.
>
> This can result in a panic when removing the device or module (when
> not using multiport).  I'd vote for submitting to stable.
>
> 		Amit

OK stable, please cherry-pick from Linus' tree:

commit b26ada9abe26290b1dcd06075935b977548c50db
Author: Sjur Brændeland <sjur.brandeland@stericsson.com>
Date:   Tue Jan 22 09:50:26 2013 +1030

    virtio_console: Don't access uninitialized data.

Thanks,
Rusty.
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Re: [PATCH] virtio_console: Don't access uninitialized data.

[Greg KH]

On Wed, Feb 06, 2013 at 10:38:36AM +1030, Rusty Russell wrote:
> Amit Shah <amit.shah@redhat.com> writes:
> > On (Mon) 04 Feb 2013 [10:09:05], Rusty Russell wrote:
> >> Amit Shah <amit.shah@redhat.com> writes:
> >> > On (Thu) 17 Jan 2013 [13:21:32], sjur.brandeland@stericsson.com wrote:
> >> >> From: Sjur Brændeland <sjur.brandeland@stericsson.com>
> >> >> 
> >> >> Don't access uninitialized work-queue when removing device.
> >> >> The work queue is initialized only if the device multi-queue.
> >> >> So don't call cancel_work unless this is a multi-queue device.
> >> >> 
> >> >> This fixes the following panic:
> >> >
> >> > [snip]
> >> >
> >> >> Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
> >> >
> >> > Acked-by: Amit Shah <amit.shah@redhat.com>
> >> >
> >> >> This fix is intended of v3.8.
> >> >
> >> > Should also be CC'ed to stable@
> ...
> >> I've already sent it to Linus.  Sjur said: "This fix is intended of
> >> v3.8.".  If it needs to be in -stable, please tell me and I'll fwd it
> >> manually.
> >
> > This can result in a panic when removing the device or module (when
> > not using multiport).  I'd vote for submitting to stable.
> >
> > 		Amit
> 
> OK stable, please cherry-pick from Linus' tree:
> 
> commit b26ada9abe26290b1dcd06075935b977548c50db
> Author: Sjur Brændeland <sjur.brandeland@stericsson.com>
> Date:   Tue Jan 22 09:50:26 2013 +1030
> 
>     virtio_console: Don't access uninitialized data.

 $ git show b26ada9abe26290b1dcd06075935b977548c50db
 fatal: bad object b26ada9abe26290b1dcd06075935b977548c50db

What am I missing here?

greg k-h

Re: [PATCH] virtio_console: Don't access uninitialized data.

[Wanlong Gao]

On 02/06/2013 09:40 AM, Greg KH wrote:
> On Wed, Feb 06, 2013 at 10:38:36AM +1030, Rusty Russell wrote:
>> Amit Shah <amit.shah@redhat.com> writes:
>>> On (Mon) 04 Feb 2013 [10:09:05], Rusty Russell wrote:
>>>> Amit Shah <amit.shah@redhat.com> writes:
>>>>> On (Thu) 17 Jan 2013 [13:21:32], sjur.brandeland@stericsson.com wrote:
>>>>>> From: Sjur Brændeland <sjur.brandeland@stericsson.com>
>>>>>>
>>>>>> Don't access uninitialized work-queue when removing device.
>>>>>> The work queue is initialized only if the device multi-queue.
>>>>>> So don't call cancel_work unless this is a multi-queue device.
>>>>>>
>>>>>> This fixes the following panic:
>>>>>
>>>>> [snip]
>>>>>
>>>>>> Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
>>>>>
>>>>> Acked-by: Amit Shah <amit.shah@redhat.com>
>>>>>
>>>>>> This fix is intended of v3.8.
>>>>>
>>>>> Should also be CC'ed to stable@
>> ...
>>>> I've already sent it to Linus.  Sjur said: "This fix is intended of
>>>> v3.8.".  If it needs to be in -stable, please tell me and I'll fwd it
>>>> manually.
>>>
>>> This can result in a panic when removing the device or module (when
>>> not using multiport).  I'd vote for submitting to stable.
>>>
>>> 		Amit
>>
>> OK stable, please cherry-pick from Linus' tree:
>>
>> commit b26ada9abe26290b1dcd06075935b977548c50db
>> Author: Sjur Brændeland <sjur.brandeland@stericsson.com>
>> Date:   Tue Jan 22 09:50:26 2013 +1030
>>
>>     virtio_console: Don't access uninitialized data.
> 
>  $ git show b26ada9abe26290b1dcd06075935b977548c50db
>  fatal: bad object b26ada9abe26290b1dcd06075935b977548c50db
> 
> What am I missing here?

It seems just in rusty's tree but not in linus' tree.
http://git.kernel.org/?p=linux/kernel/git/rusty/linux.git;a=commitdiff;h=b26ada9abe26290b1dcd06075935b977548c50db

Thanks,
Wanlong Gao

> 
> greg k-h
> _______________________________________________
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> https://lists.linuxfoundation.org/mailman/listinfo/virtualization
> 

Re: [PATCH] virtio_console: Don't access uninitialized data.

[Greg KH]

On Wed, Feb 06, 2013 at 10:14:59AM +0800, Wanlong Gao wrote:
> On 02/06/2013 09:40 AM, Greg KH wrote:
> > On Wed, Feb 06, 2013 at 10:38:36AM +1030, Rusty Russell wrote:
> >> Amit Shah <amit.shah@redhat.com> writes:
> >>> On (Mon) 04 Feb 2013 [10:09:05], Rusty Russell wrote:
> >>>> Amit Shah <amit.shah@redhat.com> writes:
> >>>>> On (Thu) 17 Jan 2013 [13:21:32], sjur.brandeland@stericsson.com wrote:
> >>>>>> From: Sjur Brændeland <sjur.brandeland@stericsson.com>
> >>>>>>
> >>>>>> Don't access uninitialized work-queue when removing device.
> >>>>>> The work queue is initialized only if the device multi-queue.
> >>>>>> So don't call cancel_work unless this is a multi-queue device.
> >>>>>>
> >>>>>> This fixes the following panic:
> >>>>>
> >>>>> [snip]
> >>>>>
> >>>>>> Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
> >>>>>
> >>>>> Acked-by: Amit Shah <amit.shah@redhat.com>
> >>>>>
> >>>>>> This fix is intended of v3.8.
> >>>>>
> >>>>> Should also be CC'ed to stable@
> >> ...
> >>>> I've already sent it to Linus.  Sjur said: "This fix is intended of
> >>>> v3.8.".  If it needs to be in -stable, please tell me and I'll fwd it
> >>>> manually.
> >>>
> >>> This can result in a panic when removing the device or module (when
> >>> not using multiport).  I'd vote for submitting to stable.
> >>>
> >>> 		Amit
> >>
> >> OK stable, please cherry-pick from Linus' tree:
> >>
> >> commit b26ada9abe26290b1dcd06075935b977548c50db
> >> Author: Sjur Brændeland <sjur.brandeland@stericsson.com>
> >> Date:   Tue Jan 22 09:50:26 2013 +1030
> >>
> >>     virtio_console: Don't access uninitialized data.
> > 
> >  $ git show b26ada9abe26290b1dcd06075935b977548c50db
> >  fatal: bad object b26ada9abe26290b1dcd06075935b977548c50db
> > 
> > What am I missing here?
> 
> It seems just in rusty's tree but not in linus' tree.
> http://git.kernel.org/?p=linux/kernel/git/rusty/linux.git;a=commitdiff;h=b26ada9abe26290b1dcd06075935b977548c50db

Sorry, I can't do anything with that, it needs to be in Linus's tree.
Please read Documentation/stable_kernel_rules.txt for the details.

If someone can resend this when it does get into Linus's tree, I'll be
glad to queue it up.

thanks,

greg k-h

Re: [PATCH] virtio_console: Don't access uninitialized data.

[Rusty Russell]

Greg KH <gregkh@linuxfoundation.org> writes:
> On Wed, Feb 06, 2013 at 10:38:36AM +1030, Rusty Russell wrote:
>> Amit Shah <amit.shah@redhat.com> writes:
>> > On (Mon) 04 Feb 2013 [10:09:05], Rusty Russell wrote:
>> >> Amit Shah <amit.shah@redhat.com> writes:
>> >> > On (Thu) 17 Jan 2013 [13:21:32], sjur.brandeland@stericsson.com wrote:
>> >> >> From: Sjur Brændeland <sjur.brandeland@stericsson.com>
>> >> >> 
>> >> >> Don't access uninitialized work-queue when removing device.
>> >> >> The work queue is initialized only if the device multi-queue.
>> >> >> So don't call cancel_work unless this is a multi-queue device.
>> >> >> 
>> >> >> This fixes the following panic:
>> >> >
>> >> > [snip]
>> >> >
>> >> >> Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
>> >> >
>> >> > Acked-by: Amit Shah <amit.shah@redhat.com>
>> >> >
>> >> >> This fix is intended of v3.8.
>> >> >
>> >> > Should also be CC'ed to stable@
>> ...
>> >> I've already sent it to Linus.  Sjur said: "This fix is intended of
>> >> v3.8.".  If it needs to be in -stable, please tell me and I'll fwd it
>> >> manually.
>> >
>> > This can result in a panic when removing the device or module (when
>> > not using multiport).  I'd vote for submitting to stable.
>> >
>> > 		Amit
>> 
>> OK stable, please cherry-pick from Linus' tree:
>> 
>> commit b26ada9abe26290b1dcd06075935b977548c50db
>> Author: Sjur Brændeland <sjur.brandeland@stericsson.com>
>> Date:   Tue Jan 22 09:50:26 2013 +1030
>> 
>>     virtio_console: Don't access uninitialized data.
>
>  $ git show b26ada9abe26290b1dcd06075935b977548c50db
>  fatal: bad object b26ada9abe26290b1dcd06075935b977548c50db
>
> What am I missing here?

My mistake, Linus has not pulled this.

I have added CC:stable, and will request now.

Sorry for the noise,
Rusty.
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