mbox series

[4.9.257,0/1] Bugfix for 781691c797de ("futex: Avoid violating the 10th rule of futex")

Message ID 20210222110542.3531596-1-zhengyejian1@huawei.com
Headers show
Series Bugfix for 781691c797de ("futex: Avoid violating the 10th rule of futex") | expand

Message

Zheng Yejian Feb. 22, 2021, 11:05 a.m. UTC 
This patch may fix the following bug:

Link:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/kernel/futex.c?h=linux-4.9.y&id=282aeb477a10d09cc5c4d73c54bb996964723f96

    > static int __fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
    > 				  struct task_struct *argowner)
    > {
    > 	struct futex_pi_state *pi_state = q->pi_state;
    > 	struct task_struct *oldowner, *newowner;
    > 	u32 uval, curval, newval, newtid;
    > 	int err = 0;
    > 
    > 	oldowner = pi_state->owner;
    > 
    > 	/* Owner died? */
    > 	if (!pi_state->owner)
    > 		newtid |= FUTEX_OWNER_DIED;
Variable "newtid" is used without initialized.

Peter Zijlstra (1):
  futex: Fix OWNER_DEAD fixup

 kernel/futex.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

Comments

Lee Jones Feb. 22, 2021, 11:54 a.m. UTC | #1 
On Mon, 22 Feb 2021, Zheng Yejian wrote:

> From: Peter Zijlstra <peterz@infradead.org>
> 
> commit a97cb0e7b3f4c6297fd857055ae8e895f402f501 upstream.
> 
> Both Geert and DaveJ reported that the recent futex commit:
> 
>   c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex")
> 
> introduced a problem with setting OWNER_DEAD. We set the bit on an
> uninitialized variable and then entirely optimize it away as a
> dead-store.
> 
> Move the setting of the bit to where it is more useful.
> 
> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
> Reported-by: Dave Jones <davej@codemonkey.org.uk>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Cc: Paul E. McKenney <paulmck@us.ibm.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Fixes: c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex")
> Link: http://lkml.kernel.org/r/20180122103947.GD2228@hirez.programming.kicks-ass.net
> Signed-off-by: Ingo Molnar <mingo@kernel.org>
> Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
> ---
>  kernel/futex.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)

Reviewed-by: Lee Jones <lee.jones@linaro.org>
Greg KH Feb. 22, 2021, 12:07 p.m. UTC | #2 
On Mon, Feb 22, 2021 at 11:54:24AM +0000, Lee Jones wrote:
> On Mon, 22 Feb 2021, Zheng Yejian wrote:
> 
> > From: Peter Zijlstra <peterz@infradead.org>
> > 
> > commit a97cb0e7b3f4c6297fd857055ae8e895f402f501 upstream.
> > 
> > Both Geert and DaveJ reported that the recent futex commit:
> > 
> >   c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex")
> > 
> > introduced a problem with setting OWNER_DEAD. We set the bit on an
> > uninitialized variable and then entirely optimize it away as a
> > dead-store.
> > 
> > Move the setting of the bit to where it is more useful.
> > 
> > Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
> > Reported-by: Dave Jones <davej@codemonkey.org.uk>
> > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> > Cc: Andrew Morton <akpm@linux-foundation.org>
> > Cc: Linus Torvalds <torvalds@linux-foundation.org>
> > Cc: Paul E. McKenney <paulmck@us.ibm.com>
> > Cc: Peter Zijlstra <peterz@infradead.org>
> > Cc: Thomas Gleixner <tglx@linutronix.de>
> > Fixes: c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex")
> > Link: http://lkml.kernel.org/r/20180122103947.GD2228@hirez.programming.kicks-ass.net
> > Signed-off-by: Ingo Molnar <mingo@kernel.org>
> > Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
> > ---
> >  kernel/futex.c | 7 +++----
> >  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> Reviewed-by: Lee Jones <lee.jones@linaro.org>

This does not apply to the 4.9.y tree at all right now, are you all sure
you got the backport correct?

confused,

greg k-h
Zheng Yejian Feb. 22, 2021, 12:20 p.m. UTC | #3 
On 2021/2/22 20:07, Greg KH wrote:
> On Mon, Feb 22, 2021 at 11:54:24AM +0000, Lee Jones wrote:
>> On Mon, 22 Feb 2021, Zheng Yejian wrote:
>>
>>> From: Peter Zijlstra <peterz@infradead.org>
>>>
>>> commit a97cb0e7b3f4c6297fd857055ae8e895f402f501 upstream.
>>>
>>> Both Geert and DaveJ reported that the recent futex commit:
>>>
>>>    c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex")
>>>
>>> introduced a problem with setting OWNER_DEAD. We set the bit on an
>>> uninitialized variable and then entirely optimize it away as a
>>> dead-store.
>>>
>>> Move the setting of the bit to where it is more useful.
>>>
>>> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
>>> Reported-by: Dave Jones <davej@codemonkey.org.uk>
>>> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
>>> Cc: Andrew Morton <akpm@linux-foundation.org>
>>> Cc: Linus Torvalds <torvalds@linux-foundation.org>
>>> Cc: Paul E. McKenney <paulmck@us.ibm.com>
>>> Cc: Peter Zijlstra <peterz@infradead.org>
>>> Cc: Thomas Gleixner <tglx@linutronix.de>
>>> Fixes: c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex")
>>> Link: http://lkml.kernel.org/r/20180122103947.GD2228@hirez.programming.kicks-ass.net
>>> Signed-off-by: Ingo Molnar <mingo@kernel.org>
>>> Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
>>> ---
>>>   kernel/futex.c | 7 +++----
>>>   1 file changed, 3 insertions(+), 4 deletions(-)
>>
>> Reviewed-by: Lee Jones <lee.jones@linaro.org>
> 
> This does not apply to the 4.9.y tree at all right now, are you all sure
> you got the backport correct?
> 
> confused,
> 
> greg k-h
> .
> 
I make the patch basing on 282aeb477a10 ("Linux 4.9.257").
Should I base on f0cf73f13b39 ("Linux 4.9.258-rc1")?
Greg KH Feb. 23, 2021, 1 p.m. UTC | #4 
On Mon, Feb 22, 2021 at 09:11:43PM +0800, Zhengyejian (Zetta) wrote:
> 

> 

> On 2021/2/22 20:36, Greg KH wrote:

> > On Mon, Feb 22, 2021 at 08:20:38PM +0800, Zhengyejian (Zetta) wrote:

> > > 

> > > 

> > > On 2021/2/22 20:07, Greg KH wrote:

> > > > On Mon, Feb 22, 2021 at 11:54:24AM +0000, Lee Jones wrote:

> > > > > On Mon, 22 Feb 2021, Zheng Yejian wrote:

> > > > > 

> > > > > > From: Peter Zijlstra <peterz@infradead.org>

> > > > > > 

> > > > > > commit a97cb0e7b3f4c6297fd857055ae8e895f402f501 upstream.

> > > > > > 

> > > > > > Both Geert and DaveJ reported that the recent futex commit:

> > > > > > 

> > > > > >     c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex")

> > > > > > 

> > > > > > introduced a problem with setting OWNER_DEAD. We set the bit on an

> > > > > > uninitialized variable and then entirely optimize it away as a

> > > > > > dead-store.

> > > > > > 

> > > > > > Move the setting of the bit to where it is more useful.

> > > > > > 

> > > > > > Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>

> > > > > > Reported-by: Dave Jones <davej@codemonkey.org.uk>

> > > > > > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>

> > > > > > Cc: Andrew Morton <akpm@linux-foundation.org>

> > > > > > Cc: Linus Torvalds <torvalds@linux-foundation.org>

> > > > > > Cc: Paul E. McKenney <paulmck@us.ibm.com>

> > > > > > Cc: Peter Zijlstra <peterz@infradead.org>

> > > > > > Cc: Thomas Gleixner <tglx@linutronix.de>

> > > > > > Fixes: c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex")

> > > > > > Link: http://lkml.kernel.org/r/20180122103947.GD2228@hirez.programming.kicks-ass.net

> > > > > > Signed-off-by: Ingo Molnar <mingo@kernel.org>

> > > > > > Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>

> > > > > > ---

> > > > > >    kernel/futex.c | 7 +++----

> > > > > >    1 file changed, 3 insertions(+), 4 deletions(-)

> > > > > 

> > > > > Reviewed-by: Lee Jones <lee.jones@linaro.org>

> > > > 

> > > > This does not apply to the 4.9.y tree at all right now, are you all sure

> > > > you got the backport correct?

> > > > 

> > > > confused,

> > > > 

> > > > greg k-h

> > > > .

> > > > 

> > > I make the patch basing on 282aeb477a10 ("Linux 4.9.257").

> > > Should I base on f0cf73f13b39 ("Linux 4.9.258-rc1")?

> > 

> > Yes please as I think this is already there.

> > 

> > How about just waiting for the next release to come out, I will push out

> > the 4.4 and 4.9 -rc releases right now as well to give everyone a chance

> > to sync up properly.

> Ok, I will rebase this patch then.


Great, can you try 4.9.258?

thanks,

greg k-h
Zheng Yejian Feb. 23, 2021, 2:51 p.m. UTC | #5 
On 2021/2/23 21:00, Greg KH wrote:
> On Mon, Feb 22, 2021 at 09:11:43PM +0800, Zhengyejian (Zetta) wrote:

>>

>>

>> On 2021/2/22 20:36, Greg KH wrote:

>>> On Mon, Feb 22, 2021 at 08:20:38PM +0800, Zhengyejian (Zetta) wrote:

>>>>

>>>>

>>>> On 2021/2/22 20:07, Greg KH wrote:

>>>>> On Mon, Feb 22, 2021 at 11:54:24AM +0000, Lee Jones wrote:

>>>>>> On Mon, 22 Feb 2021, Zheng Yejian wrote:

>>>>>>

>>>>>>> From: Peter Zijlstra <peterz@infradead.org>

>>>>>>>

>>>>>>> commit a97cb0e7b3f4c6297fd857055ae8e895f402f501 upstream.

>>>>>>>

>>>>>>> Both Geert and DaveJ reported that the recent futex commit:

>>>>>>>

>>>>>>>      c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex")

>>>>>>>

>>>>>>> introduced a problem with setting OWNER_DEAD. We set the bit on an

>>>>>>> uninitialized variable and then entirely optimize it away as a

>>>>>>> dead-store.

>>>>>>>

>>>>>>> Move the setting of the bit to where it is more useful.

>>>>>>>

>>>>>>> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>

>>>>>>> Reported-by: Dave Jones <davej@codemonkey.org.uk>

>>>>>>> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>

>>>>>>> Cc: Andrew Morton <akpm@linux-foundation.org>

>>>>>>> Cc: Linus Torvalds <torvalds@linux-foundation.org>

>>>>>>> Cc: Paul E. McKenney <paulmck@us.ibm.com>

>>>>>>> Cc: Peter Zijlstra <peterz@infradead.org>

>>>>>>> Cc: Thomas Gleixner <tglx@linutronix.de>

>>>>>>> Fixes: c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex")

>>>>>>> Link: http://lkml.kernel.org/r/20180122103947.GD2228@hirez.programming.kicks-ass.net

>>>>>>> Signed-off-by: Ingo Molnar <mingo@kernel.org>

>>>>>>> Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>

>>>>>>> ---

>>>>>>>     kernel/futex.c | 7 +++----

>>>>>>>     1 file changed, 3 insertions(+), 4 deletions(-)

>>>>>>

>>>>>> Reviewed-by: Lee Jones <lee.jones@linaro.org>

>>>>>

>>>>> This does not apply to the 4.9.y tree at all right now, are you all sure

>>>>> you got the backport correct?

>>>>>

>>>>> confused,

>>>>>

>>>>> greg k-h

>>>>> .

>>>>>

>>>> I make the patch basing on 282aeb477a10 ("Linux 4.9.257").

>>>> Should I base on f0cf73f13b39 ("Linux 4.9.258-rc1")?

>>>

>>> Yes please as I think this is already there.

>>>

>>> How about just waiting for the next release to come out, I will push out

>>> the 4.4 and 4.9 -rc releases right now as well to give everyone a chance

>>> to sync up properly.

>> Ok, I will rebase this patch then.

> 

> Great, can you try 4.9.258?


I'm very glad to.
Rebased patch is ready:
 
https://lore.kernel.org/lkml/20210223144151.916675-1-zhengyejian1@huawei.com/

Zheng Yejian