* [PATCH] mm: memory_hotplug: fix memory error handling
@ 2022-05-30 5:33 Muchun Song
2022-05-30 6:55 ` David Hildenbrand
0 siblings, 1 reply; 5+ messages in thread
From: Muchun Song @ 2022-05-30 5:33 UTC (permalink / raw)
To: gregkh, rafael, david, cheloha, mhocko, akpm, nathanl
Cc: linux-kernel, Muchun Song, stable
The device_unregister() is supposed to be used to unregister devices if
device_register() has succeed. And device_unregister() will put device.
The caller should not do it again, otherwise, the first call of
put_device() will drop the last reference count, then the next call
of device_unregister() will UAF on device.
Fixes: 4fb6eabf1037 ("drivers/base/memory.c: cache memory blocks in xarray to accelerate lookup")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org>
---
drivers/base/memory.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 7222ff9b5e05..084d67fd55cc 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -636,10 +636,9 @@ static int __add_memory_block(struct memory_block *memory)
}
ret = xa_err(xa_store(&memory_blocks, memory->dev.id, memory,
GFP_KERNEL));
- if (ret) {
- put_device(&memory->dev);
+ if (ret)
device_unregister(&memory->dev);
- }
+
return ret;
}
--
2.11.0
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] mm: memory_hotplug: fix memory error handling
2022-05-30 5:33 [PATCH] mm: memory_hotplug: fix memory error handling Muchun Song
@ 2022-05-30 6:55 ` David Hildenbrand
2022-05-30 7:08 ` Muchun Song
0 siblings, 1 reply; 5+ messages in thread
From: David Hildenbrand @ 2022-05-30 6:55 UTC (permalink / raw)
To: Muchun Song, gregkh, rafael, cheloha, mhocko, akpm, nathanl
Cc: linux-kernel, stable
On 30.05.22 07:33, Muchun Song wrote:
> The device_unregister() is supposed to be used to unregister devices if
> device_register() has succeed. And device_unregister() will put device.
> The caller should not do it again, otherwise, the first call of
> put_device() will drop the last reference count, then the next call
> of device_unregister() will UAF on device.
>
> Fixes: 4fb6eabf1037 ("drivers/base/memory.c: cache memory blocks in xarray to accelerate lookup")
> Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> Cc: <stable@vger.kernel.org>
> ---
> drivers/base/memory.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/base/memory.c b/drivers/base/memory.c
> index 7222ff9b5e05..084d67fd55cc 100644
> --- a/drivers/base/memory.c
> +++ b/drivers/base/memory.c
> @@ -636,10 +636,9 @@ static int __add_memory_block(struct memory_block *memory)
> }
> ret = xa_err(xa_store(&memory_blocks, memory->dev.id, memory,
> GFP_KERNEL));
> - if (ret) {
> - put_device(&memory->dev);
> + if (ret)
> device_unregister(&memory->dev);
> - }
> +
> return ret;
> }
>
See
https://lkml.kernel.org/r/d44c63d78affe844f020dc02ad6af29abc448fc4.1650611702.git.christophe.jaillet@wanadoo.fr
--
Thanks,
David / dhildenb
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] mm: memory_hotplug: fix memory error handling
2022-05-30 6:55 ` David Hildenbrand
@ 2022-05-30 7:08 ` Muchun Song
2022-05-30 7:10 ` David Hildenbrand
0 siblings, 1 reply; 5+ messages in thread
From: Muchun Song @ 2022-05-30 7:08 UTC (permalink / raw)
To: David Hildenbrand
Cc: Greg KH, Rafael J. Wysocki, cheloha, Michal Hocko, Andrew Morton,
Nathan Lynch, LKML, linux- stable
On Mon, May 30, 2022 at 2:56 PM David Hildenbrand <david@redhat.com> wrote:
>
> On 30.05.22 07:33, Muchun Song wrote:
> > The device_unregister() is supposed to be used to unregister devices if
> > device_register() has succeed. And device_unregister() will put device.
> > The caller should not do it again, otherwise, the first call of
> > put_device() will drop the last reference count, then the next call
> > of device_unregister() will UAF on device.
> >
> > Fixes: 4fb6eabf1037 ("drivers/base/memory.c: cache memory blocks in xarray to accelerate lookup")
> > Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> > Cc: <stable@vger.kernel.org>
> > ---
> > drivers/base/memory.c | 5 ++---
> > 1 file changed, 2 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/base/memory.c b/drivers/base/memory.c
> > index 7222ff9b5e05..084d67fd55cc 100644
> > --- a/drivers/base/memory.c
> > +++ b/drivers/base/memory.c
> > @@ -636,10 +636,9 @@ static int __add_memory_block(struct memory_block *memory)
> > }
> > ret = xa_err(xa_store(&memory_blocks, memory->dev.id, memory,
> > GFP_KERNEL));
> > - if (ret) {
> > - put_device(&memory->dev);
> > + if (ret)
> > device_unregister(&memory->dev);
> > - }
> > +
> > return ret;
> > }
> >
>
> See
>
> https://lkml.kernel.org/r/d44c63d78affe844f020dc02ad6af29abc448fc4.1650611702.git.christophe.jaillet@wanadoo.fr
>
I see. Good job by Christophe. Thanks David.
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] mm: memory_hotplug: fix memory error handling
2022-05-30 7:08 ` Muchun Song
@ 2022-05-30 7:10 ` David Hildenbrand
2022-05-30 7:16 ` Muchun Song
0 siblings, 1 reply; 5+ messages in thread
From: David Hildenbrand @ 2022-05-30 7:10 UTC (permalink / raw)
To: Muchun Song
Cc: Greg KH, Rafael J. Wysocki, cheloha, Michal Hocko, Andrew Morton,
Nathan Lynch, LKML, linux- stable
On 30.05.22 09:08, Muchun Song wrote:
> On Mon, May 30, 2022 at 2:56 PM David Hildenbrand <david@redhat.com> wrote:
>>
>> On 30.05.22 07:33, Muchun Song wrote:
>>> The device_unregister() is supposed to be used to unregister devices if
>>> device_register() has succeed. And device_unregister() will put device.
>>> The caller should not do it again, otherwise, the first call of
>>> put_device() will drop the last reference count, then the next call
>>> of device_unregister() will UAF on device.
>>>
>>> Fixes: 4fb6eabf1037 ("drivers/base/memory.c: cache memory blocks in xarray to accelerate lookup")
>>> Signed-off-by: Muchun Song <songmuchun@bytedance.com>
>>> Cc: <stable@vger.kernel.org>
>>> ---
>>> drivers/base/memory.c | 5 ++---
>>> 1 file changed, 2 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/base/memory.c b/drivers/base/memory.c
>>> index 7222ff9b5e05..084d67fd55cc 100644
>>> --- a/drivers/base/memory.c
>>> +++ b/drivers/base/memory.c
>>> @@ -636,10 +636,9 @@ static int __add_memory_block(struct memory_block *memory)
>>> }
>>> ret = xa_err(xa_store(&memory_blocks, memory->dev.id, memory,
>>> GFP_KERNEL));
>>> - if (ret) {
>>> - put_device(&memory->dev);
>>> + if (ret)
>>> device_unregister(&memory->dev);
>>> - }
>>> +
>>> return ret;
>>> }
>>>
>>
>> See
>>
>> https://lkml.kernel.org/r/d44c63d78affe844f020dc02ad6af29abc448fc4.1650611702.git.christophe.jaillet@wanadoo.fr
>>
>
> I see. Good job by Christophe. Thanks David.
>
I'm curious how both of you found that issue? Just by staring at that
code? :)
--
Thanks,
David / dhildenb
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] mm: memory_hotplug: fix memory error handling
2022-05-30 7:10 ` David Hildenbrand
@ 2022-05-30 7:16 ` Muchun Song
0 siblings, 0 replies; 5+ messages in thread
From: Muchun Song @ 2022-05-30 7:16 UTC (permalink / raw)
To: David Hildenbrand
Cc: Greg KH, Rafael J. Wysocki, cheloha, Michal Hocko, Andrew Morton,
Nathan Lynch, LKML, linux- stable
On Mon, May 30, 2022 at 3:10 PM David Hildenbrand <david@redhat.com> wrote:
>
> On 30.05.22 09:08, Muchun Song wrote:
> > On Mon, May 30, 2022 at 2:56 PM David Hildenbrand <david@redhat.com> wrote:
> >>
> >> On 30.05.22 07:33, Muchun Song wrote:
> >>> The device_unregister() is supposed to be used to unregister devices if
> >>> device_register() has succeed. And device_unregister() will put device.
> >>> The caller should not do it again, otherwise, the first call of
> >>> put_device() will drop the last reference count, then the next call
> >>> of device_unregister() will UAF on device.
> >>>
> >>> Fixes: 4fb6eabf1037 ("drivers/base/memory.c: cache memory blocks in xarray to accelerate lookup")
> >>> Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> >>> Cc: <stable@vger.kernel.org>
> >>> ---
> >>> drivers/base/memory.c | 5 ++---
> >>> 1 file changed, 2 insertions(+), 3 deletions(-)
> >>>
> >>> diff --git a/drivers/base/memory.c b/drivers/base/memory.c
> >>> index 7222ff9b5e05..084d67fd55cc 100644
> >>> --- a/drivers/base/memory.c
> >>> +++ b/drivers/base/memory.c
> >>> @@ -636,10 +636,9 @@ static int __add_memory_block(struct memory_block *memory)
> >>> }
> >>> ret = xa_err(xa_store(&memory_blocks, memory->dev.id, memory,
> >>> GFP_KERNEL));
> >>> - if (ret) {
> >>> - put_device(&memory->dev);
> >>> + if (ret)
> >>> device_unregister(&memory->dev);
> >>> - }
> >>> +
> >>> return ret;
> >>> }
> >>>
> >>
> >> See
> >>
> >> https://lkml.kernel.org/r/d44c63d78affe844f020dc02ad6af29abc448fc4.1650611702.git.christophe.jaillet@wanadoo.fr
> >>
> >
> > I see. Good job by Christophe. Thanks David.
> >
>
> I'm curious how both of you found that issue? Just by staring at that
> code? :)
>
I am reading the code here today, then I saw it by chance.
No tricks :-).
THanks.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2022-05-30 7:17 UTC | newest]
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2022-05-30 5:33 [PATCH] mm: memory_hotplug: fix memory error handling Muchun Song
2022-05-30 6:55 ` David Hildenbrand
2022-05-30 7:08 ` Muchun Song
2022-05-30 7:10 ` David Hildenbrand
2022-05-30 7:16 ` Muchun Song
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