diff mbox series

xfs: check the return value of krealloc() in xfs_uuid_mount

Message ID 20201125065036.154312-1-miaoqinglang@huawei.com (mailing list archive)
State New
Headers show
Series xfs: check the return value of krealloc() in xfs_uuid_mount | expand

Commit Message

Qinglang Miao Nov. 25, 2020, 6:50 a.m. UTC
krealloc() may fail to expand the memory space. Add sanity checks to it,
and WARN() if that really happened.

Fixes: 771915c4f688 ("xfs: remove kmem_realloc()")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
---
 fs/xfs/xfs_mount.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

Comments

Eric Sandeen Nov. 25, 2020, 3:55 p.m. UTC | #1
On 11/25/20 12:50 AM, Qinglang Miao wrote:
> krealloc() may fail to expand the memory space.

Even with __GFP_NOFAIL?

  * ``GFP_KERNEL | __GFP_NOFAIL`` - overrides the default allocator behavior
    and all allocation requests will loop endlessly until they succeed.
    This might be really dangerous especially for larger orders.

> Add sanity checks to it,
> and WARN() if that really happened.

As aside, there is no WARN added in this patch for a memory failure.

> Fixes: 771915c4f688 ("xfs: remove kmem_realloc()")
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
> ---
>  fs/xfs/xfs_mount.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
> index 150ee5cb8..c07f48c32 100644
> --- a/fs/xfs/xfs_mount.c
> +++ b/fs/xfs/xfs_mount.c
> @@ -80,9 +80,13 @@ xfs_uuid_mount(
>  	}
>  
>  	if (hole < 0) {
> -		xfs_uuid_table = krealloc(xfs_uuid_table,
> +		uuid_t *if_xfs_uuid_table;
> +		if_xfs_uuid_table = krealloc(xfs_uuid_table,
>  			(xfs_uuid_table_size + 1) * sizeof(*xfs_uuid_table),
>  			GFP_KERNEL | __GFP_NOFAIL);
> +		if (!if_xfs_uuid_table)
> +			goto out_duplicate;

And this would emit "Filesystem has duplicate UUID" which is not correct.

But anyway, the __GFP_NOFAIL in the call makes this all moot AFAICT.

-Eric

> +		xfs_uuid_table = if_xfs_uuid_table;
>  		hole = xfs_uuid_table_size++;
>  	}
>  	xfs_uuid_table[hole] = *uuid;
>
Qinglang Miao Nov. 26, 2020, 1:21 a.m. UTC | #2
在 2020/11/25 23:55, Eric Sandeen 写道:
> On 11/25/20 12:50 AM, Qinglang Miao wrote:
>> krealloc() may fail to expand the memory space.
> 
> Even with __GFP_NOFAIL?
> 
>    * ``GFP_KERNEL | __GFP_NOFAIL`` - overrides the default allocator behavior
>      and all allocation requests will loop endlessly until they succeed.
>      This might be really dangerous especially for larger orders.
> 
>> Add sanity checks to it,
>> and WARN() if that really happened.
> 
> As aside, there is no WARN added in this patch for a memory failure.
> 
>> Fixes: 771915c4f688 ("xfs: remove kmem_realloc()")
>> Reported-by: Hulk Robot <hulkci@huawei.com>
>> Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
>> ---
>>   fs/xfs/xfs_mount.c | 6 +++++-
>>   1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
>> index 150ee5cb8..c07f48c32 100644
>> --- a/fs/xfs/xfs_mount.c
>> +++ b/fs/xfs/xfs_mount.c
>> @@ -80,9 +80,13 @@ xfs_uuid_mount(
>>   	}
>>   
>>   	if (hole < 0) {
>> -		xfs_uuid_table = krealloc(xfs_uuid_table,
>> +		uuid_t *if_xfs_uuid_table;
>> +		if_xfs_uuid_table = krealloc(xfs_uuid_table,
>>   			(xfs_uuid_table_size + 1) * sizeof(*xfs_uuid_table),
>>   			GFP_KERNEL | __GFP_NOFAIL);
>> +		if (!if_xfs_uuid_table)
>> +			goto out_duplicate;
> 
> And this would emit "Filesystem has duplicate UUID" which is not correct.
> 
> But anyway, the __GFP_NOFAIL in the call makes this all moot AFAICT.
> 
> -Eric
Hi Eric,

Sorry for neglecting __GFP_NOFAIL symbol, and I would add a WARN in 
memory failure next time.

Thanks for your advice!
> 
>> +		xfs_uuid_table = if_xfs_uuid_table;
>>   		hole = xfs_uuid_table_size++;
>>   	}
>>   	xfs_uuid_table[hole] = *uuid;
>>
> .
>
Gao Xiang Nov. 26, 2020, 2:16 a.m. UTC | #3
Hi Qinglang,

On Thu, Nov 26, 2020 at 09:21:11AM +0800, Qinglang Miao wrote:
> 
> 
> 在 2020/11/25 23:55, Eric Sandeen 写道:
> > On 11/25/20 12:50 AM, Qinglang Miao wrote:
> > > krealloc() may fail to expand the memory space.
> > 
> > Even with __GFP_NOFAIL?
> > 
> >    * ``GFP_KERNEL | __GFP_NOFAIL`` - overrides the default allocator behavior
> >      and all allocation requests will loop endlessly until they succeed.
> >      This might be really dangerous especially for larger orders.
> > 
> > > Add sanity checks to it,
> > > and WARN() if that really happened.
> > 
> > As aside, there is no WARN added in this patch for a memory failure.
> > 
> > > Fixes: 771915c4f688 ("xfs: remove kmem_realloc()")
> > > Reported-by: Hulk Robot <hulkci@huawei.com>
> > > Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
> > > ---
> > >   fs/xfs/xfs_mount.c | 6 +++++-
> > >   1 file changed, 5 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
> > > index 150ee5cb8..c07f48c32 100644
> > > --- a/fs/xfs/xfs_mount.c
> > > +++ b/fs/xfs/xfs_mount.c
> > > @@ -80,9 +80,13 @@ xfs_uuid_mount(
> > >   	}
> > >   	if (hole < 0) {
> > > -		xfs_uuid_table = krealloc(xfs_uuid_table,
> > > +		uuid_t *if_xfs_uuid_table;
> > > +		if_xfs_uuid_table = krealloc(xfs_uuid_table,
> > >   			(xfs_uuid_table_size + 1) * sizeof(*xfs_uuid_table),
> > >   			GFP_KERNEL | __GFP_NOFAIL);
> > > +		if (!if_xfs_uuid_table)
> > > +			goto out_duplicate;
> > 
> > And this would emit "Filesystem has duplicate UUID" which is not correct.
> > 
> > But anyway, the __GFP_NOFAIL in the call makes this all moot AFAICT.
> > 
> > -Eric
> Hi Eric,
> 
> Sorry for neglecting __GFP_NOFAIL symbol, and I would add a WARN in memory
> failure next time.

Sorry about my limited knowledge, but why it needs a WARN here since
I think it will never fail if __GFP_NOFAIL is added (no ?).

I'm not sure if Hulk CI is completely broken or not on this, also if
such CI can now generate trivial patch (?) since the subject, commit
message and even the variable name is quite similiar to
https://lore.kernel.org/linux-xfs/20201124104531.561-2-thunder.leizhen@huawei.com
in a day.

And it'd be better to look into the code before sending patches...

Thanks,
Gao Xiang

> 
> Thanks for your advice!
>
Qinglang Miao Nov. 26, 2020, 3:05 a.m. UTC | #4
在 2020/11/26 10:16, Gao Xiang 写道:
> Hi Qinglang,
> 
> On Thu, Nov 26, 2020 at 09:21:11AM +0800, Qinglang Miao wrote:
>>
>>
>> 在 2020/11/25 23:55, Eric Sandeen 写道:
>>> On 11/25/20 12:50 AM, Qinglang Miao wrote:
>>>> krealloc() may fail to expand the memory space.
>>>
>>> Even with __GFP_NOFAIL?
>>>
>>>     * ``GFP_KERNEL | __GFP_NOFAIL`` - overrides the default allocator behavior
>>>       and all allocation requests will loop endlessly until they succeed.
>>>       This might be really dangerous especially for larger orders.
>>>
>>>> Add sanity checks to it,
>>>> and WARN() if that really happened.
>>>
>>> As aside, there is no WARN added in this patch for a memory failure.
>>>
>>>> Fixes: 771915c4f688 ("xfs: remove kmem_realloc()")
>>>> Reported-by: Hulk Robot <hulkci@huawei.com>
>>>> Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
>>>> ---
>>>>    fs/xfs/xfs_mount.c | 6 +++++-
>>>>    1 file changed, 5 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
>>>> index 150ee5cb8..c07f48c32 100644
>>>> --- a/fs/xfs/xfs_mount.c
>>>> +++ b/fs/xfs/xfs_mount.c
>>>> @@ -80,9 +80,13 @@ xfs_uuid_mount(
>>>>    	}
>>>>    	if (hole < 0) {
>>>> -		xfs_uuid_table = krealloc(xfs_uuid_table,
>>>> +		uuid_t *if_xfs_uuid_table;
>>>> +		if_xfs_uuid_table = krealloc(xfs_uuid_table,
>>>>    			(xfs_uuid_table_size + 1) * sizeof(*xfs_uuid_table),
>>>>    			GFP_KERNEL | __GFP_NOFAIL);
>>>> +		if (!if_xfs_uuid_table)
>>>> +			goto out_duplicate;
>>>
>>> And this would emit "Filesystem has duplicate UUID" which is not correct.
>>>
>>> But anyway, the __GFP_NOFAIL in the call makes this all moot AFAICT.
>>>
>>> -Eric
>> Hi Eric,
>>
>> Sorry for neglecting __GFP_NOFAIL symbol, and I would add a WARN in memory
>> failure next time.
> 
> Sorry about my limited knowledge, but why it needs a WARN here since
> I think it will never fail if __GFP_NOFAIL is added (no ?).
'next time' means next time when I send patches related to memory 
failure, not on this one. Sorry for making confusing to you.
> 
> I'm not sure if Hulk CI is completely broken or not on this, also if
> such CI can now generate trivial patch (?) since the subject, commit
> message and even the variable name is quite similiar to
> https://lore.kernel.org/linux-xfs/20201124104531.561-2-thunder.leizhen@huawei.com
> in a day.
> 
> And it'd be better to look into the code before sending patches...
Yeah..  I should pay more attension.
> 
> Thanks,
> Gao Xiang >
Thanks for your advice~
>>
>> Thanks for your advice!
>>
> 
> .
>
Gao Xiang Nov. 26, 2020, 3:13 a.m. UTC | #5
On Thu, Nov 26, 2020 at 11:05:03AM +0800, Qinglang Miao wrote:

...

> > 
> > I'm not sure if Hulk CI is completely broken or not on this, also if
> > such CI can now generate trivial patch (?) since the subject, commit
> > message and even the variable name is quite similiar to
> > https://lore.kernel.org/linux-xfs/20201124104531.561-2-thunder.leizhen@huawei.com
> > in a day.
> > 
> > And it'd be better to look into the code before sending patches...
> Yeah..  I should pay more attension.

Yeah, it'd be better to address/fix the Hulk CI false report
if possible, so it won't have such warning in the future.

Thanks,
Gao Xiang

> > 
> > Thanks,
> > Gao Xiang >
> Thanks for your advice~
> > > 
> > > Thanks for your advice!
> > > 
> > 
> > .
> > 
>
diff mbox series

Patch

diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 150ee5cb8..c07f48c32 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -80,9 +80,13 @@  xfs_uuid_mount(
 	}
 
 	if (hole < 0) {
-		xfs_uuid_table = krealloc(xfs_uuid_table,
+		uuid_t *if_xfs_uuid_table;
+		if_xfs_uuid_table = krealloc(xfs_uuid_table,
 			(xfs_uuid_table_size + 1) * sizeof(*xfs_uuid_table),
 			GFP_KERNEL | __GFP_NOFAIL);
+		if (!if_xfs_uuid_table)
+			goto out_duplicate;
+		xfs_uuid_table = if_xfs_uuid_table;
 		hole = xfs_uuid_table_size++;
 	}
 	xfs_uuid_table[hole] = *uuid;