user_shm_lock forgets to set allowed to 0 when get_ucounts fails. So
the later user_shm_unlock might do the extra dec_rlimit_ucounts. Fix
this by resetting allowed to 0.
Fixes: d7c9e99aee48 ("Reimplement RLIMIT_MEMLOCK on top of ucounts")
Signed-off-by: Miaohe Lin <[email protected]>
Acked-by: Hugh Dickins <[email protected]>
---
v1->v2:
correct Fixes tag and collect Acked-by tag
Thanks Hugh for review!
---
mm/mlock.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/mm/mlock.c b/mm/mlock.c
index 29372c0eebe5..efd2dd2943de 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -733,6 +733,7 @@ int user_shm_lock(size_t size, struct ucounts *ucounts)
}
if (!get_ucounts(ucounts)) {
dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
+ allowed = 0;
goto out;
}
allowed = 1;
--
2.23.0
Miaohe Lin <[email protected]> writes:
> user_shm_lock forgets to set allowed to 0 when get_ucounts fails. So
> the later user_shm_unlock might do the extra dec_rlimit_ucounts. Fix
> this by resetting allowed to 0.
This fix looks correct. But the ability for people to follow and read
the code seems questionable. I saw in v1 of this patch Hugh originally
misread the logic.
Could we instead change the code to leave lock_limit at ULONG_MAX aka
RLIM_INFINITY, leave initialized to 0, and not even need a special case
of RLIM_INFINITY as nothing can be greater that ULONG_MAX?
Something like this?
diff --git a/mm/mlock.c b/mm/mlock.c
index 8f584eddd305..e7eabf5193ab 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -827,13 +827,12 @@ int user_shm_lock(size_t size, struct ucounts *ucounts)
locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
lock_limit = rlimit(RLIMIT_MEMLOCK);
- if (lock_limit == RLIM_INFINITY)
- allowed = 1;
- lock_limit >>= PAGE_SHIFT;
+ if (lock_limit != RLIM_INFINITY)
+ lock_limit >>= PAGE_SHIFT;
spin_lock(&shmlock_user_lock);
memlock = inc_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
- if (!allowed && (memlock == LONG_MAX || memlock > lock_limit) && !capable(CAP_IPC_LOCK)) {
+ if ((memlock == LONG_MAX || memlock > lock_limit) && !capable(CAP_IPC_LOCK)) {
dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
goto out;
}
>
> Fixes: d7c9e99aee48 ("Reimplement RLIMIT_MEMLOCK on top of ucounts")
> Signed-off-by: Miaohe Lin <[email protected]>
> Acked-by: Hugh Dickins <[email protected]>
> ---
> v1->v2:
> correct Fixes tag and collect Acked-by tag
> Thanks Hugh for review!
> ---
> mm/mlock.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/mm/mlock.c b/mm/mlock.c
> index 29372c0eebe5..efd2dd2943de 100644
> --- a/mm/mlock.c
> +++ b/mm/mlock.c
> @@ -733,6 +733,7 @@ int user_shm_lock(size_t size, struct ucounts *ucounts)
> }
> if (!get_ucounts(ucounts)) {
> dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
> + allowed = 0;
> goto out;
> }
> allowed = 1;
Eric
Miaohe Lin <[email protected]> writes:
> On 2022/3/14 23:21, Eric W. Biederman wrote:
>> Miaohe Lin <[email protected]> writes:
>>
>>> user_shm_lock forgets to set allowed to 0 when get_ucounts fails. So
>>> the later user_shm_unlock might do the extra dec_rlimit_ucounts. Fix
>>> this by resetting allowed to 0.
>>
>> This fix looks correct. But the ability for people to follow and read
>> the code seems questionable. I saw in v1 of this patch Hugh originally
>> misread the logic.
>>
>> Could we instead change the code to leave lock_limit at ULONG_MAX aka
>> RLIM_INFINITY, leave initialized to 0, and not even need a special case
>> of RLIM_INFINITY as nothing can be greater that ULONG_MAX?
>>
>
> Many thanks for your advice. This looks good but it seems this results in different
> behavior: When (memlock == LONG_MAX) && !capable(CAP_IPC_LOCK), we would fail now
> while it will always success without this change. We should avoid this difference.
> Or am I miss something? Maybe the origin patch is more suitable and
> simple?
Interesting. I think that is an unintended and necessary bug fix.
When memlock == LONG_MAX that means inc_rlimit_ucounts failed.
It either failed because at another level the limit was exceeded or
because the counter wrapped. In either case it is not appropriate to
succeed if inc_rlimit_ucounts detects a failure.
Which is a long way of saying I think we really want the simplification
because it found and fixed another bug as well.
Without the simplification I don't think I will be confident the code is
correct.
Eric
> Thanks.
>
>> Something like this?
>>
>> diff --git a/mm/mlock.c b/mm/mlock.c
>> index 8f584eddd305..e7eabf5193ab 100644
>> --- a/mm/mlock.c
>> +++ b/mm/mlock.c
>> @@ -827,13 +827,12 @@ int user_shm_lock(size_t size, struct ucounts *ucounts)
>>
>> locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
>> lock_limit = rlimit(RLIMIT_MEMLOCK);
>> - if (lock_limit == RLIM_INFINITY)
>> - allowed = 1;
>> - lock_limit >>= PAGE_SHIFT;
>> + if (lock_limit != RLIM_INFINITY)
>> + lock_limit >>= PAGE_SHIFT;
>> spin_lock(&shmlock_user_lock);
>> memlock = inc_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
>>
>> - if (!allowed && (memlock == LONG_MAX || memlock > lock_limit) && !capable(CAP_IPC_LOCK)) {
>> + if ((memlock == LONG_MAX || memlock > lock_limit) && !capable(CAP_IPC_LOCK)) {
>> dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
>> goto out;
>> }
>>
>>>
>>> Fixes: d7c9e99aee48 ("Reimplement RLIMIT_MEMLOCK on top of ucounts")
>>> Signed-off-by: Miaohe Lin <[email protected]>
>>> Acked-by: Hugh Dickins <[email protected]>
>>> ---
>>> v1->v2:
>>> correct Fixes tag and collect Acked-by tag
>>> Thanks Hugh for review!
>>> ---
>>> mm/mlock.c | 1 +
>>> 1 file changed, 1 insertion(+)
>>>
>>> diff --git a/mm/mlock.c b/mm/mlock.c
>>> index 29372c0eebe5..efd2dd2943de 100644
>>> --- a/mm/mlock.c
>>> +++ b/mm/mlock.c
>>> @@ -733,6 +733,7 @@ int user_shm_lock(size_t size, struct ucounts *ucounts)
>>> }
>>> if (!get_ucounts(ucounts)) {
>>> dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
>>> + allowed = 0;
>>> goto out;
>>> }
>>> allowed = 1;
>>
>> Eric
>> .
>>
On 2022/3/16 22:11, Eric W. Biederman wrote:
> Miaohe Lin <[email protected]> writes:
>
>> On 2022/3/16 2:32, Eric W. Biederman wrote:
>>> Miaohe Lin <[email protected]> writes:
>>>
>>>> On 2022/3/14 23:21, Eric W. Biederman wrote:
>>>>> Miaohe Lin <[email protected]> writes:
>>>>>
>>>>>> user_shm_lock forgets to set allowed to 0 when get_ucounts fails. So
>>>>>> the later user_shm_unlock might do the extra dec_rlimit_ucounts. Fix
>>>>>> this by resetting allowed to 0.
>>>>>
>>>>> This fix looks correct. But the ability for people to follow and read
>>>>> the code seems questionable. I saw in v1 of this patch Hugh originally
>>>>> misread the logic.
>>>>>
>>>>> Could we instead change the code to leave lock_limit at ULONG_MAX aka
>>>>> RLIM_INFINITY, leave initialized to 0, and not even need a special case
>>>>> of RLIM_INFINITY as nothing can be greater that ULONG_MAX?
>>>>>
>>>>
>>>> Many thanks for your advice. This looks good but it seems this results in different
>>>> behavior: When (memlock == LONG_MAX) && !capable(CAP_IPC_LOCK), we would fail now
>>>> while it will always success without this change. We should avoid this difference.
>>>> Or am I miss something? Maybe the origin patch is more suitable and
>>>> simple?
>>>
>>> Interesting. I think that is an unintended and necessary bug fix.
>>>
>>> When memlock == LONG_MAX that means inc_rlimit_ucounts failed.
>>>
>>> It either failed because at another level the limit was exceeded or
>>> because the counter wrapped. In either case it is not appropriate to
>>> succeed if inc_rlimit_ucounts detects a failure.
>>>
>>> Which is a long way of saying I think we really want the simplification
>>> because it found and fixed another bug as well.
>>>
>>> Without the simplification I don't think I will be confident the code is
>>> correct.
>>
>> Agree with you. This is a potential bug and you just catch it with the
>> code simplification. :)
>>
>> Am I supposed to do this altogether or will you do this simplification part?
>> Many thanks.
>
> If you can that would be great, and you can have the credit.
>
> Otherwise I will make my proposed changes into a proper patch. At this
> point we just need to dot the i's and cross the t's and get this fix in.
I will try to do this. Many thanks!
>
> Eric
>
>>>>> Something like this?
>>>>>
>>>>> diff --git a/mm/mlock.c b/mm/mlock.c
>>>>> index 8f584eddd305..e7eabf5193ab 100644
>>>>> --- a/mm/mlock.c
>>>>> +++ b/mm/mlock.c
>>>>> @@ -827,13 +827,12 @@ int user_shm_lock(size_t size, struct ucounts *ucounts)
>>>>>
>>>>> locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
>>>>> lock_limit = rlimit(RLIMIT_MEMLOCK);
>>>>> - if (lock_limit == RLIM_INFINITY)
>>>>> - allowed = 1;
>>>>> - lock_limit >>= PAGE_SHIFT;
>>>>> + if (lock_limit != RLIM_INFINITY)
>>>>> + lock_limit >>= PAGE_SHIFT;
>>>>> spin_lock(&shmlock_user_lock);
>>>>> memlock = inc_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
>>>>>
>>>>> - if (!allowed && (memlock == LONG_MAX || memlock > lock_limit) && !capable(CAP_IPC_LOCK)) {
>>>>> + if ((memlock == LONG_MAX || memlock > lock_limit) && !capable(CAP_IPC_LOCK)) {
>>>>> dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
>>>>> goto out;
>>>>> }
>>>>>
>>>>>>
>>>>>> Fixes: d7c9e99aee48 ("Reimplement RLIMIT_MEMLOCK on top of ucounts")
>>>>>> Signed-off-by: Miaohe Lin <[email protected]>
>>>>>> Acked-by: Hugh Dickins <[email protected]>
>>>>>> ---
>>>>>> v1->v2:
>>>>>> correct Fixes tag and collect Acked-by tag
>>>>>> Thanks Hugh for review!
>>>>>> ---
>>>>>> mm/mlock.c | 1 +
>>>>>> 1 file changed, 1 insertion(+)
>>>>>>
>>>>>> diff --git a/mm/mlock.c b/mm/mlock.c
>>>>>> index 29372c0eebe5..efd2dd2943de 100644
>>>>>> --- a/mm/mlock.c
>>>>>> +++ b/mm/mlock.c
>>>>>> @@ -733,6 +733,7 @@ int user_shm_lock(size_t size, struct ucounts *ucounts)
>>>>>> }
>>>>>> if (!get_ucounts(ucounts)) {
>>>>>> dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
>>>>>> + allowed = 0;
>>>>>> goto out;
>>>>>> }
>>>>>> allowed = 1;
>>>>>
>>>>> Eric
>>>>> .
>>>>>
>>> .
>>>
> .
>
On 2022/3/14 23:21, Eric W. Biederman wrote:
> Miaohe Lin <[email protected]> writes:
>
>> user_shm_lock forgets to set allowed to 0 when get_ucounts fails. So
>> the later user_shm_unlock might do the extra dec_rlimit_ucounts. Fix
>> this by resetting allowed to 0.
>
> This fix looks correct. But the ability for people to follow and read
> the code seems questionable. I saw in v1 of this patch Hugh originally
> misread the logic.
>
> Could we instead change the code to leave lock_limit at ULONG_MAX aka
> RLIM_INFINITY, leave initialized to 0, and not even need a special case
> of RLIM_INFINITY as nothing can be greater that ULONG_MAX?
>
Many thanks for your advice. This looks good but it seems this results in different
behavior: When (memlock == LONG_MAX) && !capable(CAP_IPC_LOCK), we would fail now
while it will always success without this change. We should avoid this difference.
Or am I miss something? Maybe the origin patch is more suitable and simple?
Thanks.
> Something like this?
>
> diff --git a/mm/mlock.c b/mm/mlock.c
> index 8f584eddd305..e7eabf5193ab 100644
> --- a/mm/mlock.c
> +++ b/mm/mlock.c
> @@ -827,13 +827,12 @@ int user_shm_lock(size_t size, struct ucounts *ucounts)
>
> locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
> lock_limit = rlimit(RLIMIT_MEMLOCK);
> - if (lock_limit == RLIM_INFINITY)
> - allowed = 1;
> - lock_limit >>= PAGE_SHIFT;
> + if (lock_limit != RLIM_INFINITY)
> + lock_limit >>= PAGE_SHIFT;
> spin_lock(&shmlock_user_lock);
> memlock = inc_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
>
> - if (!allowed && (memlock == LONG_MAX || memlock > lock_limit) && !capable(CAP_IPC_LOCK)) {
> + if ((memlock == LONG_MAX || memlock > lock_limit) && !capable(CAP_IPC_LOCK)) {
> dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
> goto out;
> }
>
>>
>> Fixes: d7c9e99aee48 ("Reimplement RLIMIT_MEMLOCK on top of ucounts")
>> Signed-off-by: Miaohe Lin <[email protected]>
>> Acked-by: Hugh Dickins <[email protected]>
>> ---
>> v1->v2:
>> correct Fixes tag and collect Acked-by tag
>> Thanks Hugh for review!
>> ---
>> mm/mlock.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/mm/mlock.c b/mm/mlock.c
>> index 29372c0eebe5..efd2dd2943de 100644
>> --- a/mm/mlock.c
>> +++ b/mm/mlock.c
>> @@ -733,6 +733,7 @@ int user_shm_lock(size_t size, struct ucounts *ucounts)
>> }
>> if (!get_ucounts(ucounts)) {
>> dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
>> + allowed = 0;
>> goto out;
>> }
>> allowed = 1;
>
> Eric
> .
>
Miaohe Lin <[email protected]> writes:
> On 2022/3/16 2:32, Eric W. Biederman wrote:
>> Miaohe Lin <[email protected]> writes:
>>
>>> On 2022/3/14 23:21, Eric W. Biederman wrote:
>>>> Miaohe Lin <[email protected]> writes:
>>>>
>>>>> user_shm_lock forgets to set allowed to 0 when get_ucounts fails. So
>>>>> the later user_shm_unlock might do the extra dec_rlimit_ucounts. Fix
>>>>> this by resetting allowed to 0.
>>>>
>>>> This fix looks correct. But the ability for people to follow and read
>>>> the code seems questionable. I saw in v1 of this patch Hugh originally
>>>> misread the logic.
>>>>
>>>> Could we instead change the code to leave lock_limit at ULONG_MAX aka
>>>> RLIM_INFINITY, leave initialized to 0, and not even need a special case
>>>> of RLIM_INFINITY as nothing can be greater that ULONG_MAX?
>>>>
>>>
>>> Many thanks for your advice. This looks good but it seems this results in different
>>> behavior: When (memlock == LONG_MAX) && !capable(CAP_IPC_LOCK), we would fail now
>>> while it will always success without this change. We should avoid this difference.
>>> Or am I miss something? Maybe the origin patch is more suitable and
>>> simple?
>>
>> Interesting. I think that is an unintended and necessary bug fix.
>>
>> When memlock == LONG_MAX that means inc_rlimit_ucounts failed.
>>
>> It either failed because at another level the limit was exceeded or
>> because the counter wrapped. In either case it is not appropriate to
>> succeed if inc_rlimit_ucounts detects a failure.
>>
>> Which is a long way of saying I think we really want the simplification
>> because it found and fixed another bug as well.
>>
>> Without the simplification I don't think I will be confident the code is
>> correct.
>
> Agree with you. This is a potential bug and you just catch it with the
> code simplification. :)
>
> Am I supposed to do this altogether or will you do this simplification part?
> Many thanks.
If you can that would be great, and you can have the credit.
Otherwise I will make my proposed changes into a proper patch. At this
point we just need to dot the i's and cross the t's and get this fix in.
Eric
>>>> Something like this?
>>>>
>>>> diff --git a/mm/mlock.c b/mm/mlock.c
>>>> index 8f584eddd305..e7eabf5193ab 100644
>>>> --- a/mm/mlock.c
>>>> +++ b/mm/mlock.c
>>>> @@ -827,13 +827,12 @@ int user_shm_lock(size_t size, struct ucounts *ucounts)
>>>>
>>>> locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
>>>> lock_limit = rlimit(RLIMIT_MEMLOCK);
>>>> - if (lock_limit == RLIM_INFINITY)
>>>> - allowed = 1;
>>>> - lock_limit >>= PAGE_SHIFT;
>>>> + if (lock_limit != RLIM_INFINITY)
>>>> + lock_limit >>= PAGE_SHIFT;
>>>> spin_lock(&shmlock_user_lock);
>>>> memlock = inc_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
>>>>
>>>> - if (!allowed && (memlock == LONG_MAX || memlock > lock_limit) && !capable(CAP_IPC_LOCK)) {
>>>> + if ((memlock == LONG_MAX || memlock > lock_limit) && !capable(CAP_IPC_LOCK)) {
>>>> dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
>>>> goto out;
>>>> }
>>>>
>>>>>
>>>>> Fixes: d7c9e99aee48 ("Reimplement RLIMIT_MEMLOCK on top of ucounts")
>>>>> Signed-off-by: Miaohe Lin <[email protected]>
>>>>> Acked-by: Hugh Dickins <[email protected]>
>>>>> ---
>>>>> v1->v2:
>>>>> correct Fixes tag and collect Acked-by tag
>>>>> Thanks Hugh for review!
>>>>> ---
>>>>> mm/mlock.c | 1 +
>>>>> 1 file changed, 1 insertion(+)
>>>>>
>>>>> diff --git a/mm/mlock.c b/mm/mlock.c
>>>>> index 29372c0eebe5..efd2dd2943de 100644
>>>>> --- a/mm/mlock.c
>>>>> +++ b/mm/mlock.c
>>>>> @@ -733,6 +733,7 @@ int user_shm_lock(size_t size, struct ucounts *ucounts)
>>>>> }
>>>>> if (!get_ucounts(ucounts)) {
>>>>> dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
>>>>> + allowed = 0;
>>>>> goto out;
>>>>> }
>>>>> allowed = 1;
>>>>
>>>> Eric
>>>> .
>>>>
>> .
>>
On 2022/3/16 2:32, Eric W. Biederman wrote:
> Miaohe Lin <[email protected]> writes:
>
>> On 2022/3/14 23:21, Eric W. Biederman wrote:
>>> Miaohe Lin <[email protected]> writes:
>>>
>>>> user_shm_lock forgets to set allowed to 0 when get_ucounts fails. So
>>>> the later user_shm_unlock might do the extra dec_rlimit_ucounts. Fix
>>>> this by resetting allowed to 0.
>>>
>>> This fix looks correct. But the ability for people to follow and read
>>> the code seems questionable. I saw in v1 of this patch Hugh originally
>>> misread the logic.
>>>
>>> Could we instead change the code to leave lock_limit at ULONG_MAX aka
>>> RLIM_INFINITY, leave initialized to 0, and not even need a special case
>>> of RLIM_INFINITY as nothing can be greater that ULONG_MAX?
>>>
>>
>> Many thanks for your advice. This looks good but it seems this results in different
>> behavior: When (memlock == LONG_MAX) && !capable(CAP_IPC_LOCK), we would fail now
>> while it will always success without this change. We should avoid this difference.
>> Or am I miss something? Maybe the origin patch is more suitable and
>> simple?
>
> Interesting. I think that is an unintended and necessary bug fix.
>
> When memlock == LONG_MAX that means inc_rlimit_ucounts failed.
>
> It either failed because at another level the limit was exceeded or
> because the counter wrapped. In either case it is not appropriate to
> succeed if inc_rlimit_ucounts detects a failure.
>
> Which is a long way of saying I think we really want the simplification
> because it found and fixed another bug as well.
>
> Without the simplification I don't think I will be confident the code is
> correct.
Agree with you. This is a potential bug and you just catch it with the
code simplification. :)
Am I supposed to do this altogether or will you do this simplification part?
Many thanks.
>
> Eric
>
>
>> Thanks.
>>
>>> Something like this?
>>>
>>> diff --git a/mm/mlock.c b/mm/mlock.c
>>> index 8f584eddd305..e7eabf5193ab 100644
>>> --- a/mm/mlock.c
>>> +++ b/mm/mlock.c
>>> @@ -827,13 +827,12 @@ int user_shm_lock(size_t size, struct ucounts *ucounts)
>>>
>>> locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
>>> lock_limit = rlimit(RLIMIT_MEMLOCK);
>>> - if (lock_limit == RLIM_INFINITY)
>>> - allowed = 1;
>>> - lock_limit >>= PAGE_SHIFT;
>>> + if (lock_limit != RLIM_INFINITY)
>>> + lock_limit >>= PAGE_SHIFT;
>>> spin_lock(&shmlock_user_lock);
>>> memlock = inc_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
>>>
>>> - if (!allowed && (memlock == LONG_MAX || memlock > lock_limit) && !capable(CAP_IPC_LOCK)) {
>>> + if ((memlock == LONG_MAX || memlock > lock_limit) && !capable(CAP_IPC_LOCK)) {
>>> dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
>>> goto out;
>>> }
>>>
>>>>
>>>> Fixes: d7c9e99aee48 ("Reimplement RLIMIT_MEMLOCK on top of ucounts")
>>>> Signed-off-by: Miaohe Lin <[email protected]>
>>>> Acked-by: Hugh Dickins <[email protected]>
>>>> ---
>>>> v1->v2:
>>>> correct Fixes tag and collect Acked-by tag
>>>> Thanks Hugh for review!
>>>> ---
>>>> mm/mlock.c | 1 +
>>>> 1 file changed, 1 insertion(+)
>>>>
>>>> diff --git a/mm/mlock.c b/mm/mlock.c
>>>> index 29372c0eebe5..efd2dd2943de 100644
>>>> --- a/mm/mlock.c
>>>> +++ b/mm/mlock.c
>>>> @@ -733,6 +733,7 @@ int user_shm_lock(size_t size, struct ucounts *ucounts)
>>>> }
>>>> if (!get_ucounts(ucounts)) {
>>>> dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
>>>> + allowed = 0;
>>>> goto out;
>>>> }
>>>> allowed = 1;
>>>
>>> Eric
>>> .
>>>
> .
>