2020-03-13 22:40:45

by Mina Almasry

Subject: [PATCH -next] hugetlb_cgroup: fix illegal access to memory

This appears to be a mistake in commit faced7e0806cf ("mm: hugetlb
controller for cgroups v2"). Essentially that commit does
a hugetlb_cgroup_from_counter assuming that page_counter_try_charge has
initialized counter, but if page_counter_try_charge has failed then it
seems it does not initialize counter, so
hugetlb_cgroup_from_counter(counter) ends up pointing to random memory,
causing kasan to complain.

Solution, simply use h_cg, instead of
hugetlb_cgroup_from_counter(counter), since that is a reference to the
hugetlb_cgroup anyway. After this change kasan ceases to complain.

Signed-off-by: Mina Almasry <[email protected]>
Reported-by: [email protected]
Fixes: commit faced7e0806cf ("mm: hugetlb controller for cgroups v2")
Cc: Andrew Morton <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Giuseppe Scrivano <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: [email protected]
Cc: [email protected]

---
mm/hugetlb_cgroup.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
index 7994eb8a2a0b4..aabf65d4d91ba 100644
--- a/mm/hugetlb_cgroup.c
+++ b/mm/hugetlb_cgroup.c
@@ -259,8 +259,7 @@ static int __hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
__hugetlb_cgroup_counter_from_cgroup(h_cg, idx, rsvd),
nr_pages, &counter)) {
ret = -ENOMEM;
- hugetlb_event(hugetlb_cgroup_from_counter(counter, idx), idx,
- HUGETLB_MAX);
+ hugetlb_event(h_cg, idx, HUGETLB_MAX);
css_put(&h_cg->css);
goto done;
}
--
2.25.1.481.gfbce0eb801-goog

2020-03-13 22:49:27

by Mina Almasry

Subject: Re: [PATCH -next] hugetlb_cgroup: fix illegal access to memory

On Fri, Mar 13, 2020 at 3:39 PM Mina Almasry <[email protected]> wrote:
>
> This appears to be a mistake in commit faced7e0806cf ("mm: hugetlb
> controller for cgroups v2"). Essentially that commit does
> a hugetlb_cgroup_from_counter assuming that page_counter_try_charge has
> initialized counter, but if page_counter_try_charge has failed then it
> seems it does not initialize counter, so
> hugetlb_cgroup_from_counter(counter) ends up pointing to random memory,
> causing kasan to complain.
>
> Solution, simply use h_cg, instead of
> hugetlb_cgroup_from_counter(counter), since that is a reference to the
> hugetlb_cgroup anyway. After this change kasan ceases to complain.
>
> Signed-off-by: Mina Almasry <[email protected]>
> Reported-by: [email protected]
> Fixes: commit faced7e0806cf ("mm: hugetlb controller for cgroups v2")
> Cc: Andrew Morton <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: Giuseppe Scrivano <[email protected]>
> Cc: Tejun Heo <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
>
> ---
> mm/hugetlb_cgroup.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
> index 7994eb8a2a0b4..aabf65d4d91ba 100644
> --- a/mm/hugetlb_cgroup.c
> +++ b/mm/hugetlb_cgroup.c
> @@ -259,8 +259,7 @@ static int __hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
> __hugetlb_cgroup_counter_from_cgroup(h_cg, idx, rsvd),
> nr_pages, &counter)) {
> ret = -ENOMEM;
> - hugetlb_event(hugetlb_cgroup_from_counter(counter, idx), idx,
> - HUGETLB_MAX);
> + hugetlb_event(h_cg, idx, HUGETLB_MAX);
> css_put(&h_cg->css);
> goto done;
> }
> --
> 2.25.1.481.gfbce0eb801-goog

The patch this fixes is in linus's tree, but isn't in 5.5 stable yet.

2020-03-15 02:22:23

by Giuseppe Scrivano

Subject: Re: [PATCH -next] hugetlb_cgroup: fix illegal access to memory

Mina Almasry <[email protected]> writes:

> On Fri, Mar 13, 2020 at 3:39 PM Mina Almasry <[email protected]> wrote:
>>
>> This appears to be a mistake in commit faced7e0806cf ("mm: hugetlb
>> controller for cgroups v2"). Essentially that commit does
>> a hugetlb_cgroup_from_counter assuming that page_counter_try_charge has
>> initialized counter, but if page_counter_try_charge has failed then it
>> seems it does not initialize counter, so
>> hugetlb_cgroup_from_counter(counter) ends up pointing to random memory,
>> causing kasan to complain.
>>
>> Solution, simply use h_cg, instead of
>> hugetlb_cgroup_from_counter(counter), since that is a reference to the
>> hugetlb_cgroup anyway. After this change kasan ceases to complain.
>>
>> Signed-off-by: Mina Almasry <[email protected]>
>> Reported-by: [email protected]
>> Fixes: commit faced7e0806cf ("mm: hugetlb controller for cgroups v2")
>> Cc: Andrew Morton <[email protected]>
>> Cc: [email protected]
>> Cc: [email protected]
>> Cc: Giuseppe Scrivano <[email protected]>
>> Cc: Tejun Heo <[email protected]>
>> Cc: [email protected]
>> Cc: [email protected]
>>
>> ---
>> mm/hugetlb_cgroup.c | 3 +--
>> 1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
>> index 7994eb8a2a0b4..aabf65d4d91ba 100644
>> --- a/mm/hugetlb_cgroup.c
>> +++ b/mm/hugetlb_cgroup.c
>> @@ -259,8 +259,7 @@ static int __hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
>> __hugetlb_cgroup_counter_from_cgroup(h_cg, idx, rsvd),
>> nr_pages, &counter)) {
>> ret = -ENOMEM;
>> - hugetlb_event(hugetlb_cgroup_from_counter(counter, idx), idx,
>> - HUGETLB_MAX);
>> + hugetlb_event(h_cg, idx, HUGETLB_MAX);
>> css_put(&h_cg->css);
>> goto done;
>> }
>> --
>> 2.25.1.481.gfbce0eb801-goog

Acked-by: Giuseppe Scrivano <[email protected]>

Thanks,
Giuseppe

2020-03-20 19:33:29

by Mina Almasry

Subject: Re: [PATCH -next] hugetlb_cgroup: fix illegal access to memory

Tejun/Mike you want to also give this a quick look?

On Sat, Mar 14, 2020 at 11:21 AM Giuseppe Scrivano <[email protected]> wrote:
>
> Mina Almasry <[email protected]> writes:
>
> > On Fri, Mar 13, 2020 at 3:39 PM Mina Almasry <[email protected]> wrote:
> >>
> >> This appears to be a mistake in commit faced7e0806cf ("mm: hugetlb
> >> controller for cgroups v2"). Essentially that commit does
> >> a hugetlb_cgroup_from_counter assuming that page_counter_try_charge has
> >> initialized counter, but if page_counter_try_charge has failed then it
> >> seems it does not initialize counter, so
> >> hugetlb_cgroup_from_counter(counter) ends up pointing to random memory,
> >> causing kasan to complain.
> >>
> >> Solution, simply use h_cg, instead of
> >> hugetlb_cgroup_from_counter(counter), since that is a reference to the
> >> hugetlb_cgroup anyway. After this change kasan ceases to complain.
> >>
> >> Signed-off-by: Mina Almasry <[email protected]>
> >> Reported-by: [email protected]
> >> Fixes: commit faced7e0806cf ("mm: hugetlb controller for cgroups v2")
> >> Cc: Andrew Morton <[email protected]>
> >> Cc: [email protected]
> >> Cc: [email protected]
> >> Cc: Giuseppe Scrivano <[email protected]>
> >> Cc: Tejun Heo <[email protected]>
> >> Cc: [email protected]
> >> Cc: [email protected]
> >>
> >> ---
> >> mm/hugetlb_cgroup.c | 3 +--
> >> 1 file changed, 1 insertion(+), 2 deletions(-)
> >>
> >> diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
> >> index 7994eb8a2a0b4..aabf65d4d91ba 100644
> >> --- a/mm/hugetlb_cgroup.c
> >> +++ b/mm/hugetlb_cgroup.c
> >> @@ -259,8 +259,7 @@ static int __hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
> >> __hugetlb_cgroup_counter_from_cgroup(h_cg, idx, rsvd),
> >> nr_pages, &counter)) {
> >> ret = -ENOMEM;
> >> - hugetlb_event(hugetlb_cgroup_from_counter(counter, idx), idx,
> >> - HUGETLB_MAX);
> >> + hugetlb_event(h_cg, idx, HUGETLB_MAX);
> >> css_put(&h_cg->css);
> >> goto done;
> >> }
> >> --
> >> 2.25.1.481.gfbce0eb801-goog
>
> Acked-by: Giuseppe Scrivano <[email protected]>
>
> Thanks,
> Giuseppe
>

2020-03-24 18:25:34

by Tejun Heo

Subject: Re: [PATCH -next] hugetlb_cgroup: fix illegal access to memory

On Fri, Mar 13, 2020 at 03:39:20PM -0700, Mina Almasry wrote:
> This appears to be a mistake in commit faced7e0806cf ("mm: hugetlb
> controller for cgroups v2"). Essentially that commit does
> a hugetlb_cgroup_from_counter assuming that page_counter_try_charge has
> initialized counter, but if page_counter_try_charge has failed then it
> seems it does not initialize counter, so
> hugetlb_cgroup_from_counter(counter) ends up pointing to random memory,
> causing kasan to complain.
>
> Solution, simply use h_cg, instead of
> hugetlb_cgroup_from_counter(counter), since that is a reference to the
> hugetlb_cgroup anyway. After this change kasan ceases to complain.
>
> Signed-off-by: Mina Almasry <[email protected]>
> Reported-by: [email protected]
> Fixes: commit faced7e0806cf ("mm: hugetlb controller for cgroups v2")
> Cc: Andrew Morton <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: Giuseppe Scrivano <[email protected]>
> Cc: Tejun Heo <[email protected]>
> Cc: [email protected]
> Cc: [email protected]

Acked-by: Tejun Heo <[email protected]>

Thanks.

--
tejun