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| author | Mina Almasry <almasrymina@google.com> | 2020-03-28 19:17:22 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-03-29 09:47:05 -0700 |
| commit | 726b7bbeafd4e0219c37b74673d368b21ff3d039 (patch) | |
| tree | 9801d33f07d79e84333f425495415a61e4838a01 /mm/hugetlb_cgroup.c | |
| parent | 53cdc1cb29e87ce5a61de5bb393eb08925d14ede (diff) | |
| download | lwn-726b7bbeafd4e0219c37b74673d368b21ff3d039.tar.gz lwn-726b7bbeafd4e0219c37b74673d368b21ff3d039.zip | |
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 that has failed then it seems will not initialize counter, so
hugetlb_cgroup_from_counter(counter) ends up pointing to random memory,
causing kasan to complain.
The solution is to 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.
Fixes: faced7e0806cf ("mm: hugetlb controller for cgroups v2")
Reported-by: syzbot+cac0c4e204952cf449b1@syzkaller.appspotmail.com
Signed-off-by: Mina Almasry <almasrymina@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Giuseppe Scrivano <gscrivan@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Link: http://lkml.kernel.org/r/20200313223920.124230-1-almasrymina@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/hugetlb_cgroup.c')
| -rw-r--r-- | mm/hugetlb_cgroup.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c index e434b05416c6..5280bcf459af 100644 --- a/mm/hugetlb_cgroup.c +++ b/mm/hugetlb_cgroup.c @@ -240,8 +240,7 @@ again: if (!page_counter_try_charge(&h_cg->hugepage[idx], 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); done: |