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authorMina Almasry <almasrymina@google.com>2020-03-28 19:17:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-03-29 09:47:05 -0700
commit726b7bbeafd4e0219c37b74673d368b21ff3d039 (patch)
tree9801d33f07d79e84333f425495415a61e4838a01
parent53cdc1cb29e87ce5a61de5bb393eb08925d14ede (diff)
downloadlinux-726b7bbeafd4e0219c37b74673d368b21ff3d039.tar.bz2
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>
-rw-r--r--mm/hugetlb_cgroup.c3
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: