diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2016-08-17 17:36:29 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-09-15 08:27:53 +0200 |
| commit | f964b3b368b59cc03e26d3f5b5226432b22d9a0d (patch) | |
| tree | 5c95231dc5b36955b585cdf7d3188a573f7516e0 /kernel | |
| parent | 2e133f2d2cf40736ebc028ffa11dd907dc0753eb (diff) | |
uprobes: Fix the memcg accounting
commit 6c4687cc17a788a6dd8de3e27dbeabb7cbd3e066 upstream.
__replace_page() wronlgy calls mem_cgroup_cancel_charge() in "success" path,
it should only do this if page_check_address() fails.
This means that every enable/disable leads to unbalanced mem_cgroup_uncharge()
from put_page(old_page), it is trivial to underflow the page_counter->count
and trigger OOM.
Reported-and-tested-by: Brenden Blanco <bblanco@plumgrid.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Fixes: 00501b531c47 ("mm: memcontrol: rewrite charge API")
Link: http://lkml.kernel.org/r/20160817153629.GB29724@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/events/uprobes.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 7dad84913abf..da0c09ff6112 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -171,8 +171,10 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr, mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); err = -EAGAIN; ptep = page_check_address(page, mm, addr, &ptl, 0); - if (!ptep) + if (!ptep) { + mem_cgroup_cancel_charge(kpage, memcg); goto unlock; + } get_page(kpage); page_add_new_anon_rmap(kpage, vma, addr); @@ -199,7 +201,6 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr, err = 0; unlock: - mem_cgroup_cancel_charge(kpage, memcg); mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); unlock_page(page); return err; |