Messages in this thread Patch in this message | | | From | Pavel Tikhomirov <> | Subject | [PATCH] mm/memcontrol: stop resize loop if limit was changed again | Date | Wed, 20 Mar 2024 18:03:30 +0800 |
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In memory_max_write() we first set memcg->memory.max and only then try to enforce it in loop. What if while we are in loop someone else have changed memcg->memory.max but we are still trying to enforce the old value? I believe this can lead to nasty consequence like getting an oom on perfectly fine cgroup within it's limits or excess reclaim.
We also have exactly the same thing in memory_high_write().
So let's stop enforcing old limits if we already have a new ones.
Signed-off-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com> --- mm/memcontrol.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 61932c9215e7..81b303728491 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -6769,6 +6769,9 @@ static ssize_t memory_high_write(struct kernfs_open_file *of, unsigned long nr_pages = page_counter_read(&memcg->memory); unsigned long reclaimed; + if (memcg->memory.high != high) + break; + if (nr_pages <= high) break; @@ -6817,6 +6820,9 @@ static ssize_t memory_max_write(struct kernfs_open_file *of, for (;;) { unsigned long nr_pages = page_counter_read(&memcg->memory); + if (memcg->memory.max != max) + break; + if (nr_pages <= max) break; -- 2.43.0
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