The patch titled Subject: mm, memcg: fix corruption on 64-bit divisor in memory.high throttling has been added to the -mm tree. Its filename is mm-memcg-fix-corruption-on-64-bit-divisor-in-memoryhigh-throttling.patch

This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-memcg-fix-corruption-on-64-bit-d... and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-memcg-fix-corruption-on-64-bit-d...

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------------------------------------------------------ From: Chris Down chris@chrisdown.name Subject: mm, memcg: fix corruption on 64-bit divisor in memory.high throttling

0e4b01df8659 had a bunch of fixups to use the right division method. However, it seems that after all that it still wasn't right -- div_u64 takes a 32-bit divisor.

The headroom is still large (2^32 pages), so on mundane systems you won't hit this, but this should definitely be fixed.

Link: http://lkml.kernel.org/r/80780887060514967d414b3cd91f9a316a16ab98.1584036142... Fixes: 0e4b01df8659 ("mm, memcg: throttle allocators when failing reclaim over memory.high") Signed-off-by: Chris Down chris@chrisdown.name Reported-by: Johannes Weiner hannes@cmpxchg.org Cc: Tejun Heo tj@kernel.org Cc: Roman Gushchin guro@fb.com Cc: Michal Hocko mhocko@kernel.org Cc: Nathan Chancellor natechancellor@gmail.com Cc: stable@vger.kernel.org [5.4.x+] Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

mm/memcontrol.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/memcontrol.c~mm-memcg-fix-corruption-on-64-bit-divisor-in-memoryhigh-throttling +++ a/mm/memcontrol.c @@ -2350,7 +2350,7 @@ void mem_cgroup_handle_over_high(void) */ clamped_high = max(high, 1UL);

- overage = div_u64((u64)(usage - high) << MEMCG_DELAY_PRECISION_SHIFT, + overage = div64_u64((u64)(usage - high) << MEMCG_DELAY_PRECISION_SHIFT, clamped_high);

penalty_jiffies = ((u64)overage * overage * HZ) _

Patches currently in -mm which might be from chris@chrisdown.name are

mm-memcg-fix-corruption-on-64-bit-divisor-in-memoryhigh-throttling.patch mm-memcg-throttle-allocators-based-on-ancestral-memoryhigh.patch