All of lore.kernel.org
 help / color / mirror / Atom feed
From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, chris@chrisdown.name, guro@fb.com,
	hannes@cmpxchg.org, linux-mm@kvack.org, mhocko@kernel.org,
	mm-commits@vger.kernel.org, natechancellor@gmail.com,
	stable@vger.kernel.org, tj@kernel.org,
	torvalds@linux-foundation.org
Subject: [patch 04/10] mm, memcg: fix corruption on 64-bit divisor in memory.high throttling
Date: Sat, 21 Mar 2020 18:22:20 -0700	[thread overview]
Message-ID: <20200322012220.Y-EvF7Agt%akpm@linux-foundation.org> (raw)
In-Reply-To: <20200321181954.c0564dfd5514cd742b534884@linux-foundation.org>

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.git.chris@chrisdown.name
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>
Acked-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
@@ -2339,7 +2339,7 @@ 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)
_

  parent reply	other threads:[~2020-03-22  1:22 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-22  1:19 incoming Andrew Morton
2020-03-22  1:22 ` [patch 01/10] memcg: fix NULL pointer dereference in __mem_cgroup_usage_unregister_event Andrew Morton
2020-03-22  1:22 ` [patch 02/10] mm/hotplug: fix hot remove failure in SPARSEMEM|!VMEMMAP case Andrew Morton
2020-03-22  1:22 ` [patch 03/10] page-flags: fix a crash at SetPageError(THP_SWAP) Andrew Morton
2020-03-22  1:22 ` Andrew Morton [this message]
2020-03-22  1:22 ` [patch 05/10] mm, memcg: throttle allocators based on ancestral memory.high Andrew Morton
2020-03-22  1:22 ` [patch 06/10] mm: do not allow MADV_PAGEOUT for CoW pages Andrew Morton
2020-03-22  1:22   ` Andrew Morton
2020-03-22  1:22 ` [patch 07/10] epoll: fix possible lost wakeup on epoll_ctl() path Andrew Morton
2020-03-22  1:22 ` [patch 08/10] mm/mmu_notifier: silence PROVE_RCU_LIST warnings Andrew Morton
2020-03-22  1:22 ` [patch 09/10] mm, slub: prevent kmalloc_node crashes and memory leaks Andrew Morton
2020-03-22  1:22   ` Andrew Morton
2020-03-22  1:22 ` [patch 10/10] x86/mm: split vmalloc_sync_all() Andrew Morton
2020-03-22  1:39 ` + tools-testing-selftests-vm-mlock2-tests-fix-mlock2-false-negative-errors.patch added to -mm tree Andrew Morton
2020-03-22  4:39 ` + libfs-fix-infoleak-in-simple_attr_read.patch " Andrew Morton
2020-03-22  4:41 ` + bus-mhi-fix-printk-format-for-size_t.patch " Andrew Morton

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200322012220.Y-EvF7Agt%akpm@linux-foundation.org \
    --to=akpm@linux-foundation.org \
    --cc=chris@chrisdown.name \
    --cc=guro@fb.com \
    --cc=hannes@cmpxchg.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mhocko@kernel.org \
    --cc=mm-commits@vger.kernel.org \
    --cc=natechancellor@gmail.com \
    --cc=stable@vger.kernel.org \
    --cc=tj@kernel.org \
    --cc=torvalds@linux-foundation.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.