From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C8FFF218592; Mon, 28 Sep 2026 22:34:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790634880; cv=none; b=FQkWPwc6A/rs0cXzeG1pg11SoyevJrdDU8Aq5oYUq4l6dPeDkoAsfp7PPs7WCUw1l0lyOXYm1uNZ6DjwnZEqVKckEfBmBHuxUO+MBAlCfu+kFJ3u0PsXMSt6S6NUbwTE76U+rMbuEhb+JHEFnbgXLn2BnxpzBsdOl7gb50IMoS8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790634880; c=relaxed/simple; bh=lUdR03ciUJHWptADdFwWN8mGqjaPBnQo1aUmIo2lBh8=; h=Date:To:From:Subject:Message-Id; b=o7/e5F9R79o1ykqfu8UPiBKdCwK2c8Gx5t7c75s5UG7RLpOKaf7m8QXtUQUmAzh1u3dHammusXmd/9Xp96C87DbbwLPCuY30XG1264L6iySSmlN3qEBmaD8OK7qRH+1YknNaTAF58F7XzCPzvjJRls2V2LdOmx82qZ+Hr8FKCQs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=JvId+d8n; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="JvId+d8n" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3A7901F000FF; Mon, 28 Sep 2026 22:34:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1790634878; bh=sKjePeqCrtKbM6G/X/meOkomsmYHGJ7GiOkFQnbn81I=; h=Date:To:From:Subject; b=JvId+d8nWEvfnskZjs3AdHOyGnpuCJz+7xU0Ll8o91z8qmkjVvuOyry1LsYrTURPx WeGI01lNPtSPrb7GmRpNUPHXP2Umrj3OFAA1AWVkQ74IDZshYIlMSW1XJ8kG+cZPxR k7O0h2aSk0AV9lX5/lI23nrLOGP76mPI/2EVE8WA= Date: Mon, 28 Sep 2026 15:34:37 -0700 To: mm-commits@vger.kernel.org,stable@vger.kernel.org,sj@kernel.org,donggeunyoo.kernel@gmail.com,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-damon-core-prevent-size-quota-overflow-in-the-temporal-goal-tuner.patch added to mm-new branch Message-Id: <20260928223438.3A7901F000FF@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm/damon/core: prevent size quota overflow in the temporal goal tuner has been added to the -mm mm-new branch. Its filename is mm-damon-core-prevent-size-quota-overflow-in-the-temporal-goal-tuner.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-damon-core-prevent-size-quota-overflow-in-the-temporal-goal-tuner.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. The mm-new branch of mm.git is not included in linux-next If a few days of testing in mm-new is successful, the patch will me moved into mm.git's mm-unstable branch, which is included in linux-next Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: Donggeun Yoo Subject: mm/damon/core: prevent size quota overflow in the temporal goal tuner Date: Mon, 28 Sep 2026 01:48:14 -0700 Patch series "mm/damon: fix the temporal goal tuner's size quota conversion", v5. damos_goal_tune_esz_bp_temporal() hands the size quota to damos_set_effective_quota() through quota->esz_bp in basis points, and the multiply that gets it there is unchecked. On 32-bit it wraps above 429496 bytes, and a wrapped product below 10000 divides to a zero effective quota. damos_quota_is_full() is then true on the first test of every charge window, so the scheme makes no progress for as long as the goal is unachieved. Patch 1 bounds the conversion. Patch 2 pins the boundary in the core kunit suite, where the new test would fail without patch 1 on any word size. This patch (of 2): damos_goal_tune_esz_bp_temporal() converts the scheme's size quota into basis points with "quota->esz_bp = quota->sz * 10000", both unsigned long, and damos_set_effective_quota() divides the result back by 10000. quotas/bytes is unbounded; bytes_store() hands it to kstrtoul() as is. On 32-bit the product wraps for any size quota above ULONG_MAX / 10000, that is 429496 bytes. A wrapped product below 10000 divides to a zero effective quota: 429497 gives 0. damos_quota_is_full() is then true on the first test of every charge window. Other wrapped values are wrong without being zero: 500000 gives 70503. Triggering this needs a scheme with a quota goal, the temporal goal tuner, and a size quota above ULONG_MAX / 10000 -- 429496 bytes on 32-bit, 1844674407370955 on 64-bit. The scheme then makes no progress for as long as the goal is unachieved, which is easy to notice, and writing a smaller size quota restores it. Nothing is corrupted and nothing leaks. This is unlikely to be hit on a tested setup. addr_unit does not cover this. It only scales the numbers a paddr context writes to quotas/bytes, so a large enough scaled value wraps just the same, and vaddr and fvaddr contexts take raw byte values. Bound the multiply. Link: https://lore.kernel.org/20260928084816.5575-1-sj@kernel.org Link: https://lore.kernel.org/20260928084816.5575-2-sj@kernel.org Fixes: af738a6a00c1 ("mm/damon/core: introduce DAMOS_QUOTA_GOAL_TUNER_TEMPORAL") Signed-off-by: Donggeun Yoo Signed-off-by: SJ Park Signed-off-by: Andrew Morton Reviewed-by: SJ Park Cc: # 7.1.x --- mm/damon/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/damon/core.c~mm-damon-core-prevent-size-quota-overflow-in-the-temporal-goal-tuner +++ a/mm/damon/core.c @@ -3291,7 +3291,7 @@ static void damos_goal_tune_esz_bp_tempo if (score >= 10000) quota->esz_bp = 0; - else if (quota->sz) + else if (quota->sz && quota->sz <= ULONG_MAX / 10000) quota->esz_bp = quota->sz * 10000; else quota->esz_bp = ULONG_MAX; _ Patches currently in -mm which might be from donggeunyoo.kernel@gmail.com are userfaultfd-clear-the-inherited-uffd-bit-in-move_swap_pte.patch selftests-mm-add-tests-for-uffdio_move-of-a-uffd-protected-swap-entry.patch mm-damon-core-charge-only-the-part-of-a-region-the-filter-left.patch mm-damon-tests-core-kunit-test-the-size-charged-for-a-filter-trimmed-region.patch mm-damon-core-prevent-size-quota-overflow-in-the-temporal-goal-tuner.patch mm-damon-tests-core-kunit-test-the-temporal-tuners-size-quota-conversion.patch