From nobody Fri Jul 24 23:30:48 2026 Received: from m16.mail.163.com (m16.mail.163.com [220.197.31.4]) (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 F27B23B4E8F for ; Wed, 22 Jul 2026 09:27:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.31.4 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784712460; cv=none; b=YCBZnt6TCxqawCn67cJSpALQs2MsiosJyH3j0B6SsoF2UFxfIN42YYgFt41HUEjkaIwdmOUnlVbhaBKrGlR/SV33n0l/EMExDIj25MZ6uJZDIVUGjjKK4B9Qcttws7o0R3C+NqzpK+fxI/NhbRvXBiBd2pezUaCneGXQduPHQvs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784712460; c=relaxed/simple; bh=0f3c94uKgHFqF35xbTvB/HfgZyTd59v9o3PWTpi/JVM=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=DUTC17den5CfeG166qiDmVR+gRYkTjg/BthxmtXgjjqA87BHAE0uaQ/x++iXQc9/Xz4xg93mmxMYvi/K7Yaq0rd2Av8I18JHo2idJLdExI5MF9hgUvjOZn7jfYCheUjuvduhs052BvhUedkGlzkTX2yWy2jud3ZvPT2ai7bONV4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=MN0DeUOD; arc=none smtp.client-ip=220.197.31.4 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="MN0DeUOD" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:To:Subject:Date:Message-Id:MIME-Version; bh=mV yLNtcGFqMMWAIWtW4iF3YkvbkdX3ti+Cv8fxWpraw=; b=MN0DeUOD+aEyWHPmlW kazmak+3lAYeVpgtu3OzsL008hzGtLjQOTa72pKvCrABiqUa5bLDXriq0+rd8roR bK92IC+zXjWQpPssugOS9gFjjbXhwPFk32pNDGwYTmyO+okYYtxJPJI1MwNuD8KQ uuBUbgnaytJPeH5vkH0nU/9XA= Received: from pc.localdomain (unknown []) by gzga-smtp-mtada-g1-3 (Coremail) with SMTP id _____wAH3YXUjGBqP_nGJg--.117S2; Wed, 22 Jul 2026 17:26:46 +0800 (CST) From: Jiale Yao To: Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Jiale Yao Subject: [PATCH] mm/page_idle: call folio_test_lru() after folio_get() Date: Wed, 22 Jul 2026 17:26:42 +0800 Message-Id: <20260722092642.1123347-1-yaojiale02@163.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: _____wAH3YXUjGBqP_nGJg--.117S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7tr48Xr15trW7Zry5CF1rWFg_yoW8XFW7pF ZxKw1DJFykJa47C347JFnxZF1Fk39xXay5GFW3Ww43Z3W5t3WUKFWxKw15Za4fG3ykAa40 vayDAFy0vF1UAF7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0pRR6wJUUUUU= X-CM-SenderInfo: x1dryxhdohiji6rwjhhfrp/xtbC8BYLRWpgjNbK5gAA3U Content-Type: text/plain; charset="utf-8" page_idle_get_folio() speculatively calls folio_test_lru() before folio_try_get(). The folio can get freed and reallocated to a tail page in the meantime. In that case, VM_BUG_ON_PGFLAGS() in const_folio_flags() can be triggered. Remove the speculative call. Also mark the folio_test_lru() check right after folio_try_get() success as no more unlikely. This is a sibling-path bug: damon_get_folio() was copied from this function with the same flawed pattern. Commit d6b8b02a27b3 ("mm/damon/ops-common: call folio_test_lru() after folio_get()") fixed damon_get_folio(), but page_idle_get_folio() was left unfixed. KCSAN (strict mode) confirms the data race on the folio flags: BUG: KCSAN: data-race in ... / percpu_counter_add_batch page_idle_get_folio+0x7a/0x2d0 page_idle_bitmap_read+0xc9/0x220 Signed-off-by: Jiale Yao Reviewed-by: Lorenzo Stoakes (ARM) Reviewed-by: SJ Park --- mm/page_idle.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/page_idle.c b/mm/page_idle.c index 9c67cbac2965..29ee18f0e8ce 100644 --- a/mm/page_idle.c +++ b/mm/page_idle.c @@ -40,9 +40,9 @@ static struct folio *page_idle_get_folio(unsigned long pf= n) return NULL; =20 folio =3D page_folio(page); - if (!folio_test_lru(folio) || !folio_try_get(folio)) + if (!folio_try_get(folio)) return NULL; - if (unlikely(page_folio(page) !=3D folio || !folio_test_lru(folio))) { + if (unlikely(page_folio(page) !=3D folio) || !folio_test_lru(folio)) { folio_put(folio); folio =3D NULL; } --=20 2.34.1