From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794426573; b=kcLkMVCBmYcTFYhsz7jacYgPDZ3tGW2rxH3sNxNhTz7xJlLMjrWm/TBUym5BxGTldQyD 94J8CtMonGGrj3oT4YgAej0mojU+V9HfRSMMhlpYLVSxVDc+/W64WgJtfESnzc1L/2KSA JLfGFsvF1rKsRitAvLL+oacdqq+RQXZOk/hZmlbO/JGm9E8ci5sgt0COvMx/fsA05A54X B4zc1bXFOQ5DIrRksRrDcr+QdUg1XAQ0rwkbjkkraA2O+4kLdNFUUsh7By8s0xdqmyWkR yKNdCC86KfyOiGyGaQO7qTnZz4GHCYRsxkIGhUKoVAYov4TLw+snAh9hB6AjFHJfKcw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794426573; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=Oc6ejAXbOWvHTL82rIpVWqGj664xm50y5XMfyuasBD4=; b=EnZ22c3Xua2aLeaItMQcYK3J8llkf/y8PhA+PoxUQrhw/AKpumyZwKhfSUrn3Dc5JzXc UIuCU3wwAJol8eOdYX6i0Vzw8cQ0LVJ4wt4FETVunwVEafHs0eD+hTHBj/IgcxaDi1VGk dGKjptOQxSC2c1XiRr6roXuD6BH5bS5WE+pehZSA5W7hDgAWlvq8YcdxbLbbuVoz6P8lf ZHzBiYASsQNMeeKca6Wctgk/G9tnRE5y/rqpSPv/dEAJscAi9DrIjgET666rbOvkYS0AE 2CHsrPad6TwYbx4EAuzEGVGentblijExxYmlP9ETf+CMGj/0LRMYAxrGcZ/XZ03z/lw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=RVU7pDRI; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 24B20606A324 for ; Wed, 11 Nov 2026 19:49:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=RVU7pDRI Received: by smtp.kernel.org (Postfix) with ESMTPSA id B90E31F00A05; Wed, 11 Nov 2026 19:49:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794426572; bh=Oc6ejAXbOWvHTL82rIpVWqGj664xm50y5XMfyuasBD4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=RVU7pDRIZmN7g1hdECpmXx4OGKYHOvrSRSUO4Hu3SLEPh2QLP42T8rVFVp2QYsywV Vg2eIimGlCSH0JfwpisHUOfo+EWbUZm0Pwy25O476tSsGB6KheserOKE1Rfnd7tDpV KwF64w3DawSWmGuf33fAUobEL+Ed02rZcurGiZS5X4U1wOqLMmaErtaahFZIbx2oak pxq+NnxmAueaMR2msNuNZx3WRbFSi5nXojxokNxKYn3eOGySB5XMNFq1xV5GBeZljA HntG0VowicFMWri+orrxZI+Bq8oBTC6HoJyWeTA13Qydzwxr0fd6YuI6uLF6AQoj5d avszLxfswRGig== From: Sasha Levin To: stable@vger.kernel.org Cc: Rik van Riel , Michal Hocko , Shakeel Butt , Andrew Morton , Johannes Weiner , Muchun Song , Roman Gushchin , Sasha Levin Subject: [PATCH 6.12.y] mm/memcontrol: fix stuck FLUSHING_CACHED_CHARGE bit on isolated cpus Date: Wed, 11 Nov 2026 14:49:30 -0500 Message-ID: <20261111194854.4009938-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261107051931-failed-6.12-d2f28a1a652e@kernel.org> References: <20261107051931-failed-6.12-d2f28a1a652e@kernel.org> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Rik van Riel [ Upstream commit d2f28a1a652e0a43f6f63de9b4e4d8d5f2716803 ] When drain_all_stock() sets FLUSHING_CACHED_CHARGE before checking isolation, schedule_drain_work() can drop the work in a separate RCU critical section, and housekeeping_update()'s synchronize_rcu() can race that second check, leaving the flag set. drain_local_stock() only clears the bit for work that ran, so the flag remains set and the stock is never drained again. Have schedule_drain_work() return whether the work was queued, and clear FLUSHING_CACHED_CHARGE in drain_all_stock() when the remote CPU is isolated, so future drains can retry. Link: https://lore.kernel.org/20260828135036.7d44361f@fangorn Fixes: 6a792697a53a ("memcg: do not drain charge pcp caches on remote isolated cpus") Suggested-by: Michal Hocko Suggested-by: Shakeel Butt Signed-off-by: Rik van Riel Signed-off-by: Andrew Morton Acked-by: Shakeel Butt Acked-by: Michal Hocko Cc: Johannes Weiner Cc: Muchun Song Cc: Roman Gushchin Cc: [ sashal: Adapted schedule_drain_work() result handling to an inline branch in drain_all_stock() for the combined charge cache. ] Signed-off-by: Sasha Levin --- mm/memcontrol.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 4d1caa4faf69f..e5a4ec28f4955 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1871,6 +1871,8 @@ void drain_all_stock(struct mem_cgroup *root_memcg) drain_local_stock(&stock->work); else if (!cpu_is_isolated(cpu)) schedule_work_on(cpu, &stock->work); + else + clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags); } } migrate_enable(); -- 2.53.0