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[209.85.220.65]) by mx.google.com with SMTPS id u8-v6sor1123444pfd.50.2018.06.20.20.07.42 for (Google Transport Security); Wed, 20 Jun 2018 20:07:43 -0700 (PDT) Received-SPF: pass (google.com: domain of baijiaju1990@gmail.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=TghLfkHh; spf=pass (google.com: domain of baijiaju1990@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=baijiaju1990@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=BlI6sZ67WAPyiOAfEubsTr6KMfHjrMipPMRsWQXJc3k=; b=TghLfkHhWYW4CwOlqK7TFn4cWjaZf1kOZwQW5vaM03ST7LRYT5M9lgDkMNLQtrxZF+ prppjXovV8tpYVB9sfrdmx03N3HQ6s9yblgQ6TD+AmY0MURicwMZc0O0RTx7v8fd+WNp 13w+CPTeE/0Evx4//Ii/xLvVOjrx3yvXGPe2NzTtZSFk/8OyaKNxmJV7pisn6p6TS1BW AMMm9nt6iiMIeWoSl/oI6MxdXzEChIA2ZRw9M501QZgn/pT/ic43XsC5QtNaSNtvbMgv v1YU6YtmrPwv1h1uQ0DKgVJv7SVfgs6rJWn35zw3YetUl5dgI17n6sSvMCRh97TawdqH 0PJg== X-Google-Smtp-Source: ADUXVKJPZQIh9pHA0WOSsqwXcZva5fB9jX5MSOEPgz8ZGdaInDSZ5k4rvTiJVYTgtGS12kRJIIyneg== X-Received: by 2002:a62:4a0c:: with SMTP id x12-v6mr25567975pfa.142.1529550462769; Wed, 20 Jun 2018 20:07:42 -0700 (PDT) Received: from oslab.tsinghua.edu.cn ([2402:f000:1:4413:35c0:9e91:c7fc:672]) by smtp.gmail.com with ESMTPSA id o66-v6sm6296117pfi.157.2018.06.20.20.07.40 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 20 Jun 2018 20:07:42 -0700 (PDT) From: Jia-Ju Bai To: akpm@linux-foundation.org, dvyukov@google.com, gregkh@linuxfoundation.org, jthumshirn@suse.de, pombredanne@nexb.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Jia-Ju Bai Subject: [PATCH] mm: mempool: Fix a possible sleep-in-atomic-context bug in mempool_resize() Date: Thu, 21 Jun 2018 11:07:14 +0800 Message-Id: <20180621030714.10368-1-baijiaju1990@gmail.com> X-Mailer: git-send-email 2.17.0 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: X-Virus-Scanned: ClamAV using ClamSMTP The kernel may sleep with holding a spinlock. The function call path (from bottom to top) in Linux-4.16.7 is: [FUNC] remove_element(GFP_KERNEL) mm/mempool.c, 250: remove_element in mempool_resize mm/mempool.c, 247: _raw_spin_lock_irqsave in mempool_resize To fix this bug, GFP_KERNEL is replaced with GFP_ATOMIC. This bug is found by my static analysis tool (DSAC-2) and checked by my code review. Signed-off-by: Jia-Ju Bai --- mm/mempool.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/mempool.c b/mm/mempool.c index 5c9dce34719b..d33bd5d622e7 100644 --- a/mm/mempool.c +++ b/mm/mempool.c @@ -247,7 +247,7 @@ int mempool_resize(mempool_t *pool, int new_min_nr) spin_lock_irqsave(&pool->lock, flags); if (new_min_nr <= pool->min_nr) { while (new_min_nr < pool->curr_nr) { - element = remove_element(pool, GFP_KERNEL); + element = remove_element(pool, GFP_ATOMIC); spin_unlock_irqrestore(&pool->lock, flags); pool->free(element, pool->pool_data); spin_lock_irqsave(&pool->lock, flags);