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[195.135.220.15]) by mx.google.com with ESMTPS id d13si405552ejj.242.2019.05.17.05.47.59 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 17 May 2019 05:48:00 -0700 (PDT) Received-SPF: softfail (google.com: domain of transitioning mhocko@kernel.org does not designate 195.135.220.15 as permitted sender) client-ip=195.135.220.15; Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning mhocko@kernel.org does not designate 195.135.220.15 as permitted sender) smtp.mailfrom=mhocko@kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id BBF60AF59; Fri, 17 May 2019 12:47:59 +0000 (UTC) Date: Fri, 17 May 2019 14:47:59 +0200 From: Michal Hocko To: Konstantin Khlebnikov Cc: linux-mm@kvack.org, Andrew Morton , linux-kernel@vger.kernel.org, Cyrill Gorcunov , Kirill Tkhai , Al Viro Subject: Re: [PATCH 4/5] proc: use down_read_killable for /proc/pid/clear_refs Message-ID: <20190517124759.GD1825@dhcp22.suse.cz> References: <155790967258.1319.11531787078240675602.stgit@buzz> <155790968147.1319.10247444846354273332.stgit@buzz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <155790968147.1319.10247444846354273332.stgit@buzz> User-Agent: Mutt/1.10.1 (2018-07-13) 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: On Wed 15-05-19 11:41:21, Konstantin Khlebnikov wrote: > Replace the only unkillable mmap_sem lock in clear_refs_write. Poor changelog again. The change itself looks ok to me. > Signed-off-by: Konstantin Khlebnikov > --- > fs/proc/task_mmu.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > index 78bed6adc62d..7f84d1477b5b 100644 > --- a/fs/proc/task_mmu.c > +++ b/fs/proc/task_mmu.c > @@ -1140,7 +1140,10 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf, > goto out_mm; > } > > - down_read(&mm->mmap_sem); > + if (down_read_killable(&mm->mmap_sem)) { > + count = -EINTR; > + goto out_mm; > + } > tlb_gather_mmu(&tlb, mm, 0, -1); > if (type == CLEAR_REFS_SOFT_DIRTY) { > for (vma = mm->mmap; vma; vma = vma->vm_next) { -- Michal Hocko SUSE Labs