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=1794537448; b=YrCQcebi9V4MKNFZ+ID4w671ujzNvKGTvtKZFGh+Fg4a/pF9Ifc72dKwsJXVKQSsncii bIGyfGdkxELeYoq8RImSEnwaaoipH732tgvdRm6y4Y4dZQO8pIY5yaWJ6fRrpH0RjJlgc AJl1IcrM7+VlZvYypAUlo/Ry3vWYJaySp5511sSSVoKI60J3WLR1nO0X6fo+E1jiBFZBK cBiVZ5e32PRJQOLpRvlvWmWugvqmdjuumx7joPZptYfilIgLv+tpYEaExibwkcs2UWqg8 snWuS0foYeV6aBMMMhK77CZgNRtG+OgauJfppxlZL57c5k3sXHnZvQTF0VFGVWLOqQQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794537448; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-Id: In-Reply-To:References:X-Mailer:Mime-Version:Content-Type: Content-Transfer-Encoding; bh=c7xVO+NmGklllKi/pnNJQ5f6BZkQyZyz+72UU6VKSbA=; b=UCsf9yzVMzQvbu3Rt0M06tV+e4POlPCUQhcDEhPamean/wIFAdquKiwFap7chiTptUdr WV7Xn1dI6OPcO9aUgz6VSfLcFns2MRAlXaGCafZAhrBow+4qMNw0V+96P3fxusu04ieid N3/MMwnfWrUwaIw6Yfje/jBJQG1Ahl5V8aFuA+cmTCm4gWSfOD1Qm7DMfjRCtXkx3zfMv e7XDduMEtaAC3oRc3frcHML2U0+1izfqGTPmi24O8+m4cFVBg+Vda6p2AOi08YkUagjA3 Tv4pujTBFjVhfswoNbACEZHYRHfs4m83anJKsFXe9bQk1V4h7A4hr5h35ess17I0Aog== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=korg header.b=HDvZ6ex5; 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 BD0C3606A31C; Fri, 13 Nov 2026 02:37:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=korg header.b=HDvZ6ex5 Received: by smtp.kernel.org (Postfix) with ESMTPSA id D32821F000C4; Fri, 13 Nov 2026 02:37:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1794537448; bh=c7xVO+NmGklllKi/pnNJQ5f6BZkQyZyz+72UU6VKSbA=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=HDvZ6ex5mndLiwSybBItN1+QPlX1KOoZqAvJ+RsPkPLPX828lEASG07GMcjmVOP7w wNOxlWkKtT+wuid9MBOoC0w06gT4wqs6y4+6qvmSIIuoUH6VfKZ2f9WPXChjWfM5uH h4QCONLhbPu7nyc6ogBQJGTRB9wYoKrq3vJmHaHo= Date: Thu, 12 Nov 2026 18:37:27 -0800 From: Andrew Morton To: "Adrian Huang (Lenovo)" Cc: Suren Baghdasaryan , Lorenzo Stoakes , "Liam R . Howlett" , Vlastimil Babka , Jann Horn , Pedro Falcato , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, ahuang12@lenovo.com Subject: Re: [PATCH mm-unstable 1/1] fs/proc/task_mmu: advance seq_file position on interrupted VMA lookup Message-Id: <20261112183727.68afda9533aff699eea12cdd@linux-foundation.org> In-Reply-To: <20261112140101.647-1-adrianhuang0701@gmail.com> References: <20261112140101.647-1-adrianhuang0701@gmail.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Thu, 12 Nov 2026 22:01:01 +0800 "Adrian Huang (Lenovo)" wrote: > Commit 5631da56c9a8 ("fs/proc/task_mmu: read proc/pid/maps under > per-vma lock") introduced the possibility of returning -EINTR > from proc_get_vma() when the VMA lookup is interrupted. OK, but what's causing the interruption? > When this happens in m_next(), proc_get_vma() returns an error > pointer without updating the position index. Consequently, > seq_read_iter() reports: > > seq_file: buggy .next function m_next did not update position index > > The above buggy message is reproduced by the following command: > > # stress-ng --vma 0 -t 60 afaict "stress-ng -t" can send SIGALRM, but mmap_read_lock_killable() only responds to fatal signals. So please clarify: exactly what is causing this to happen?