From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 5B64440DFD6 for ; Sun, 26 Apr 2026 10:49:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777200580; cv=none; b=NEukBh8VfCuK9vc25bA/ypkAOeieP6OfpecNslvg5zfi7Oo4X4ryLE0u5ZRaAYwMSwHelDXDcfOvREy8dK0RaUnGWT5rlTcd3hsKVScPnsEKsMT4wU9/6cVJtCLgLUN2Q4Zdnx4Fm/RXjv/Yv5wSurl87tPW3b+E+H2RaTw5QFw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777200580; c=relaxed/simple; bh=L1nbLO0Xj7/K8G+R19OFJ/yJuZU2dwzW1RcyM4ouWPU=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=KWnJJwOrC4SiokIAUDodUezk+hPAQOX7Z7SQE0Df4B0b4dj3tE74JkBkKJ/Xn6AJ8nnM5CHrMwGSPdx+5wKa86MlYfq2FD0Q/+3ZsJ76WIWsKybgUZyo452uS5sJz0tpgFwd6lHtg5y42E234wjmHbkLshHrjEpQ20Z9Z11i/BI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=FCWhKPr+; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="FCWhKPr+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9261BC2BCAF; Sun, 26 Apr 2026 10:49:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1777200579; bh=L1nbLO0Xj7/K8G+R19OFJ/yJuZU2dwzW1RcyM4ouWPU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=FCWhKPr+x/+OaHV3MpHuliUX7bbExsb2uYJYnKRtVWVy4rl0Nv8eVMX24Xbq19L9o AAnb3kFvhj2UigzwT9nWAugGbRwWKuiAwz8lsknVS1eItkpd3oFKo9YG6WSsTdAM7L FZI2jBVtYW1kqjslfJJtvI+qEGwq5SjujJ4ofF4o= Date: Sun, 26 Apr 2026 03:49:38 -0700 From: Andrew Morton To: syzbot Cc: Liam.Howlett@oracle.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, ljs@kernel.org, shakeel.butt@linux.dev, surenb@google.com, syzkaller-bugs@googlegroups.com, vbabka@kernel.org, Muchun Song , Qi Zheng Subject: Re: [syzbot] [mm?] WARNING: bad unlock balance in do_wp_page Message-Id: <20260426034938.db29d74982a8eb8463f8cf3a@linux-foundation.org> In-Reply-To: <69edca15.170a0220.38e3f1.0000.GAE@google.com> References: <69edca15.170a0220.38e3f1.0000.GAE@google.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Sun, 26 Apr 2026 01:17:25 -0700 syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 6596a02b2078 Merge tag 'drm-next-2026-04-22' of https://gi.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=12483702580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=24c8da4692f901cb > dashboard link: https://syzkaller.appspot.com/bug?extid=7d60b33a8a546263da7c > compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 > userspace arch: i386 > > Unfortunately, I don't have any reproducer for this issue yet. argh, that dreaded sentence. Thanks. Something's definitely amiss. This is at least the fifth report of rcu_read_lock() imbalance post-7.0. Others: https://lore.kernel.org/69eab803.a00a0220.17a17.004a.GAE@google.com https://lore.kernel.org/69eab803.a00a0220.17a17.004b.GAE@google.com https://lore.kernel.org/69eafb0e.a00a0220.9259.0031.GAE@google.com https://lore.kernel.org/69ebcbe2.a00a0220.7773.0005.GAE@google.com In some cases we released it too often, in other cases we failed to release it. The first one is slightly more useful in that it tells us that the not-released rcu_read_lock() was taken in folio_lruvec_lock_irqsave(). Muchun & Qi: you played with that rcu locking in 31b54a5e8916. Can you please double-check that we didn't miss something?