From nobody Sun Feb 8 20:32:46 2026 Received: from mail-oo1-f71.google.com (mail-oo1-f71.google.com [209.85.161.71]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B345C319852 for ; Tue, 16 Dec 2025 10:22:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.71 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765880556; cv=none; b=exg1anK2HdahiDrssAHRXVn3Vjm8e5x4g/v7aM5aYTr1RK9teduVNpMAvvmLTriMeHNUL8HPu0j6/OAXVr0xF5TXnlX2rnWSGWQsS/6AvwCF3/8MUWnWY8whGpSBh5V6i5rid/WrnhAmb9RoETGhrz+ORBz0tRNvt2gmVtJ2KWQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765880556; c=relaxed/simple; bh=UcuV1CGzN2Yjvm/wKuKxPszLbFRtAAkfpu4x3YLX6nU=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=C9MBHg0wG9bydaVdaa6G+S2AjAg0A/WpBc0+HptUlSzocnfac4/X6/iu2mhTHQq0x8/bcRDidkMmlrP3UhUmXvjrMXvhT4O97OdSiDFsqyecpc4G9TqKOVCR/V3wVXqQvyUL3Bq0MGaYOSyZbQLmBRXuBMpYdVOkpPuJ4KCe4UU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.161.71 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oo1-f71.google.com with SMTP id 006d021491bc7-65b153371efso6982737eaf.1 for ; Tue, 16 Dec 2025 02:22:34 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1765880553; x=1766485353; h=to:from:subject:message-id:in-reply-to:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=Engptsff3CFYqiyQv/RO29+UUu/8wFL/ph8vj/jIFVY=; b=rXmFlaEAYmNfEGzvVjZcL7hwRFBrF5422hOvWVWckoN1af1Fs5qU3Wn32ft0LeyTl0 mj5gMbTBJXagEnQcQ9Dl4INex2DVPvTbl55Z0KZv0n4u1injZW1lCbvbPV4Iz4v0jISv thuSMaLmkSpOgW5obN4MKxePNEnf58Wa91bzW0H8CcqZoO6M0SauV4JuNKRzxweRHCct 5G/dOhOOnmtELJDcF8upbiCoel15cMTuU1OvcIAgn2P6NA9cEN8DMaicWPEijRiBzgpl 5JXr08S7VDNzzgGQhFxnj2TNIL1H/AkYyXSVpfpj1iiQZW5mkhqqcPbyhZzvAub1SWJv E0Qg== X-Gm-Message-State: AOJu0YyARpyJJlhdzHMvM9AzdJkyJvEon4CoRqIC6KPioy4TfMaLCg2S RKoCPuX636nmhSLKoUG+2cWG1cytOFKak0L9p3HaAsVxUX7kfB/UYnGxYOrHUCLBlxzaOmlAxkq l71RtKfcIaTY8tEPhMy1Aed5KHv9/yAAZxOlDH2RmgahMmKPIF+dPxdhI064= X-Google-Smtp-Source: AGHT+IGg7vyOROZiNA8g8tBGeNN6adfOFCsccbeDxOPrpuGGtFSXwSfdUGQ52v9QRR26ZDTIC1mEXOTroH2j9R2RuAFJW4Vfjutu Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a4a:d390:0:b0:65b:2d2f:a179 with SMTP id 006d021491bc7-65b37e8550dmr6517732eaf.2.1765880553693; Tue, 16 Dec 2025 02:22:33 -0800 (PST) Date: Tue, 16 Dec 2025 02:22:33 -0800 In-Reply-To: <69410b4b.a70a0220.104cf0.0347.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <694132e9.a70a0220.33cd7b.0138.GAE@google.com> Subject: Forwarded: [PATCH] nfsd: fix percpu_ref leak when nfsd_net_up is false From: syzbot To: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" For archival purposes, forwarding an incoming command email to linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com. *** Subject: [PATCH] nfsd: fix percpu_ref leak when nfsd_net_up is false Author: kartikey406@gmail.com #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git= master When nfsd_destroy_serv() is called without any threads being started, nfsd_startup_net() was never invoked, so nfsd_net_up remains false. In this case, nfsd_shutdown_net() returns early without calling percpu_ref_exit() to free the percpu reference initialized in nfsd_create_serv(). This causes two memory leaks per call: - 8 bytes of percpu memory (the reference counter) - 64 bytes of slab memory (the percpu_ref_data structure) Fix this by calling percpu_ref_exit() in the early return path when nfsd_net_up is false. Reported-by: syzbot+6ee3b889bdeada0a6226@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=3D6ee3b889bdeada0a6226 Fixes: 47e988147f40 ("nfsd: add nfsd_serv_try_get and nfsd_serv_put") Signed-off-by: Deepanshu Kartikey --- fs/nfsd/nfssvc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c index b08ae85d53ef..00c6a0c96885 100644 --- a/fs/nfsd/nfssvc.c +++ b/fs/nfsd/nfssvc.c @@ -406,8 +406,10 @@ static void nfsd_shutdown_net(struct net *net) { struct nfsd_net *nn =3D net_generic(net, nfsd_net_id); =20 - if (!nn->nfsd_net_up) + if (!nn->nfsd_net_up) { + percpu_ref_exit(&nn->nfsd_net_ref); return; + } =20 percpu_ref_kill_and_confirm(&nn->nfsd_net_ref, nfsd_net_done); wait_for_completion(&nn->nfsd_net_confirm_done); --=20 2.43.0