From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from canpmsgout12.his.huawei.com (canpmsgout12.his.huawei.com [113.46.200.227]) (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 47CB231B833; Tue, 1 Sep 2026 02:42:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=113.46.200.227 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788230537; cv=none; b=iF1Ts3wisRnmonKKHE6DX/jOcsBZVHqb7whYbyRQnlbrPTkANKpvHCjVkI6JwxCNXBpKhjQ9I7UYoJWLLWu9f8CMV61I4eE0gSoKOLCux7jICNQqHgzUyvA+xWdmNrbhxOGAvTVLmAWk7XRoLwMjMgdjLZc2Z4OZt9H6ImmFfK4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788230537; c=relaxed/simple; bh=6PIg64GDnvklPC0UJj5Fh9eYgMI0rQUBw8ZYe1++kd8=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=nDMVsJ+YApbeEJN7j4OiKw77ImKQIapl27Ul6w36KvZsoyVDMpDpQt/sjqvXjUYMPUn3f5ycuu4xkBp1IC3HI9clxkXEZ0ORxJmaa5Uf2rYaEMj3p5QqMUSEFiWwnJHVOFSRsJTJdyIDhmVA339xz/Bj+/wUIgYJwjs3R5/p6lY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.b=c9mLb8sr; arc=none smtp.client-ip=113.46.200.227 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.b="c9mLb8sr" dkim-signature: v=1; a=rsa-sha256; d=huawei.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=J4yJnyqxeHRcmq2Fv8EZ0jwzeTlaVGzNrqh5hfCP6Nw=; b=c9mLb8srEPPPQLn8yQD0c0BDviwcWNS55C5KXhKc4Lr6mNPUZ/QWJP9W/S2+92FK4d3gHgR/6 obYTqC6R8LtPGNDKBwX3FscPqdzkyNC5H6hczFGuWxwrAZrZMKArEzgEpCM04d+2arVNeGGvtZ7 9YQTydYIvXdK+e7T86kwZ34= Received: from mail.maildlp.com (unknown [172.19.163.200]) by canpmsgout12.his.huawei.com (SkyGuard) with ESMTPS id 4hYqbY22jCznTVx; Tue, 1 Sep 2026 10:30:49 +0800 (CST) Received: from dggpemf500011.china.huawei.com (unknown [7.185.36.131]) by mail.maildlp.com (Postfix) with ESMTPS id 3CFF64055B; Tue, 1 Sep 2026 10:42:03 +0800 (CST) Received: from huawei.com (10.90.53.73) by dggpemf500011.china.huawei.com (7.185.36.131) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Tue, 1 Sep 2026 10:42:01 +0800 From: Jinjie Ruan To: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH v2 05/12] pidfs: Use test_bit_acquire() for attr flag tests Date: Tue, 1 Sep 2026 10:42:27 +0800 Message-ID: <20260901024234.135119-6-ruanjinjie@huawei.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260901024234.135119-1-ruanjinjie@huawei.com> References: <20260901024234.135119-1-ruanjinjie@huawei.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: kwepems200001.china.huawei.com (7.221.188.67) To dggpemf500011.china.huawei.com (7.185.36.131) Replace test_bit() + smp_rmb() with test_bit_acquire() for PIDFS_ATTR_BIT_EXIT and PIDFS_ATTR_BIT_COREDUMP tests in pidfd_info(). The acquire semantics ensure that if the flag is observed set, the associated attr fields written before smp_wmb() + set_bit() are also visible. Writers keep smp_wmb() + set_bit() since no release bitop exists. Cc: Alexander Viro Cc: Christian Brauner Cc: Jan Kara Assisted-by: DeepSeek:DeepSeek-V3 Signed-off-by: Jinjie Ruan --- fs/pidfs.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/fs/pidfs.c b/fs/pidfs.c index a6a643f15d08..2cd0fab73180 100644 --- a/fs/pidfs.c +++ b/fs/pidfs.c @@ -393,8 +393,7 @@ static long pidfd_info(struct file *file, unsigned int cmd, unsigned long arg) attr = READ_ONCE(pid->attr); if (mask & PIDFD_INFO_EXIT) { - if (test_bit(PIDFS_ATTR_BIT_EXIT, &attr->attr_mask)) { - smp_rmb(); + if (test_bit_acquire(PIDFS_ATTR_BIT_EXIT, &attr->attr_mask)) { kinfo.mask |= PIDFD_INFO_EXIT; #ifdef CONFIG_CGROUPS kinfo.cgroupid = attr->cgroupid; @@ -405,8 +404,7 @@ static long pidfd_info(struct file *file, unsigned int cmd, unsigned long arg) } if (mask & PIDFD_INFO_COREDUMP) { - if (test_bit(PIDFS_ATTR_BIT_COREDUMP, &attr->attr_mask)) { - smp_rmb(); + if (test_bit_acquire(PIDFS_ATTR_BIT_COREDUMP, &attr->attr_mask)) { kinfo.mask |= PIDFD_INFO_COREDUMP | PIDFD_INFO_COREDUMP_SIGNAL | PIDFD_INFO_COREDUMP_CODE; kinfo.coredump_mask = attr->coredump_mask; kinfo.coredump_signal = attr->coredump_signal; -- 2.34.1