From nobody Sat Feb 7 15:09:55 2026 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 8241A2374E for ; Mon, 5 Feb 2024 14:15:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707142513; cv=none; b=L/jhz5xJIpfnWayL5BZpw878M1H4eDTi/W2yqIwlnto5Pd1hIaM4laW5cHRgI67fnOi+71y0Gp9dufWCp36aEt+9GPXfUrMZJAIIcAR4euMl3hw7cjWAzdx1CM2gfoBv10q6WJ83oG7mfyoFXE9/bXptaW6LgBo4DG+XUS45fzM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707142513; c=relaxed/simple; bh=iqDeabfWw4JAl1GsXp6xX7i80knJmS9R0n4Vk6rDw10=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition; b=FVnFVL/WGooTJUWq/Qt8uKuNKESHajtxCM8fLj9MUsymVEUrJXiQmrl28Ra05Z3VRQUPk4O5QLIlZPQWhNLr7gfm5iT5Wy8I6al6dRemRJ5yZMJJgk1Ki9qcg9vbSQACIfypIoqEZd5Tyb+LhlQGdwnwvYqj4mRIZy6r+w18Wy8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=a/gSCdSr; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="a/gSCdSr" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1707142510; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type; bh=11pxIPHjBBl92wQMC3DFzCqQJYEHlgWDIYJq9X2o8Gc=; b=a/gSCdSruePTTeg4NkAWMk0n2XnKuYdqvmFKp4jGl5bXCxvLWduVwxRDKeWpcYIcY3Mnm0 as1A3/b6lXooSn04G9Il14HOgaNfEBQtuQ53RHKrcb+Jv4e1VodogscGfmIJ1/C/dGxHE/ dciO8LWdptfKlt/Ui5qu5p6eCbnrzu0= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-640-WEhRXOPpNoGlqpJ5BlKlMw-1; Mon, 05 Feb 2024 09:15:06 -0500 X-MC-Unique: WEhRXOPpNoGlqpJ5BlKlMw-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 50C2EB42B26; Mon, 5 Feb 2024 14:15:06 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.45.225.165]) by smtp.corp.redhat.com (Postfix) with SMTP id 1979C2166B31; Mon, 5 Feb 2024 14:15:04 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Mon, 5 Feb 2024 15:13:50 +0100 (CET) Date: Mon, 5 Feb 2024 15:13:48 +0100 From: Oleg Nesterov To: Christian Brauner Cc: Andy Lutomirski , "Eric W. Biederman" , Tycho Andersen , linux-kernel@vger.kernel.org Subject: [PATCH] pidfd: change do_notify_pidfd() to use __wake_up(poll_to_key(EPOLLIN)) Message-ID: <20240205141348.GA16539@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.6 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" rather than wake_up_all(). This way do_notify_pidfd() won't wakeup the POLLHUP-only waiters which wait for pid_task() =3D=3D NULL. TODO: - as Christian pointed out, this asks for the new wake_up_all_poll() helper, it can already have other users. - we can probably discriminate the PIDFD_THREAD and non-PIDFD_THREAD waiters, but this needs more work. See https://lore.kernel.org/all/20240205140848.GA15853@redhat.com/ Signed-off-by: Oleg Nesterov Reviewed-by: Tycho Andersen --- kernel/signal.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/kernel/signal.c b/kernel/signal.c index 9b40109f0c56..c3fac06937e2 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2021,11 +2021,12 @@ int send_sigqueue(struct sigqueue *q, struct pid *p= id, enum pid_type type) =20 void do_notify_pidfd(struct task_struct *task) { - struct pid *pid; + struct pid *pid =3D task_pid(task); =20 WARN_ON(task->exit_state =3D=3D 0); - pid =3D task_pid(task); - wake_up_all(&pid->wait_pidfd); + + __wake_up(&pid->wait_pidfd, TASK_NORMAL, 0, + poll_to_key(EPOLLIN | EPOLLRDNORM)); } =20 /* --=20 2.25.1.362.g51ebf55