From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 B4B6A3838B for ; Fri, 9 Feb 2024 13:08:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707484096; cv=none; b=iCxmsg6Yb5VHDhSzZzqX7WRRthDOmqASelxtTy/OPVmRBUAUf/S5op/3nSihQmiKKnQrx7aCwIXUHW0XUiJlsefqGW3PmKeSWCLfWrS1M4MKT+NVxBopxWIruw4Ri949/5QvDF4Mer33Px3XXU0kCfbAyx+ntbJ+eE8XCfz2sxA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707484096; c=relaxed/simple; bh=mHSlaxGCUJKdSq3oGHFsskIaS1mOF+ZiEDyOYY36WmA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=jzePYSMukCh/o0TfyFSAYyXlBQr+Esc+12ymDCQHmWhDDapL65N/tI3p5JmEieRAwJA+dDlttN1leDZQiyrB2LIUyTrLMgfa/+oXmfE5D4MOxOuAs4JaK4AJluqRzw4j0tQYDIBiDa/f1vS82/Ion9u50AmENgcSQRWgNmk30qQ= 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=RaZ5+HYW; arc=none smtp.client-ip=170.10.129.124 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="RaZ5+HYW" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1707484093; 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: in-reply-to:in-reply-to:references:references; bh=ETbj5B8vI9mqFeC8WBwO1d2T9IgzINe0mXcd/+60DO0=; b=RaZ5+HYWdsGqGHbZxbVPmjprwVjswlZO/HEiD3L1iImAfNh5CmNXCK/DSQe104TkqIt6aY 65BTsxj5rUM0b0uCjGgpJGiN/K7tK2jBgrMc5lk+KzpA4kQMR8kXQA9bEhDFOcwltA9ggs 7MHEVubuUdx32j4icEgGil2ILgHTmQY= 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-197-WKn6s1c9Mxu6tyxh85JWuQ-1; Fri, 09 Feb 2024 08:08:10 -0500 X-MC-Unique: WKn6s1c9Mxu6tyxh85JWuQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (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 A223D83B7E6; Fri, 9 Feb 2024 13:08:09 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.45.226.84]) by smtp.corp.redhat.com (Postfix) with SMTP id 025AC8BCC; Fri, 9 Feb 2024 13:08:07 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Fri, 9 Feb 2024 14:06:53 +0100 (CET) Date: Fri, 9 Feb 2024 14:06:50 +0100 From: Oleg Nesterov To: Christian Brauner Cc: Andy Lutomirski , "Eric W. Biederman" , Tycho Andersen , linux-api@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 2/2] pidfd: change pidfd_send_signal() to respect PIDFD_THREAD Message-ID: <20240209130650.GA8048@redhat.com> References: <20240209130620.GA8039@redhat.com> Precedence: bulk X-Mailing-List: linux-api@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240209130620.GA8039@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.1 Turn kill_pid_info() into kill_pid_info_type(), this allows to pass any pid_type to group_send_sig_info(), despite its name it should work fine even if type = PIDTYPE_PID. Change pidfd_send_signal() to use PIDTYPE_PID or PIDTYPE_TGID depending on PIDFD_THREAD. While at it kill another TODO comment in pidfd_show_fdinfo(). As Christian expains fdinfo reports f_flags, userspace can already detect PIDFD_THREAD. Signed-off-by: Oleg Nesterov --- kernel/fork.c | 2 -- kernel/signal.c | 38 ++++++++++++++++++++++---------------- 2 files changed, 22 insertions(+), 18 deletions(-) diff --git a/kernel/fork.c b/kernel/fork.c index cd61ca87d0e6..47b565598063 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2051,8 +2051,6 @@ static void pidfd_show_fdinfo(struct seq_file *m, struct file *f) seq_put_decimal_ll(m, "Pid:\t", nr); - /* TODO: report PIDFD_THREAD */ - #ifdef CONFIG_PID_NS seq_put_decimal_ll(m, "\nNSpid:\t", nr); if (nr > 0) { diff --git a/kernel/signal.c b/kernel/signal.c index a8199fda0d61..9578ce17d85d 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -47,6 +47,7 @@ #include #include #include +#include #define CREATE_TRACE_POINTS #include @@ -1436,7 +1437,8 @@ void lockdep_assert_task_sighand_held(struct task_struct *task) #endif /* - * send signal info to all the members of a group + * send signal info to all the members of a thread group or to the + * individual thread if type == PIDTYPE_PID. */ int group_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p, enum pid_type type) @@ -1478,7 +1480,8 @@ int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp) return ret; } -int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid) +static int kill_pid_info_type(int sig, struct kernel_siginfo *info, + struct pid *pid, enum pid_type type) { int error = -ESRCH; struct task_struct *p; @@ -1487,11 +1490,10 @@ int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid) rcu_read_lock(); p = pid_task(pid, PIDTYPE_PID); if (p) - error = group_send_sig_info(sig, info, p, PIDTYPE_TGID); + error = group_send_sig_info(sig, info, p, type); rcu_read_unlock(); if (likely(!p || error != -ESRCH)) return error; - /* * The task was unhashed in between, try again. If it * is dead, pid_task() will return NULL, if we race with @@ -1500,6 +1502,11 @@ int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid) } } +int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid) +{ + return kill_pid_info_type(sig, info, pid, PIDTYPE_TGID); +} + static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid) { int error; @@ -3872,14 +3879,10 @@ static struct pid *pidfd_to_pid(const struct file *file) * @info: signal info * @flags: future flags * - * The syscall currently only signals via PIDTYPE_PID which covers - * kill(, . It does not signal threads or process - * groups. - * In order to extend the syscall to threads and process groups the @flags - * argument should be used. In essence, the @flags argument will determine - * what is signaled and not the file descriptor itself. Put in other words, - * grouping is a property of the flags argument not a property of the file - * descriptor. + * Send the signal to the thread group or to the individual thread depending + * on PIDFD_THREAD. + * In the future extension to @flags may be used to override the default scope + * of @pidfd. * * Return: 0 on success, negative errno on failure */ @@ -3890,6 +3893,7 @@ SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig, struct fd f; struct pid *pid; kernel_siginfo_t kinfo; + bool thread; /* Enforce flags be set to 0 until we add an extension. */ if (flags) @@ -3910,6 +3914,8 @@ SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig, if (!access_pidfd_pidns(pid)) goto err; + thread = f.file->f_flags & PIDFD_THREAD; + if (info) { ret = copy_siginfo_from_user_any(&kinfo, info); if (unlikely(ret)) @@ -3925,12 +3931,12 @@ SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig, (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL)) goto err; } else { - prepare_kill_siginfo(sig, &kinfo, SI_USER); + prepare_kill_siginfo(sig, &kinfo, + thread ? SI_TKILL : SI_USER); } - /* TODO: respect PIDFD_THREAD */ - ret = kill_pid_info(sig, &kinfo, pid); - + ret = kill_pid_info_type(sig, &kinfo, pid, + thread ? PIDTYPE_PID : PIDTYPE_TGID); err: fdput(f); return ret; -- 2.25.1.362.g51ebf55