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 B7D6A3D5649 for ; Tue, 17 Mar 2026 13:58:25 +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=1773755906; cv=none; b=cQS/ioBzcfLVkrllm9CUB9CjpDg4cvQv2ayb1rbansCtfheA2EIVuXMerYd1D7PutWTOgsaFlX8F06h+T980SgRtChTkV4j0kDiSYN/kHkQUw2WwQDH/p+jEwKqbDZCDmZWU5fMTvirg7UAj9esIuiw37MBQJs4yTeNbQ8ZXVpI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773755906; c=relaxed/simple; bh=QmrhnXT/D44sHmmVxIuWIdhCxEv3Y2dA7eye+Zegq3o=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=R9vpW5/bML9qabhcIpQkcyqPDdJBoSWsypaDIbgJV0aSpcS+tMsmFSBr9rh0vSO5Wu4nXg4YXIaE5uW/u8q64T/eAIlprEVgJA/i5Kve+WbSIEwcvsCt6tEWmt54OGB0BE5lNzebOd/6QB0i8FnKaTkHJKh9RqniJW+Z2AUVwPA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine 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=jILUuEv0; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine 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="jILUuEv0" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1773755904; 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=CjnQmRkU/l3UkgRwp+/DaDM7NsRFp28HdJQYirkFQAo=; b=jILUuEv0JCdQCVGHqXwh2xsVBh1id8oKezsUMbeDfCPBzAG672s+8rmzTY6AdiYny0s0E/ Pj34aHbdpvY4aSSDhSP9O3PKjZjFOVtmPo2Ibws6C/30ke6MMZ1lrVtHRGcT0yRSq1GCwk udJSCArDm3CfSV2BOXHBsSQivz81LUE= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-459-fBy6XB6YM-C6LUV4Vt7LRg-1; Tue, 17 Mar 2026 09:58:23 -0400 X-MC-Unique: fBy6XB6YM-C6LUV4Vt7LRg-1 X-Mimecast-MFC-AGG-ID: fBy6XB6YM-C6LUV4Vt7LRg_1773755902 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (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 mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id E8A2A1800245; Tue, 17 Mar 2026 13:58:21 +0000 (UTC) Received: from fedora (unknown [10.45.225.204]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id 2742219560B1; Tue, 17 Mar 2026 13:58:19 +0000 (UTC) Received: by fedora (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Tue, 17 Mar 2026 14:58:21 +0100 (CET) Date: Tue, 17 Mar 2026 14:58:18 +0100 From: Oleg Nesterov To: Andrew Morton , Deepanshu Kartikey Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH -mm v2] do_notify_parent: sanitize the valid_signal() checks Message-ID: References: <20260316151956.563558-1-kartikey406@gmail.com> 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-Disposition: inline In-Reply-To: <20260316151956.563558-1-kartikey406@gmail.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Now that kernel_clone() checks valid_signal(args->exit_signal), the "sig" argument of do_notify_parent() must always be valid or we have a bug. However, do_notify_parent() only checks that sig != -1 at the start, then it does another valid_signal() check before __send_signal_locked(). This is confusing. Change do_notify_parent() to WARN and return early if valid_signal(sig) is false. Signed-off-by: Oleg Nesterov --- kernel/signal.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/signal.c b/kernel/signal.c index 86aad7badb9a..683ef92f7234 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2171,7 +2171,8 @@ bool do_notify_parent(struct task_struct *tsk, int sig) bool autoreap = false; u64 utime, stime; - WARN_ON_ONCE(sig == -1); + if (WARN_ON_ONCE(!valid_signal(sig))) + return false; /* do_notify_parent_cldstop should have been called instead. */ WARN_ON_ONCE(task_is_stopped_or_traced(tsk)); @@ -2252,7 +2253,7 @@ bool do_notify_parent(struct task_struct *tsk, int sig) * Send with __send_signal as si_pid and si_uid are in the * parent's namespaces. */ - if (valid_signal(sig) && sig) + if (sig) __send_signal_locked(sig, &info, tsk->parent, PIDTYPE_TGID, false); __wake_up_parent(tsk, tsk->parent); spin_unlock_irqrestore(&psig->siglock, flags); -- 2.52.0