From patchwork Wed Sep 11 13:14:07 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oleg Nesterov X-Patchwork-Id: 13800514 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 B50B91714AC for ; Wed, 11 Sep 2024 13:14:33 +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=1726060475; cv=none; b=FLPILfT6gDZdQN/pYyhQyhc2wrpGtwoyG4f2/UvYRVPnzf5JPF5rLgAEcIKt4HzLFXb7g8hhW8OKDOpbLQTpUZq/l6x/xqNWCSA5oEvQO3O7QzdzfuD1daUeurcctBogCt/gcVShDM1ALtqmaN3qkYiarapNdkUbo3SA945nt/k= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726060475; c=relaxed/simple; bh=xMCskwQcfEwOUbdWrAErBf7MWGcAi69GXyrTD2rmklQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=rFwz4dr2JTJMLUU9MjOs2rvPuwUKgrBLYqBfuBAD8B3ZstVgomFykmv1+g6v5SvXhAd3wQSvDzbTlhU3rD/2E2G+Z746NmOrcZkB12ChZfb3g0rdKakPQDJG4B9GD6LCqJTGNbnpuUTSpUqX6hHX5nhNNAZecy9cfJLd2EF1Cmc= 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=ZyxDge5y; 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="ZyxDge5y" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1726060472; 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=V7W3kDXSwt1yeFb/GkUq9ycOOE066CsELW4k/XSqo1U=; b=ZyxDge5yv/Q92NderNonKJEloPRo49wbyCg4UHv3urH6FsfTUtRCNzzdIstPJVcTYvmgdK eP1z758wDGuNkA7BZswJledkVrN6+UkEC+oxLqgIGVhmAcR2qr5IIpMbB9jLAnuNQRtxpO jGhQk8L0njCah/VNL1JmZEgZ/4xcZAk= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-592-UdEgacnvMGaY4T7ugj50_g-1; Wed, 11 Sep 2024 09:14:29 -0400 X-MC-Unique: UdEgacnvMGaY4T7ugj50_g-1 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (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-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id A48B9197700E; Wed, 11 Sep 2024 13:14:26 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.45.225.229]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id 85A893001D11; Wed, 11 Sep 2024 13:14:19 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Wed, 11 Sep 2024 15:14:15 +0200 (CEST) Date: Wed, 11 Sep 2024 15:14:07 +0200 From: Oleg Nesterov To: Sven Schnelle , Andrew Morton Cc: Michael Ellerman , Masami Hiramatsu , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , "Liang, Kan" , Linus Torvalds , Andrii Nakryiko , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: [PATCH -mm 2/3] uprobes: introduce the global struct vm_special_mapping xol_mapping Message-ID: <20240911131407.GB3448@redhat.com> References: <20240903073629.2442754-1-svens@linux.ibm.com> <20240911131320.GA3448@redhat.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20240911131320.GA3448@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Currently each xol_area has its own instance of vm_special_mapping, this is suboptimal and ugly. Kill xol_area->xol_mapping and add a single global instance of vm_special_mapping, the ->fault() method can use area->pages rather than xol_mapping->pages. As a side effect this fixes the problem introduced by the recent commit 223febc6e557 ("mm: add optional close() to struct vm_special_mapping"), if special_mapping_close() is called from the __mmput() paths, it will use vma->vm_private_data = &area->xol_mapping freed by uprobe_clear_state(). Reported-by: Sven Schnelle Closes: https://lore.kernel.org/all/yt9dy149vprr.fsf@linux.ibm.com/ Fixes: 223febc6e557 ("mm: add optional close() to struct vm_special_mapping") Signed-off-by: Oleg Nesterov --- kernel/events/uprobes.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 73cc47708679..a478e028043f 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -99,7 +99,6 @@ struct xol_area { atomic_t slot_count; /* number of in-use slots */ unsigned long *bitmap; /* 0 = free slot */ - struct vm_special_mapping xol_mapping; struct page *pages[2]; /* * We keep the vma's vm_start rather than a pointer to the vma @@ -1433,6 +1432,21 @@ void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned lon set_bit(MMF_RECALC_UPROBES, &vma->vm_mm->flags); } +static vm_fault_t xol_fault(const struct vm_special_mapping *sm, + struct vm_area_struct *vma, struct vm_fault *vmf) +{ + struct xol_area *area = vma->vm_mm->uprobes_state.xol_area; + + vmf->page = area->pages[0]; + get_page(vmf->page); + return 0; +} + +static const struct vm_special_mapping xol_mapping = { + .name = "[uprobes]", + .fault = xol_fault, +}; + /* Slot allocation for XOL */ static int xol_add_vma(struct mm_struct *mm, struct xol_area *area) { @@ -1459,7 +1473,7 @@ static int xol_add_vma(struct mm_struct *mm, struct xol_area *area) vma = _install_special_mapping(mm, area->vaddr, PAGE_SIZE, VM_EXEC|VM_MAYEXEC|VM_DONTCOPY|VM_IO, - &area->xol_mapping); + &xol_mapping); if (IS_ERR(vma)) { ret = PTR_ERR(vma); goto fail; @@ -1498,9 +1512,6 @@ static struct xol_area *__create_xol_area(unsigned long vaddr) if (!area->bitmap) goto free_area; - area->xol_mapping.name = "[uprobes]"; - area->xol_mapping.fault = NULL; - area->xol_mapping.pages = area->pages; area->pages[0] = alloc_page(GFP_HIGHUSER); if (!area->pages[0]) goto free_bitmap;