From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 EBB972E2F0D; Tue, 8 Jul 2025 16:55:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751993746; cv=none; b=WQJ7rFYrjr43bmmP5LON6l8EO+BSqCnvBDiZiA1Ethx9IsSvSpCUuFPkvd+q90vEhm7uy+Q/edZQAVrIH0pzUd252MBttwZxQJD4CM7q69M6dVgkGW2cfFUNO3GhkieZuAxaLH/c/moY/5nnmrCDqBVsPBPA14Gz26SdrUAf/KM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751993746; c=relaxed/simple; bh=IlIohNjIY9eD8ep4Zh4wME0mh6oKJ24XSgC3N+uoTGU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fV9KgdjLaeXESBHTCTbZX7SAz9jVn97/xYAxoAnrFvV0slTkPkXvE4L6UgRRTbxZDxqeXRjxZULuO7j9mhI/5Yuj9caO81W1F3pMiL50T3hgdS6JkMpo2HhcUgGcrJYthH32H1FFE52gu4DGW8kdPaUhoYPzqhlUYT7zNapGzxQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=H413k3Cv; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="H413k3Cv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 30C0AC4CEED; Tue, 8 Jul 2025 16:55:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1751993745; bh=IlIohNjIY9eD8ep4Zh4wME0mh6oKJ24XSgC3N+uoTGU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=H413k3Cvl7eUPOgMmVYCJAl8OiEaaZiT6/a1whjXQ6u5Bw+KQHh76XcwbI3/MifaP 97Jlg5ZgGSUf9mnGVGDlx72VL3zHCjtDGY/y+lUtM5VFQBZrUg5I8uRQhLLSGppiZz yXMT7UqnnvHD3sEIRUXnRVeJy10Ue8YAWcWNLhvY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jeongjun Park , Eric Dumazet , Andrew Morton , "Uladzislau Rezki (Sony)" Subject: [PATCH 6.15 172/178] mm/vmalloc: fix data race in show_numa_info() Date: Tue, 8 Jul 2025 18:23:29 +0200 Message-ID: <20250708162240.946538446@linuxfoundation.org> X-Mailer: git-send-email 2.50.0 In-Reply-To: <20250708162236.549307806@linuxfoundation.org> References: <20250708162236.549307806@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jeongjun Park commit 5c5f0468d172ddec2e333d738d2a1f85402cf0bc upstream. The following data-race was found in show_numa_info(): ================================================================== BUG: KCSAN: data-race in vmalloc_info_show / vmalloc_info_show read to 0xffff88800971fe30 of 4 bytes by task 8289 on cpu 0: show_numa_info mm/vmalloc.c:4936 [inline] vmalloc_info_show+0x5a8/0x7e0 mm/vmalloc.c:5016 seq_read_iter+0x373/0xb40 fs/seq_file.c:230 proc_reg_read_iter+0x11e/0x170 fs/proc/inode.c:299 .... write to 0xffff88800971fe30 of 4 bytes by task 8287 on cpu 1: show_numa_info mm/vmalloc.c:4934 [inline] vmalloc_info_show+0x38f/0x7e0 mm/vmalloc.c:5016 seq_read_iter+0x373/0xb40 fs/seq_file.c:230 proc_reg_read_iter+0x11e/0x170 fs/proc/inode.c:299 .... value changed: 0x0000008f -> 0x00000000 ================================================================== According to this report,there is a read/write data-race because m->private is accessible to multiple CPUs. To fix this, instead of allocating the heap in proc_vmalloc_init() and passing the heap address to m->private, vmalloc_info_show() should allocate the heap. Link: https://lkml.kernel.org/r/20250508165620.15321-1-aha310510@gmail.com Fixes: 8e1d743f2c26 ("mm: vmalloc: support multiple nodes in vmallocinfo") Signed-off-by: Jeongjun Park Suggested-by: Eric Dumazet Suggested-by: Andrew Morton Reviewed-by: "Uladzislau Rezki (Sony)" Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- mm/vmalloc.c | 63 ++++++++++++++++++++++++++++++++--------------------------- 1 file changed, 35 insertions(+), 28 deletions(-) --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -3100,7 +3100,7 @@ static void clear_vm_uninitialized_flag( /* * Before removing VM_UNINITIALIZED, * we should make sure that vm has proper values. - * Pair with smp_rmb() in show_numa_info(). + * Pair with smp_rmb() in vread_iter() and vmalloc_info_show(). */ smp_wmb(); vm->flags &= ~VM_UNINITIALIZED; @@ -4934,28 +4934,29 @@ bool vmalloc_dump_obj(void *object) #endif #ifdef CONFIG_PROC_FS -static void show_numa_info(struct seq_file *m, struct vm_struct *v) -{ - if (IS_ENABLED(CONFIG_NUMA)) { - unsigned int nr, *counters = m->private; - unsigned int step = 1U << vm_area_page_order(v); - if (!counters) - return; +/* + * Print number of pages allocated on each memory node. + * + * This function can only be called if CONFIG_NUMA is enabled + * and VM_UNINITIALIZED bit in v->flags is disabled. + */ +static void show_numa_info(struct seq_file *m, struct vm_struct *v, + unsigned int *counters) +{ + unsigned int nr; + unsigned int step = 1U << vm_area_page_order(v); - if (v->flags & VM_UNINITIALIZED) - return; - /* Pair with smp_wmb() in clear_vm_uninitialized_flag() */ - smp_rmb(); + if (!counters) + return; - memset(counters, 0, nr_node_ids * sizeof(unsigned int)); + memset(counters, 0, nr_node_ids * sizeof(unsigned int)); - for (nr = 0; nr < v->nr_pages; nr += step) - counters[page_to_nid(v->pages[nr])] += step; - for_each_node_state(nr, N_HIGH_MEMORY) - if (counters[nr]) - seq_printf(m, " N%u=%u", nr, counters[nr]); - } + for (nr = 0; nr < v->nr_pages; nr += step) + counters[page_to_nid(v->pages[nr])] += step; + for_each_node_state(nr, N_HIGH_MEMORY) + if (counters[nr]) + seq_printf(m, " N%u=%u", nr, counters[nr]); } static void show_purge_info(struct seq_file *m) @@ -4983,6 +4984,10 @@ static int vmalloc_info_show(struct seq_ struct vmap_area *va; struct vm_struct *v; int i; + unsigned int *counters; + + if (IS_ENABLED(CONFIG_NUMA)) + counters = kmalloc(nr_node_ids * sizeof(unsigned int), GFP_KERNEL); for (i = 0; i < nr_vmap_nodes; i++) { vn = &vmap_nodes[i]; @@ -4999,6 +5004,11 @@ static int vmalloc_info_show(struct seq_ } v = va->vm; + if (v->flags & VM_UNINITIALIZED) + continue; + + /* Pair with smp_wmb() in clear_vm_uninitialized_flag() */ + smp_rmb(); seq_printf(m, "0x%pK-0x%pK %7ld", v->addr, v->addr + v->size, v->size); @@ -5033,7 +5043,9 @@ static int vmalloc_info_show(struct seq_ if (is_vmalloc_addr(v->pages)) seq_puts(m, " vpages"); - show_numa_info(m, v); + if (IS_ENABLED(CONFIG_NUMA)) + show_numa_info(m, v, counters); + seq_putc(m, '\n'); } spin_unlock(&vn->busy.lock); @@ -5043,19 +5055,14 @@ static int vmalloc_info_show(struct seq_ * As a final step, dump "unpurged" areas. */ show_purge_info(m); + if (IS_ENABLED(CONFIG_NUMA)) + kfree(counters); return 0; } static int __init proc_vmalloc_init(void) { - void *priv_data = NULL; - - if (IS_ENABLED(CONFIG_NUMA)) - priv_data = kmalloc(nr_node_ids * sizeof(unsigned int), GFP_KERNEL); - - proc_create_single_data("vmallocinfo", - 0400, NULL, vmalloc_info_show, priv_data); - + proc_create_single("vmallocinfo", 0400, NULL, vmalloc_info_show); return 0; } module_init(proc_vmalloc_init);