From nobody Wed Oct 8 00:45:55 2025 Received: from mail-pl1-f182.google.com (mail-pl1-f182.google.com [209.85.214.182]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4B0C557C9F; Thu, 3 Jul 2025 13:00:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.182 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751547639; cv=none; b=lrvfeLS6LNjHB2tGIcakBsu7fFKg/JerLb6h8gKKomF6PON6RvZm+0ceHk1pMRRJyC1qeRQDGVBhDKQYiODGT9eekgZEprFJiT+Dt0UryVqyV2Q6vp4aqyr0TpAnemTGfiH4guF0jl/stVNQNclk4bLI4YJP9Vt4mmk6snCNk8k= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751547639; c=relaxed/simple; bh=WZkAFyjn/O80qVQ7Sb4assuy2vAO2IP9Wi6bKPzORVo=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=pkeVX/QS+QgZVTFWlxTllhfkDFuU3dR7ayORPQe95C1p/xkdoV+ewf8f/KXtWxC53dO38qCbCImlvW9OEWf8hDmipN5GqMcN7p4b7ojNtyzfLnfr7fSc8bVNqhlzqdhTFXdD2h/hqIyLQYuuS99xxu8Y6UQItu6h4RL06UwoEJA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=htTeRnzZ; arc=none smtp.client-ip=209.85.214.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="htTeRnzZ" Received: by mail-pl1-f182.google.com with SMTP id d9443c01a7336-236377f00easo67884365ad.1; Thu, 03 Jul 2025 06:00:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1751547637; x=1752152437; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=+V9/b+CRzGm0ij32xv/mNYvSmebJP/k00QdwusN4ULA=; b=htTeRnzZZJY5SH48G3XeuvToGDkJMapkGOSQjvrfkDqFvPqUJKPow+0Vo8AInKV3h6 nDV1QVwWUSBHVaJIaeD44yR/r2KAqyQqjeCF4mbGA7u/U+TA+KdrscIVazzYIxBAWOyC f++vhQgbVSn5Vc9dbQed3Eb45sRbBEfpL5JHIir4rc2GKiP7rhFhJBBToVvGIKZYLBgr q13qDj2Rb7jMx0m+KPaNTA5sVw2eHQMYzijv7fW51tDTyZmfO0b/ZQWSQANCZ0ujf2T+ zAKcGw6gd/DnZFk74KNdTTjyhWjdOyKBa6/ebA+8dTvOn0RptZB7yrQ/5EMeKdcjWwfW +Hxg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1751547637; x=1752152437; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=+V9/b+CRzGm0ij32xv/mNYvSmebJP/k00QdwusN4ULA=; b=trMf+ozpmc0cZW/hph6FOg+znk//Ciuj7oqVVURmxBGsnJcAwvABsTtI410vccDcjL UyYIUKlwzYcS4RQFae5pJMOYPizoyCMHsRIq2Lm9DDoyEH0AIXr3dumknqkWojWEUg9A 14r/daNNYi8Vh71rZLISNhnRH6Z4L7LcXAT/Kyx+iFaXthXtPVoEperW7bMcM1trPv1A vk+3D/b944dHVb2LpPDuqv83y4HKLyqBAwXUfXqsxetfG8HCD1F7dtb4mcPiflFC8DsS Go09rGkuUObnMxm1GVrV+CHcX/MFLJzpmwbtjIDen5SQiL9ArvNqMhWPDnX35kL/udpq Uweg== X-Forwarded-Encrypted: i=1; AJvYcCXkMlchJIqaODm3K81VefWwomgEGurbUI5a5tUX9+NB9KvRC0lsL+el6z5RKRQrOv94rj819fPMC3OTtaY=@vger.kernel.org X-Gm-Message-State: AOJu0YwP+8Ncu9l+KKak7veFxFB4LH6V21rU2N5AnOg6D6Y/mpmrabYO UacnAMg3FpOvKoO/qLbwCWQj2b7zyIVmpBvi8ECPXF4nMzJXh1gukMMyQiP3T9yS2pU= X-Gm-Gg: ASbGncsvBMZ7SruLWJl/ce2OJs90TRoG8Pw/MzIFITR1ga8G+MJcd2hDuFEmhj/B/hQ 1SyZWGw+bXlJ8HdMver5e+n5o7n+vpOEIhQOuN7ny6nW3fjg7X5mxIhNZvSyBNmXXu0MBKZJ2PJ 9/rCKMbr3BfRIc+tP3ZoXOU1Sv/x8tndVF8nckZ1hVdtDx9ChpeDPTem3rWCBCxJqVR9oxv0grg GyGEUTKyv/Dvqf8dMbjhxhYVyXUNoHDiJBpxasR0y+wSscj+n2nfeMeaJ5G1BZ+cavKpyamrV4m cyWFsTSCNPIerVGxLlMx4P1p6Q9IDYwcoysPIl3YSXeAfBj+WmkOgJ7kvfz/Xldvld3hdYY4nu/ b X-Google-Smtp-Source: AGHT+IFnS4sUDe612i/mziOiSd8eMOHyas6kczjurdDjVmc8V2M7FS1CkSHh17LwoanozUJYLQIDPg== X-Received: by 2002:a17:903:1a67:b0:235:a9b:21e0 with SMTP id d9443c01a7336-23c795742fbmr52192025ad.0.1751547636725; Thu, 03 Jul 2025 06:00:36 -0700 (PDT) Received: from localhost.localdomain ([121.185.186.233]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-23c71c3e272sm34161445ad.215.2025.07.03.06.00.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Jul 2025 06:00:35 -0700 (PDT) From: Jeongjun Park To: stable@vger.kernel.org Cc: urezki@gmail.com, akpm@linux-foundation.org, edumazet@google.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Jeongjun Park Subject: [PATCH 6.15.y v2] mm/vmalloc: fix data race in show_numa_info() Date: Thu, 3 Jul 2025 22:00:07 +0900 Message-ID: <20250703130007.16755-1-aha310510@gmail.com> X-Mailer: git-send-email 2.47.2 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" commit 5c5f0468d172ddec2e333d738d2a1f85402cf0bc upstream. The following data-race was found in show_numa_info(): =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D 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 =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D 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 --- mm/vmalloc.c | 63 +++++++++++++++++++++++++++++----------------------- 1 file changed, 35 insertions(+), 28 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 00cf1b575c89..3fb534dcf14d 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -3100,7 +3100,7 @@ static void clear_vm_uninitialized_flag(struct vm_str= uct *vm) /* * 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 &=3D ~VM_UNINITIALIZED; @@ -4934,28 +4934,29 @@ bool vmalloc_dump_obj(void *object) #endif =20 #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 =3D m->private; - unsigned int step =3D 1U << vm_area_page_order(v); =20 - 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 =3D 1U << vm_area_page_order(v); =20 - if (v->flags & VM_UNINITIALIZED) - return; - /* Pair with smp_wmb() in clear_vm_uninitialized_flag() */ - smp_rmb(); + if (!counters) + return; =20 - memset(counters, 0, nr_node_ids * sizeof(unsigned int)); + memset(counters, 0, nr_node_ids * sizeof(unsigned int)); =20 - for (nr =3D 0; nr < v->nr_pages; nr +=3D step) - counters[page_to_nid(v->pages[nr])] +=3D step; - for_each_node_state(nr, N_HIGH_MEMORY) - if (counters[nr]) - seq_printf(m, " N%u=3D%u", nr, counters[nr]); - } + for (nr =3D 0; nr < v->nr_pages; nr +=3D step) + counters[page_to_nid(v->pages[nr])] +=3D step; + for_each_node_state(nr, N_HIGH_MEMORY) + if (counters[nr]) + seq_printf(m, " N%u=3D%u", nr, counters[nr]); } =20 static void show_purge_info(struct seq_file *m) @@ -4983,6 +4984,10 @@ static int vmalloc_info_show(struct seq_file *m, voi= d *p) struct vmap_area *va; struct vm_struct *v; int i; + unsigned int *counters; + + if (IS_ENABLED(CONFIG_NUMA)) + counters =3D kmalloc(nr_node_ids * sizeof(unsigned int), GFP_KERNEL); =20 for (i =3D 0; i < nr_vmap_nodes; i++) { vn =3D &vmap_nodes[i]; @@ -4999,6 +5004,11 @@ static int vmalloc_info_show(struct seq_file *m, voi= d *p) } =20 v =3D va->vm; + if (v->flags & VM_UNINITIALIZED) + continue; + + /* Pair with smp_wmb() in clear_vm_uninitialized_flag() */ + smp_rmb(); =20 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_file *m, void= *p) if (is_vmalloc_addr(v->pages)) seq_puts(m, " vpages"); =20 - 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_file *m, vo= id *p) * As a final step, dump "unpurged" areas. */ show_purge_info(m); + if (IS_ENABLED(CONFIG_NUMA)) + kfree(counters); return 0; } =20 static int __init proc_vmalloc_init(void) { - void *priv_data =3D NULL; - - if (IS_ENABLED(CONFIG_NUMA)) - priv_data =3D 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); --