treewide: Use struct_size() for kmalloc()-family

One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:

struct foo {
int stuff;
void *entry[];
};

instance = kmalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);

Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:

instance = kmalloc(struct_size(instance, entry, count), GFP_KERNEL);

This patch makes the changes for kmalloc()-family (and kvmalloc()-family)
uses. It was done via automatic conversion with manual review for the
"CHECKME" non-standard cases noted below, using the following Coccinelle
script:

// pkey_cache = kmalloc(sizeof *pkey_cache + tprops->pkey_tbl_len *
// sizeof *pkey_cache->table, GFP_KERNEL);
@@
identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc";
expression GFP;
identifier VAR, ELEMENT;
expression COUNT;
@@

- alloc(sizeof(*VAR) + COUNT * sizeof(*VAR->ELEMENT), GFP)
+ alloc(struct_size(VAR, ELEMENT, COUNT), GFP)

// mr = kzalloc(sizeof(*mr) + m * sizeof(mr->map[0]), GFP_KERNEL);
@@
identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc";
expression GFP;
identifier VAR, ELEMENT;
expression COUNT;
@@

- alloc(sizeof(*VAR) + COUNT * sizeof(VAR->ELEMENT[0]), GFP)
+ alloc(struct_size(VAR, ELEMENT, COUNT), GFP)

// Same pattern, but can't trivially locate the trailing element name,
// or variable name.
@@
identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc";
expression GFP;
expression SOMETHING, COUNT, ELEMENT;
@@

- alloc(sizeof(SOMETHING) + COUNT * sizeof(ELEMENT), GFP)
+ alloc(CHECKME_struct_size(&SOMETHING, ELEMENT, COUNT), GFP)

Signed-off-by: Kees Cook <[e-mail]>

drivers/clk/bcm/clk-iproc-asiu.c

···
 	if (WARN_ON(!asiu))
 		return;
 
-	asiu->clk_data = kzalloc(sizeof(*asiu->clk_data->hws) * num_clks +
-				 sizeof(*asiu->clk_data), GFP_KERNEL);
+	asiu->clk_data = kzalloc(struct_size(asiu->clk_data, hws, num_clks),
+				 GFP_KERNEL);
 	if (WARN_ON(!asiu->clk_data))
 		goto err_clks;
 	asiu->clk_data->num = num_clks;

drivers/clk/bcm/clk-iproc-pll.c

···
 	if (WARN_ON(!pll))
 		return;
 
-	clk_data = kzalloc(sizeof(*clk_data->hws) * num_clks +
-				sizeof(*clk_data), GFP_KERNEL);
+	clk_data = kzalloc(struct_size(clk_data, hws, num_clks), GFP_KERNEL);
 	if (WARN_ON(!clk_data))
 		goto err_clk_data;
 	clk_data->num = num_clks;

drivers/clk/berlin/bg2.c

···
 	u8 avpll_flags = 0;
 	int n, ret;
 
-	clk_data = kzalloc(sizeof(*clk_data) +
-			   sizeof(*clk_data->hws) * MAX_CLKS, GFP_KERNEL);
+	clk_data = kzalloc(struct_size(clk_data, hws, MAX_CLKS), GFP_KERNEL);
 	if (!clk_data)
 		return;
 	clk_data->num = MAX_CLKS;

drivers/clk/berlin/bg2q.c

···
 	struct clk_hw **hws;
 	int n, ret;
 
-	clk_data = kzalloc(sizeof(*clk_data) +
-			   sizeof(*clk_data->hws) * MAX_CLKS, GFP_KERNEL);
+	clk_data = kzalloc(struct_size(clk_data, hws, MAX_CLKS), GFP_KERNEL);
 	if (!clk_data)
 		return;
 	clk_data->num = MAX_CLKS;

drivers/clk/clk-asm9260.c

···
 	int n;
 	u32 accuracy = 0;
 
-	clk_data = kzalloc(sizeof(*clk_data) +
-			   sizeof(*clk_data->hws) * MAX_CLKS, GFP_KERNEL);
+	clk_data = kzalloc(struct_size(clk_data, hws, MAX_CLKS), GFP_KERNEL);
 	if (!clk_data)
 		return;
 	clk_data->num = MAX_CLKS;

drivers/clk/clk-aspeed.c

···
 	if (!scu_base)
 		return;
 
-	aspeed_clk_data = kzalloc(sizeof(*aspeed_clk_data) +
-			sizeof(*aspeed_clk_data->hws) * ASPEED_NUM_CLKS,
-			GFP_KERNEL);
+	aspeed_clk_data = kzalloc(struct_size(aspeed_clk_data, hws,
+					      ASPEED_NUM_CLKS),
+				  GFP_KERNEL);
 	if (!aspeed_clk_data)
 		return;
 

drivers/clk/clk-clps711x.c

···
 	if (!base)
 		return ERR_PTR(-ENOMEM);
 
-	clps711x_clk = kzalloc(sizeof(*clps711x_clk) +
-			sizeof(*clps711x_clk->clk_data.hws) * CLPS711X_CLK_MAX,
-			GFP_KERNEL);
+	clps711x_clk = kzalloc(struct_size(clps711x_clk, clk_data.hws,
+					   CLPS711X_CLK_MAX),
+			       GFP_KERNEL);
 	if (!clps711x_clk)
 		return ERR_PTR(-ENOMEM);
 

drivers/clk/clk-efm32gg.c

···
 	void __iomem *base;
 	struct clk_hw **hws;
 
-	clk_data = kzalloc(sizeof(*clk_data) +
-			   sizeof(*clk_data->hws) * CMU_MAX_CLKS, GFP_KERNEL);
+	clk_data = kzalloc(struct_size(clk_data, hws, CMU_MAX_CLKS),
+			   GFP_KERNEL);
 
 	if (!clk_data)
 		return;

drivers/clk/clk-gemini.c

···
 	int ret;
 	int i;
 
-	gemini_clk_data = kzalloc(sizeof(*gemini_clk_data) +
-			sizeof(*gemini_clk_data->hws) * GEMINI_NUM_CLKS,
-			GFP_KERNEL);
+	gemini_clk_data = kzalloc(struct_size(gemini_clk_data, hws,
+					      GEMINI_NUM_CLKS),
+				  GFP_KERNEL);
 	if (!gemini_clk_data)
 		return;
 

drivers/clk/clk-stm32h7.c

···
 	const char *hse_clk, *lse_clk, *i2s_clk;
 	struct regmap *pdrm;
 
-	clk_data = kzalloc(sizeof(*clk_data) +
-			sizeof(*clk_data->hws) * STM32H7_MAX_CLKS,
-			GFP_KERNEL);
+	clk_data = kzalloc(struct_size(clk_data, hws, STM32H7_MAX_CLKS),
+			   GFP_KERNEL);
 	if (!clk_data)
 		return;
 

drivers/clk/clk-stm32mp1.c

···
 
 	max_binding =  data->maxbinding;
 
-	clk_data = kzalloc(sizeof(*clk_data) +
-				  sizeof(*clk_data->hws) * max_binding,
-				  GFP_KERNEL);
+	clk_data = kzalloc(struct_size(clk_data, hws, max_binding),
+			   GFP_KERNEL);
 	if (!clk_data)
 		return -ENOMEM;
 

drivers/clk/samsung/clk-exynos-clkout.c

···
 	int ret;
 	int i;
 
-	clkout = kzalloc(sizeof(*clkout) +
-			 sizeof(*clkout->data.hws) * EXYNOS_CLKOUT_NR_CLKS,
+	clkout = kzalloc(struct_size(clkout, data.hws, EXYNOS_CLKOUT_NR_CLKS),
 			 GFP_KERNEL);
 	if (!clkout)
 		return;

drivers/dax/device.c

···
 	if (!count)
 		return ERR_PTR(-EINVAL);
 
-	dev_dax = kzalloc(sizeof(*dev_dax) + sizeof(*res) * count, GFP_KERNEL);
+	dev_dax = kzalloc(struct_size(dev_dax, res, count), GFP_KERNEL);
 	if (!dev_dax)
 		return ERR_PTR(-ENOMEM);
 

drivers/dma/edma.c

···
 		return NULL;
 	}
 
-	edesc = kzalloc(sizeof(*edesc) + sg_len * sizeof(edesc->pset[0]),
-			GFP_ATOMIC);
+	edesc = kzalloc(struct_size(edesc, pset, sg_len), GFP_ATOMIC);
 	if (!edesc)
 		return NULL;
 
···
 			nslots = 2;
 	}
 
-	edesc = kzalloc(sizeof(*edesc) + nslots * sizeof(edesc->pset[0]),
-			GFP_ATOMIC);
+	edesc = kzalloc(struct_size(edesc, pset, nslots), GFP_ATOMIC);
 	if (!edesc)
 		return NULL;
 
···
 		}
 	}
 
-	edesc = kzalloc(sizeof(*edesc) + nslots * sizeof(edesc->pset[0]),
-			GFP_ATOMIC);
+	edesc = kzalloc(struct_size(edesc, pset, nslots), GFP_ATOMIC);
 	if (!edesc)
 		return NULL;
 

drivers/dma/moxart-dma.c

···
 		return NULL;
 	}
 
-	d = kzalloc(sizeof(*d) + sg_len * sizeof(d->sg[0]), GFP_ATOMIC);
+	d = kzalloc(struct_size(d, sg, sg_len), GFP_ATOMIC);
 	if (!d)
 		return NULL;
 

drivers/dma/omap-dma.c

···
 	}
 
 	/* Now allocate and setup the descriptor. */
-	d = kzalloc(sizeof(*d) + sglen * sizeof(d->sg[0]), GFP_ATOMIC);
+	d = kzalloc(struct_size(d, sg, sglen), GFP_ATOMIC);
 	if (!d)
 		return NULL;
 

drivers/dma/sa11x0-dma.c

···
 		}
 	}
 
-	txd = kzalloc(sizeof(*txd) + j * sizeof(txd->sg[0]), GFP_ATOMIC);
+	txd = kzalloc(struct_size(txd, sg, j), GFP_ATOMIC);
 	if (!txd) {
 		dev_dbg(chan->device->dev, "vchan %p: kzalloc failed\n", &c->vc);
 		return NULL;
···
 	if (sglen == 0)
 		return NULL;
 
-	txd = kzalloc(sizeof(*txd) + sglen * sizeof(txd->sg[0]), GFP_ATOMIC);
+	txd = kzalloc(struct_size(txd, sg, sglen), GFP_ATOMIC);
 	if (!txd) {
 		dev_dbg(chan->device->dev, "vchan %p: kzalloc failed\n", &c->vc);
 		return NULL;

drivers/dma/sh/usb-dmac.c

···
 	struct usb_dmac_desc *desc;
 	unsigned long flags;
 
-	desc = kzalloc(sizeof(*desc) + sg_len * sizeof(desc->sg[0]), gfp);
+	desc = kzalloc(struct_size(desc, sg, sg_len), gfp);
 	if (!desc)
 		return -ENOMEM;
 

drivers/firewire/core-topology.c

···
 {
 	struct fw_node *node;
 
-	node = kzalloc(sizeof(*node) + port_count * sizeof(node->ports[0]),
-		       GFP_ATOMIC);
+	node = kzalloc(struct_size(node, ports, port_count), GFP_ATOMIC);
 	if (node == NULL)
 		return NULL;
 

drivers/gpio/gpiolib.c

···
 	if (count < 0)
 		return ERR_PTR(count);
 
-	descs = kzalloc(sizeof(*descs) + sizeof(descs->desc[0]) * count,
-			GFP_KERNEL);
+	descs = kzalloc(struct_size(descs, desc, count), GFP_KERNEL);
 	if (!descs)
 		return ERR_PTR(-ENOMEM);
 

drivers/gpu/drm/nouveau/nvkm/engine/pm/base.c

···
 
 		sdom = spec;
 		while (sdom->signal_nr) {
-			dom = kzalloc(sizeof(*dom) + sdom->signal_nr *
-				      sizeof(*dom->signal), GFP_KERNEL);
+			dom = kzalloc(struct_size(dom, signal, sdom->signal_nr),
+				      GFP_KERNEL);
 			if (!dom)
 				return -ENOMEM;
 

drivers/hwspinlock/omap_hwspinlock.c

···
 
 	num_locks = i * 32; /* actual number of locks in this device */
 
-	bank = kzalloc(sizeof(*bank) + num_locks * sizeof(*hwlock), GFP_KERNEL);
+	bank = kzalloc(struct_size(bank, lock, num_locks), GFP_KERNEL);
 	if (!bank) {
 		ret = -ENOMEM;
 		goto iounmap_base;

drivers/hwspinlock/u8500_hsem.c

···
 	/* clear all interrupts */
 	writel(0xFFFF, io_base + HSEM_ICRALL);
 
-	bank = kzalloc(sizeof(*bank) + num_locks * sizeof(*hwlock), GFP_KERNEL);
+	bank = kzalloc(struct_size(bank, lock, num_locks), GFP_KERNEL);
 	if (!bank) {
 		ret = -ENOMEM;
 		goto iounmap_base;

drivers/infiniband/core/cache.c

···
 			goto err;
 	}
 
-	pkey_cache = kmalloc(sizeof *pkey_cache + tprops->pkey_tbl_len *
-			     sizeof *pkey_cache->table, GFP_KERNEL);
+	pkey_cache = kmalloc(struct_size(pkey_cache, table,
+					 tprops->pkey_tbl_len),
+			     GFP_KERNEL);
 	if (!pkey_cache)
 		goto err;
 

drivers/infiniband/core/cm.c

···
 	int count = 0;
 	u8 i;
 
-	cm_dev = kzalloc(sizeof(*cm_dev) + sizeof(*port) *
-			 ib_device->phys_port_cnt, GFP_KERNEL);
+	cm_dev = kzalloc(struct_size(cm_dev, port, ib_device->phys_port_cnt),
+			 GFP_KERNEL);
 	if (!cm_dev)
 		return;
 

drivers/infiniband/core/multicast.c

···
 	int i;
 	int count = 0;
 
-	dev = kmalloc(sizeof *dev + device->phys_port_cnt * sizeof *port,
+	dev = kmalloc(struct_size(dev, port, device->phys_port_cnt),
 		      GFP_KERNEL);
 	if (!dev)
 		return;

drivers/infiniband/core/uverbs_cmd.c

···
 	struct ib_uflow_resources *resources;
 
 	resources =
-		kmalloc(sizeof(*resources) +
-			num_specs * sizeof(*resources->collection), GFP_KERNEL);
+		kmalloc(struct_size(resources, collection, num_specs),
+			GFP_KERNEL);
 
 	if (!resources)
 		return NULL;

drivers/infiniband/core/uverbs_ioctl_merge.c

···
 	if (max_attr_buckets >= 0)
 		num_attr_buckets = max_attr_buckets + 1;
 
-	method = kzalloc(sizeof(*method) +
-			 num_attr_buckets * sizeof(*method->attr_buckets),
+	method = kzalloc(struct_size(method, attr_buckets, num_attr_buckets),
 			 GFP_KERNEL);
 	if (!method)
 		return ERR_PTR(-ENOMEM);
···
 	if (max_method_buckets >= 0)
 		num_method_buckets = max_method_buckets + 1;
 
-	object = kzalloc(sizeof(*object) +
-			 num_method_buckets *
-			 sizeof(*object->method_buckets), GFP_KERNEL);
+	object = kzalloc(struct_size(object, method_buckets,
+				     num_method_buckets),
+			 GFP_KERNEL);
 	if (!object)
 		return ERR_PTR(-ENOMEM);
 
···
 		if (methods_max_bucket < 0)
 			continue;
 
-		hash = kzalloc(sizeof(*hash) +
-			       sizeof(*hash->methods) * (methods_max_bucket + 1),
+		hash = kzalloc(struct_size(hash, methods,
+					   methods_max_bucket + 1),
 			       GFP_KERNEL);
 		if (!hash) {
 			res = -ENOMEM;
···
 	if (max_object_buckets >= 0)
 		num_objects_buckets = max_object_buckets + 1;
 
-	root_spec = kzalloc(sizeof(*root_spec) +
-			    num_objects_buckets * sizeof(*root_spec->object_buckets),
+	root_spec = kzalloc(struct_size(root_spec, object_buckets,
+					num_objects_buckets),
 			    GFP_KERNEL);
 	if (!root_spec)
 		return ERR_PTR(-ENOMEM);
···
 		if (objects_max_bucket < 0)
 			continue;
 
-		hash = kzalloc(sizeof(*hash) +
-			       sizeof(*hash->objects) * (objects_max_bucket + 1),
+		hash = kzalloc(struct_size(hash, objects,
+					   objects_max_bucket + 1),
 			       GFP_KERNEL);
 		if (!hash) {
 			res = -ENOMEM;

drivers/infiniband/hw/mthca/mthca_memfree.c

···
 	obj_per_chunk = MTHCA_TABLE_CHUNK_SIZE / obj_size;
 	num_icm = DIV_ROUND_UP(nobj, obj_per_chunk);
 
-	table = kmalloc(sizeof *table + num_icm * sizeof *table->icm, GFP_KERNEL);
+	table = kmalloc(struct_size(table, icm, num_icm), GFP_KERNEL);
 	if (!table)
 		return NULL;
 
···
 		return NULL;
 
 	npages = dev->uar_table.uarc_size / MTHCA_ICM_PAGE_SIZE;
-	db_tab = kmalloc(sizeof *db_tab + npages * sizeof *db_tab->page, GFP_KERNEL);
+	db_tab = kmalloc(struct_size(db_tab, page, npages), GFP_KERNEL);
 	if (!db_tab)
 		return ERR_PTR(-ENOMEM);
 

drivers/infiniband/sw/rdmavt/mr.c

···
 
 	/* Allocate struct plus pointers to first level page tables. */
 	m = (count + RVT_SEGSZ - 1) / RVT_SEGSZ;
-	mr = kzalloc(sizeof(*mr) + m * sizeof(mr->mr.map[0]), GFP_KERNEL);
+	mr = kzalloc(struct_size(mr, mr.map, m), GFP_KERNEL);
 	if (!mr)
 		goto bail;
 
···
 
 	/* Allocate struct plus pointers to first level page tables. */
 	m = (fmr_attr->max_pages + RVT_SEGSZ - 1) / RVT_SEGSZ;
-	fmr = kzalloc(sizeof(*fmr) + m * sizeof(fmr->mr.map[0]), GFP_KERNEL);
+	fmr = kzalloc(struct_size(fmr, mr.map, m), GFP_KERNEL);
 	if (!fmr)
 		goto bail;
 

drivers/input/input-leds.c

···
 	if (!num_leds)
 		return -ENXIO;
 
-	leds = kzalloc(sizeof(*leds) + num_leds * sizeof(*leds->leds),
-		       GFP_KERNEL);
+	leds = kzalloc(struct_size(leds, leds, num_leds), GFP_KERNEL);
 	if (!leds)
 		return -ENOMEM;
 

drivers/input/input-mt.c

···
 	if (mt)
 		return mt->num_slots != num_slots ? -EINVAL : 0;
 
-	mt = kzalloc(sizeof(*mt) + num_slots * sizeof(*mt->slots), GFP_KERNEL);
+	mt = kzalloc(struct_size(mt, slots, num_slots), GFP_KERNEL);
 	if (!mt)
 		goto err_mem;
 

drivers/md/dm-raid.c

···
 		return ERR_PTR(-EINVAL);
 	}
 
-	rs = kzalloc(sizeof(*rs) + raid_devs * sizeof(rs->dev[0]), GFP_KERNEL);
+	rs = kzalloc(struct_size(rs, dev, raid_devs), GFP_KERNEL);
 	if (!rs) {
 		ti->error = "Cannot allocate raid context";
 		return ERR_PTR(-ENOMEM);

drivers/misc/vexpress-syscfg.c

···
 		val = energy_quirk;
 	}
 
-	func = kzalloc(sizeof(*func) + sizeof(*func->template) * num,
-			GFP_KERNEL);
+	func = kzalloc(struct_size(func, template, num), GFP_KERNEL);
 	if (!func)
 		return ERR_PTR(-ENOMEM);
 

drivers/net/ethernet/mellanox/mlx5/core/debugfs.c

···
 	int err;
 	int i;
 
-	d = kzalloc(sizeof(*d) + nfile * sizeof(d->fields[0]), GFP_KERNEL);
+	d = kzalloc(struct_size(d, fields, nfile), GFP_KERNEL);
 	if (!d)
 		return -ENOMEM;
 

drivers/net/ethernet/mellanox/mlx5/core/fs_core.c

···
 {
 	struct mlx5_flow_handle *handle;
 
-	handle = kzalloc(sizeof(*handle) + sizeof(handle->rule[0]) *
-			  num_rules, GFP_KERNEL);
+	handle = kzalloc(struct_size(handle, rule, num_rules), GFP_KERNEL);
 	if (!handle)
 		return NULL;
 

drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c

···
 
 			mvmsta = iwl_mvm_sta_from_mac80211(sta);
 			WARN_ON(rcu_access_pointer(mvmsta->ptk_pn[keyidx]));
-			ptk_pn = kzalloc(sizeof(*ptk_pn) +
-					 mvm->trans->num_rx_queues *
-						sizeof(ptk_pn->q[0]),
+			ptk_pn = kzalloc(struct_size(ptk_pn, q,
+						     mvm->trans->num_rx_queues),
 					 GFP_KERNEL);
 			if (!ptk_pn) {
 				ret = -ENOMEM;

drivers/net/wireless/mediatek/mt76/agg-rx.c

···
 
 	mt76_rx_aggr_stop(dev, wcid, tidno);
 
-	tid = kzalloc(sizeof(*tid) + size * sizeof(tid->reorder_buf[0]),
-		      GFP_KERNEL);
+	tid = kzalloc(struct_size(tid, reorder_buf, size), GFP_KERNEL);
 	if (!tid)
 		return -ENOMEM;
 

drivers/reset/core.c

···
 	if (num < 0)
 		return optional ? NULL : ERR_PTR(num);
 
-	resets = kzalloc(sizeof(*resets) + sizeof(resets->rstc[0]) * num,
-			 GFP_KERNEL);
+	resets = kzalloc(struct_size(resets, rstc, num), GFP_KERNEL);
 	if (!resets)
 		return ERR_PTR(-ENOMEM);
 

drivers/s390/cio/ccwgroup.c

···
 	if (num_devices < 1)
 		return -EINVAL;
 
-	gdev = kzalloc(sizeof(*gdev) + num_devices * sizeof(gdev->cdev[0]),
-		       GFP_KERNEL);
+	gdev = kzalloc(struct_size(gdev, cdev, num_devices), GFP_KERNEL);
 	if (!gdev)
 		return -ENOMEM;
 

drivers/staging/greybus/module.c

···
 	struct gb_module *module;
 	int i;
 
-	module = kzalloc(sizeof(*module) + num_interfaces * sizeof(intf),
-				GFP_KERNEL);
+	module = kzalloc(struct_size(module, interfaces, num_interfaces),
+			 GFP_KERNEL);
 	if (!module)
 		return NULL;
 

drivers/usb/gadget/function/f_midi.c

···
 	}
 
 	/* allocate and initialize one new instance */
-	midi = kzalloc(
-		sizeof(*midi) + opts->in_ports * sizeof(*midi->in_ports_array),
-		GFP_KERNEL);
+	midi = kzalloc(struct_size(midi, in_ports_array, opts->in_ports),
+		       GFP_KERNEL);
 	if (!midi) {
 		status = -ENOMEM;
 		goto setup_fail;

drivers/zorro/zorro.c

···
 	int error;
 
 	/* Initialize the Zorro bus */
-	bus = kzalloc(sizeof(*bus) +
-		      zorro_num_autocon * sizeof(bus->devices[0]),
+	bus = kzalloc(struct_size(bus, devices, zorro_num_autocon),
 		      GFP_KERNEL);
 	if (!bus)
 		return -ENOMEM;

fs/afs/addr_list.c

···
 
 	_enter("%u,%u,%u", nr, service, port);
 
-	alist = kzalloc(sizeof(*alist) + sizeof(alist->addrs[0]) * nr,
-			GFP_KERNEL);
+	alist = kzalloc(struct_size(alist, addrs, nr), GFP_KERNEL);
 	if (!alist)
 		return NULL;
 

kernel/cgroup/cgroup.c

···
 	int ret;
 
 	/* allocate the cgroup and its ID, 0 is reserved for the root */
-	cgrp = kzalloc(sizeof(*cgrp) +
-		       sizeof(cgrp->ancestor_ids[0]) * (level + 1), GFP_KERNEL);
+	cgrp = kzalloc(struct_size(cgrp, ancestor_ids, (level + 1)),
+		       GFP_KERNEL);
 	if (!cgrp)
 		return ERR_PTR(-ENOMEM);
 

kernel/module.c

···
 	if (notes == 0)
 		return;
 
-	notes_attrs = kzalloc(sizeof(*notes_attrs)
-			      + notes * sizeof(notes_attrs->attrs[0]),
+	notes_attrs = kzalloc(struct_size(notes_attrs, attrs, notes),
 			      GFP_KERNEL);
 	if (notes_attrs == NULL)
 		return;

kernel/workqueue.c

···
 
 	lockdep_assert_held(&wq_pool_mutex);
 
-	ctx = kzalloc(sizeof(*ctx) + nr_node_ids * sizeof(ctx->pwq_tbl[0]),
-		      GFP_KERNEL);
+	ctx = kzalloc(struct_size(ctx, pwq_tbl, nr_node_ids), GFP_KERNEL);
 
 	new_attrs = alloc_workqueue_attrs(GFP_KERNEL);
 	tmp_attrs = alloc_workqueue_attrs(GFP_KERNEL);

net/ceph/mon_client.c

···
 
 	if (num_mon > CEPH_MAX_MON)
 		goto bad;
-	m = kmalloc(sizeof(*m) + sizeof(m->mon_inst[0])*num_mon, GFP_NOFS);
+	m = kmalloc(struct_size(m, mon_inst, num_mon), GFP_NOFS);
 	if (m == NULL)
 		return ERR_PTR(-ENOMEM);
 	m->fsid = fsid;
···
 	int i;
 
 	/* build initial monmap */
-	monc->monmap = kzalloc(sizeof(*monc->monmap) +
-			       num_mon*sizeof(monc->monmap->mon_inst[0]),
+	monc->monmap = kzalloc(struct_size(monc->monmap, mon_inst, num_mon),
 			       GFP_KERNEL);
 	if (!monc->monmap)
 		return -ENOMEM;

net/ceph/osd_client.c

···
 		req = kmem_cache_alloc(ceph_osd_request_cache, gfp_flags);
 	} else {
 		BUG_ON(num_ops > CEPH_OSD_MAX_OPS);
-		req = kmalloc(sizeof(*req) + num_ops * sizeof(req->r_ops[0]),
-			      gfp_flags);
+		req = kmalloc(struct_size(req, r_ops, num_ops), gfp_flags);
 	}
 	if (unlikely(!req))
 		return NULL;

net/netfilter/xt_recent.c

···
 	}
 
 	nstamps_max += 1;
-	e = kmalloc(sizeof(*e) + sizeof(e->stamps[0]) * nstamps_max,
-		    GFP_ATOMIC);
+	e = kmalloc(struct_size(e, stamps, nstamps_max), GFP_ATOMIC);
 	if (e == NULL)
 		return NULL;
 	memcpy(&e->addr, addr, sizeof(e->addr));

net/sctp/endpointola.c

···
 		 * variables.  There are arrays that we encode directly
 		 * into parameters to make the rest of the operations easier.
 		 */
-		auth_hmacs = kzalloc(sizeof(*auth_hmacs) +
-				     sizeof(__u16) * SCTP_AUTH_NUM_HMACS, gfp);
+		auth_hmacs = kzalloc(struct_size(auth_hmacs, hmac_ids,
+						 SCTP_AUTH_NUM_HMACS), gfp);
 		if (!auth_hmacs)
 			goto nomem;
 

sound/core/vmaster.c

···
 	struct link_master *master_link = snd_kcontrol_chip(master);
 	struct link_slave *srec;
 
-	srec = kzalloc(sizeof(*srec) +
-		       slave->count * sizeof(*slave->vd), GFP_KERNEL);
+	srec = kzalloc(struct_size(srec, slave.vd, slave->count),
+		       GFP_KERNEL);
 	if (!srec)
 		return -ENOMEM;
 	srec->kctl = slave;

sound/soc/soc-dapm.c

···
 	list_for_each(it, widgets)
 		size++;
 
-	*list = kzalloc(sizeof(**list) + size * sizeof(*w), GFP_KERNEL);
+	*list = kzalloc(struct_size(*list, widgets, size), GFP_KERNEL);
 	if (*list == NULL)
 		return -ENOMEM;