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 <keescook@chromium.org>
Signed-off-by: Adam W. Willis <return.of.octobot@gmail.com>
Signed-off-by: UtsavBalar1231 <utsavbalar1231@gmail.com>

drivers/clk/berlin/bg2.c

@@ -509,8 +509,7 @@ static void __init berlin2_clock_setup(struct device_node *np)
 	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

@@ -295,8 +295,7 @@ static void __init berlin2q_clock_setup(struct device_node *np)
 	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

@@ -273,8 +273,7 @@ static void __init asm9260_acc_init(struct device_node *np)
 	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-efm32gg.c

@@ -25,8 +25,8 @@ static void __init efm32gg_cmu_init(struct device_node *np)
 	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

@@ -399,9 +399,8 @@ static void __init gemini_cc_init(struct device_node *np)
 	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

@@ -1214,9 +1214,8 @@ static void __init stm32h7_rcc_init(struct device_node *np)
 	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/cpufreq/cpufreq_times.c

@@ -489,8 +489,7 @@ void cpufreq_times_create_policy(struct cpufreq_policy *policy)
 	cpufreq_for_each_valid_entry(pos, table)
 		count++;
 
-	tmp =  kzalloc(sizeof(*freqs) + sizeof(freqs->freq_table[0]) * count,
-		       GFP_KERNEL);
+	tmp =  kzalloc(struct_size(freqs, freq_table, count), GFP_KERNEL);
 	if (!tmp)
 		return;
 

drivers/dma/edma.c

@@ -1073,8 +1073,7 @@ static struct dma_async_tx_descriptor *edma_prep_slave_sg(
 		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;
 
@@ -1191,8 +1190,7 @@ static struct dma_async_tx_descriptor *edma_prep_dma_memcpy(
 			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;
 
@@ -1314,8 +1312,7 @@ static struct dma_async_tx_descriptor *edma_prep_dma_cyclic(
 		}
 	}
 
-	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

@@ -309,7 +309,7 @@ static struct dma_async_tx_descriptor *moxart_prep_slave_sg(
 		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

@@ -917,7 +917,7 @@ static struct dma_async_tx_descriptor *omap_dma_prep_slave_sg(
 	}
 
 	/* 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

@@ -557,7 +557,7 @@ static struct dma_async_tx_descriptor *sa11x0_dma_prep_slave_sg(
 		}
 	}
 
-	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;
@@ -627,7 +627,7 @@ static struct dma_async_tx_descriptor *sa11x0_dma_prep_dma_cyclic(
 	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

@@ -269,7 +269,7 @@ static int usb_dmac_desc_alloc(struct usb_dmac_chan *chan, unsigned int sg_len,
 	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

@@ -112,8 +112,7 @@ static struct fw_node *fw_node_create(u32 sid, int port_count, int color)
 {
 	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

@@ -3579,8 +3579,7 @@ struct gpio_descs *__must_check gpiod_get_array(struct device *dev,
 	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

@@ -779,8 +779,8 @@ nvkm_perfdom_new(struct nvkm_pm *pm, const char *name, u32 mask,
 
 		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/infiniband/core/cache.c

@@ -1074,16 +1074,16 @@ static void ib_cache_update(struct ib_device *device,
 		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;
 
 	pkey_cache->table_len = tprops->pkey_tbl_len;
 
 	if (!use_roce_gid_table) {
-		gid_cache = kmalloc(sizeof(*gid_cache) + tprops->gid_tbl_len *
-			    sizeof(*gid_cache->table), GFP_KERNEL);
+		gid_cache = kmalloc(struct_size(gid_cache, table, tprops->gid_tbl_len),
+				    GFP_KERNEL);
 		if (!gid_cache)
 			goto err;
 

drivers/infiniband/core/uverbs_ioctl_merge.c

@@ -297,8 +297,7 @@ static struct uverbs_method_spec *build_method_with_attrs(const struct uverbs_me
 	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);
@@ -446,9 +445,8 @@ static struct uverbs_object_spec *build_object_with_methods(const struct uverbs_
 	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);
 
@@ -469,8 +467,7 @@ static struct uverbs_object_spec *build_object_with_methods(const struct uverbs_
 		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;
@@ -579,8 +576,7 @@ struct uverbs_root_spec *uverbs_alloc_spec_tree(unsigned int num_trees,
 	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);
@@ -603,8 +599,7 @@ struct uverbs_root_spec *uverbs_alloc_spec_tree(unsigned int num_trees,
 		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

@@ -367,7 +367,7 @@ struct mthca_icm_table *mthca_alloc_icm_table(struct mthca_dev *dev,
 	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;
 
@@ -529,7 +529,7 @@ struct mthca_user_db_table *mthca_init_user_db_tab(struct mthca_dev *dev)
 		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/input/input-leds.c

@@ -98,8 +98,7 @@ static int input_leds_connect(struct input_handler *handler,
 	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

@@ -49,7 +49,7 @@ int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots,
 	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/input/misc/gpio_input.c

@@ -287,8 +287,8 @@ int gpio_event_input_func(struct gpio_event_input_devs *input_devs,
 		if (ktime_to_ns(di->poll_time) <= 0)
 			di->poll_time = ktime_set(0, 20 * NSEC_PER_MSEC);
 
-		*data = ds = kzalloc(sizeof(*ds) + sizeof(ds->key_state[0]) *
-					di->keymap_size, GFP_KERNEL);
+		*data = ds = kzalloc(struct_size(ds, key_state, di->keymap_size),
+				     GFP_KERNEL);
 		if (ds == NULL) {
 			ret = -ENOMEM;
 			pr_err("gpio_event_input_func: "

drivers/input/misc/gpio_matrix.c

@@ -327,8 +327,8 @@ int gpio_event_matrix_func(struct gpio_event_input_devs *input_devs,
 		}
 		key_count = mi->ninputs * mi->noutputs;
 
-		*data = kp = kzalloc(sizeof(*kp) + sizeof(kp->keys_pressed[0]) *
-				     BITS_TO_LONGS(key_count), GFP_KERNEL);
+		*data = kp = kzalloc(struct_size(kp, keys_pressed, BITS_TO_LONGS(key_count)),
+				     GFP_KERNEL);
 		if (kp == NULL) {
 			err = -ENOMEM;
 			pr_err("gpiomatrix: Failed to allocate private data\n");

drivers/md/dm-raid.c

@@ -740,7 +740,7 @@ static struct raid_set *raid_set_alloc(struct dm_target *ti, struct raid_type *r
 		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

@@ -182,8 +182,7 @@ static struct regmap *vexpress_syscfg_regmap_init(struct device *dev,
 		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

@@ -494,7 +494,7 @@ static int add_res_tree(struct mlx5_core_dev *dev, enum dbg_rsc_type type,
 	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

@@ -1053,8 +1053,7 @@ static struct mlx5_flow_handle *alloc_handle(int num_rules)
 {
 	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

@@ -3020,9 +3020,7 @@ static int iwl_mvm_mac_set_key(struct ieee80211_hw *hw,
 
 			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/intel/iwlwifi/mvm/sta.c

@@ -2223,9 +2223,7 @@ int iwl_mvm_sta_rx_agg(struct iwl_mvm *mvm, struct ieee80211_sta *sta,
 		 * Allocate here so if allocation fails we can bail out early
 		 * before starting the BA session in the firmware
 		 */
-		baid_data = kzalloc(sizeof(*baid_data) +
-				    mvm->trans->num_rx_queues *
-				    sizeof(baid_data->reorder_buf[0]),
+		baid_data = kzalloc(struct_size(baid_data, reorder_buf, mvm->trans->num_rx_queues),
 				    GFP_KERNEL);
 		if (!baid_data)
 			return -ENOMEM;

drivers/reset/core.c

@@ -638,8 +638,7 @@ of_reset_control_array_get(struct device_node *np, bool shared, bool optional)
 	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

@@ -322,8 +322,7 @@ int ccwgroup_create_dev(struct device *parent, struct ccwgroup_driver *gdrv,
 	struct ccw_dev_id dev_id;
 	int rc, i;
 
-	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/usb/gadget/function/f_midi.c

@@ -1353,9 +1353,8 @@ static struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
 	}
 
 	/* 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

@@ -136,8 +136,7 @@ static int __init amiga_zorro_probe(struct platform_device *pdev)
 	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;

kernel/cgroup/cgroup.c

@@ -4894,8 +4894,8 @@ static struct cgroup *cgroup_create(struct cgroup *parent)
 	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

@@ -1599,8 +1599,7 @@ static void add_notes_attrs(struct module *mod, const struct load_info *info)
 	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

@@ -3713,8 +3713,7 @@ apply_wqattrs_prepare(struct workqueue_struct *wq,
 
 	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

@@ -62,7 +62,7 @@ struct ceph_monmap *ceph_monmap_decode(void *p, void *end)
 
 	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;

net/ceph/osd_client.c

@@ -527,8 +527,7 @@ struct ceph_osd_request *ceph_osdc_alloc_request(struct ceph_osd_client *osdc,
 		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

@@ -184,8 +184,7 @@ recent_entry_init(struct recent_table *t, const union nf_inet_addr *addr,
 	}
 
 	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));