Commit 41948afc authored by Thorsten Blum's avatar Thorsten Blum Committed by Andrii Nakryiko
Browse files

bpf: Replace offsetof() with struct_size() 



Compared to offsetof(), struct_size() provides additional compile-time
checks for structs with flexible arrays (e.g., __must_be_array()).

No functional changes intended.

Signed-off-by: default avatarThorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250503151513.343931-2-thorsten.blum@linux.dev
parent 41d4ce6d

kernel/bpf/btf.c

+9 −10
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ 
#include <linux/bsearch.h>

#include <linux/kobject.h>

#include <linux/sysfs.h>

#include <linux/overflow.h>



#include <net/netfilter/nf_bpf_link.h>
@@ -3957,7 +3958,7 @@ struct btf_record *btf_parse_fields(const struct btf *btf, const struct btf_type 
	/* This needs to be kzalloc to zero out padding and unused fields, see

	 * comment in btf_record_equal.

	 */

	rec = kzalloc(offsetof(struct btf_record, fields[cnt]), GFP_KERNEL | __GFP_NOWARN);

	rec = kzalloc(struct_size(rec, fields, cnt), GFP_KERNEL | __GFP_NOWARN);

	if (!rec)

		return ERR_PTR(-ENOMEM);
@@ -5583,7 +5584,7 @@ btf_parse_struct_metas(struct bpf_verifier_log *log, struct btf *btf) 
		if (id < 0)

			continue;



		new_aof = krealloc(aof, offsetof(struct btf_id_set, ids[aof->cnt + 1]),

		new_aof = krealloc(aof, struct_size(new_aof, ids, aof->cnt + 1),

				   GFP_KERNEL | __GFP_NOWARN);

		if (!new_aof) {

			ret = -ENOMEM;
@@ -5610,7 +5611,7 @@ btf_parse_struct_metas(struct bpf_verifier_log *log, struct btf *btf) 
		if (ret != BTF_FIELD_FOUND)

			continue;



		new_aof = krealloc(aof, offsetof(struct btf_id_set, ids[aof->cnt + 1]),

		new_aof = krealloc(aof, struct_size(new_aof, ids, aof->cnt + 1),

				   GFP_KERNEL | __GFP_NOWARN);

		if (!new_aof) {

			ret = -ENOMEM;
@@ -5647,7 +5648,7 @@ btf_parse_struct_metas(struct bpf_verifier_log *log, struct btf *btf) 
		continue;

	parse:

		tab_cnt = tab ? tab->cnt : 0;

		new_tab = krealloc(tab, offsetof(struct btf_struct_metas, types[tab_cnt + 1]),

		new_tab = krealloc(tab, struct_size(new_tab, types, tab_cnt + 1),

				   GFP_KERNEL | __GFP_NOWARN);

		if (!new_tab) {

			ret = -ENOMEM;
@@ -8559,7 +8560,7 @@ static int btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook, 


	/* Grow set */

	set = krealloc(tab->sets[hook],

		       offsetof(struct btf_id_set8, pairs[set_cnt + add_set->cnt]),

		       struct_size(set, pairs, set_cnt + add_set->cnt),

		       GFP_KERNEL | __GFP_NOWARN);

	if (!set) {

		ret = -ENOMEM;
@@ -8845,7 +8846,7 @@ int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors, u32 add_c 
	}



	tab = krealloc(btf->dtor_kfunc_tab,

		       offsetof(struct btf_id_dtor_kfunc_tab, dtors[tab_cnt + add_cnt]),

		       struct_size(tab, dtors, tab_cnt + add_cnt),

		       GFP_KERNEL | __GFP_NOWARN);

	if (!tab) {

		ret = -ENOMEM;
@@ -9403,8 +9404,7 @@ btf_add_struct_ops(struct btf *btf, struct bpf_struct_ops *st_ops, 


	tab = btf->struct_ops_tab;

	if (!tab) {

		tab = kzalloc(offsetof(struct btf_struct_ops_tab, ops[4]),

			      GFP_KERNEL);

		tab = kzalloc(struct_size(tab, ops, 4), GFP_KERNEL);

		if (!tab)

			return -ENOMEM;

		tab->capacity = 4;
@@ -9417,8 +9417,7 @@ btf_add_struct_ops(struct btf *btf, struct bpf_struct_ops *st_ops, 


	if (tab->cnt == tab->capacity) {

		new_tab = krealloc(tab,

				   offsetof(struct btf_struct_ops_tab,

					    ops[tab->capacity * 2]),

				   struct_size(tab, ops, tab->capacity * 2),

				   GFP_KERNEL);

		if (!new_tab)

			return -ENOMEM;