github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-07-27 09:36:22 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

selftests/bpf: Cover refcount acquire node offsets

Browse Source 
Add regression coverage for bpf_refcount_acquire() on graph-node-derived
pointers.

The rejected case passes a popped list node pointer directly to
bpf_refcount_acquire(), which must fail because the pointer carries a
non-zero fixed offset.

Signed-off-by: Yiyang Chen <chenyy23@mails.tsinghua.edu.cn>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/bf2a2033ced272106292de4465b8ef3fb991c912.1782192383.git.chenyy23@mails.tsinghua.edu.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Yiyang Chen 2026-06-23 06:11:10 +00:00 committed by Alexei Starovoitov
parent 931a577fc7
commit 0371fb57a0
1 changed files with 34 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
tools/testing/selftests/bpf/progs/refcounted_kptr_fail.c
View File

@ -13,12 +13,20 @@ struct node_acquire {
struct bpf_refcount refcount;
};
struct node_refcounted {
long key;
struct bpf_list_node list;
struct bpf_refcount refcount;
};
extern void bpf_rcu_read_lock(void) __ksym;
extern void bpf_rcu_read_unlock(void) __ksym;
#define private(name) SEC(".data." #name) __hidden __attribute__((aligned(8)))
private(A) struct bpf_spin_lock glock;
private(A) struct bpf_rb_root groot __contains(node_acquire, node);
private(B) struct bpf_spin_lock lock;
private(B) struct bpf_list_head head __contains(node_refcounted, list);
static bool less(struct bpf_rb_node *a, const struct bpf_rb_node *b)
{
@ -93,6 +101,32 @@ long rbtree_refcounted_node_ref_escapes_owning_input(void *ctx)
return 0;
}
SEC("?tc")
__failure __msg("dereference of modified ptr_ ptr R1")
long refcount_acquire_list_node_offset(void *ctx)
{
struct node_refcounted *node, *base, *ref;
struct bpf_list_node *list_node;
node = bpf_obj_new(typeof(*node));
if (!node)
return 1;
bpf_spin_lock(&lock);
bpf_list_push_front(&head, &node->list);
list_node = bpf_list_pop_front(&head);
bpf_spin_unlock(&lock);
if (!list_node)
return 2;
base = container_of(list_node, struct node_refcounted, list);
ref = bpf_refcount_acquire(list_node);
if (ref)
bpf_obj_drop(ref);
bpf_obj_drop(base);
return 0;
}
SEC("?fentry.s/" SYS_PREFIX "sys_getpgid")
__failure __msg("function calls are not allowed while holding a lock")
int BPF_PROG(rbtree_fail_sleepable_lock_across_rcu,