Merge branch 'bpf-obj-name-misc'

Martin KaFai Lau says:

====================
bpf: Misc improvements and a new usage on bpf obj name

The first two patches make improvements on the bpf obj name.

The last patch adds the prog name to kallsyms.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/bpf.h

@@ -56,7 +56,7 @@ struct bpf_map {
 	struct work_struct work;
 	atomic_t usercnt;
 	struct bpf_map *inner_map_meta;
-	u8 name[BPF_OBJ_NAME_LEN];
+	char name[BPF_OBJ_NAME_LEN];
 };
 
 /* function argument constraints */
@@ -189,7 +189,7 @@ struct bpf_prog_aux {
 	struct bpf_prog *prog;
 	struct user_struct *user;
 	u64 load_time; /* ns since boottime */
-	u8 name[BPF_OBJ_NAME_LEN];
+	char name[BPF_OBJ_NAME_LEN];
 	union {
 		struct work_struct work;
 		struct rcu_head	rcu;

include/uapi/linux/bpf.h

@@ -230,7 +230,7 @@ union bpf_attr {
 		__u32	numa_node;	/* numa node (effective only if
 					 * BPF_F_NUMA_NODE is set).
 					 */
-		__u8	map_name[BPF_OBJ_NAME_LEN];
+		char	map_name[BPF_OBJ_NAME_LEN];
 	};
 
 	struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
@@ -253,7 +253,7 @@ union bpf_attr {
 		__aligned_u64	log_buf;	/* user supplied buffer */
 		__u32		kern_version;	/* checked when prog_type=kprobe */
 		__u32		prog_flags;
-		__u8		prog_name[BPF_OBJ_NAME_LEN];
+		char		prog_name[BPF_OBJ_NAME_LEN];
 	};
 
 	struct { /* anonymous struct used by BPF_OBJ_* commands */
@@ -888,7 +888,7 @@ struct bpf_prog_info {
 	__u32 created_by_uid;
 	__u32 nr_map_ids;
 	__aligned_u64 map_ids;
-	__u8  name[BPF_OBJ_NAME_LEN];
+	char name[BPF_OBJ_NAME_LEN];
 } __attribute__((aligned(8)));
 
 struct bpf_map_info {
@@ -898,7 +898,7 @@ struct bpf_map_info {
 	__u32 value_size;
 	__u32 max_entries;
 	__u32 map_flags;
-	__u8  name[BPF_OBJ_NAME_LEN];
+	char  name[BPF_OBJ_NAME_LEN];
 } __attribute__((aligned(8)));
 
 /* User bpf_sock_ops struct to access socket values and specify request ops

kernel/bpf/core.c

@@ -309,12 +309,25 @@ bpf_get_prog_addr_region(const struct bpf_prog *prog,
 
 static void bpf_get_prog_name(const struct bpf_prog *prog, char *sym)
 {
+	const char *end = sym + KSYM_NAME_LEN;
+
 	BUILD_BUG_ON(sizeof("bpf_prog_") +
-		     sizeof(prog->tag) * 2 + 1 > KSYM_NAME_LEN);
+		     sizeof(prog->tag) * 2 +
+		     /* name has been null terminated.
+		      * We should need +1 for the '_' preceding
+		      * the name.  However, the null character
+		      * is double counted between the name and the
+		      * sizeof("bpf_prog_") above, so we omit
+		      * the +1 here.
+		      */
+		     sizeof(prog->aux->name) > KSYM_NAME_LEN);
 
 	sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_");
 	sym  = bin2hex(sym, prog->tag, sizeof(prog->tag));
-	*sym = 0;
+	if (prog->aux->name[0])
+		snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name);
+	else
+		*sym = 0;
 }
 
 static __always_inline unsigned long

kernel/bpf/syscall.c

@@ -322,6 +322,8 @@ static int bpf_obj_name_cpy(char *dst, const char *src)
 {
 	const char *end = src + BPF_OBJ_NAME_LEN;
 
+	memset(dst, 0, BPF_OBJ_NAME_LEN);
+
 	/* Copy all isalnum() and '_' char */
 	while (src < end && *src) {
 		if (!isalnum(*src) && *src != '_')
@@ -333,9 +335,6 @@ static int bpf_obj_name_cpy(char *dst, const char *src)
 	if (src == end)
 		return -EINVAL;
 
-	/* '\0' terminates dst */
-	*dst = 0;
-
 	return 0;
 }
 

tools/include/uapi/linux/bpf.h

@@ -230,7 +230,7 @@ union bpf_attr {
 		__u32	numa_node;	/* numa node (effective only if
 					 * BPF_F_NUMA_NODE is set).
 					 */
-		__u8	map_name[BPF_OBJ_NAME_LEN];
+		char	map_name[BPF_OBJ_NAME_LEN];
 	};
 
 	struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
@@ -253,7 +253,7 @@ union bpf_attr {
 		__aligned_u64	log_buf;	/* user supplied buffer */
 		__u32		kern_version;	/* checked when prog_type=kprobe */
 		__u32		prog_flags;
-		__u8		prog_name[BPF_OBJ_NAME_LEN];
+		char		prog_name[BPF_OBJ_NAME_LEN];
 	};
 
 	struct { /* anonymous struct used by BPF_OBJ_* commands */
@@ -871,7 +871,7 @@ struct bpf_prog_info {
 	__u32 created_by_uid;
 	__u32 nr_map_ids;
 	__aligned_u64 map_ids;
-	__u8  name[BPF_OBJ_NAME_LEN];
+	char  name[BPF_OBJ_NAME_LEN];
 } __attribute__((aligned(8)));
 
 struct bpf_map_info {
@@ -881,7 +881,7 @@ struct bpf_map_info {
 	__u32 value_size;
 	__u32 max_entries;
 	__u32 map_flags;
-	__u8  name[BPF_OBJ_NAME_LEN];
+	char  name[BPF_OBJ_NAME_LEN];
 } __attribute__((aligned(8)));
 
 /* User bpf_sock_ops struct to access socket values and specify request ops