* [PATCH bpf-next v12 1/8] bpf: Extend BPF syscall with common attributes support
2026-04-20 14:17 [PATCH bpf-next v12 0/8] bpf: Extend BPF syscall with common attributes support Leon Hwang
@ 2026-04-20 14:17 ` Leon Hwang
2026-04-20 14:17 ` [PATCH bpf-next v12 2/8] libbpf: Add support for extended BPF syscall Leon Hwang
` (6 subsequent siblings)
7 siblings, 0 replies; 11+ messages in thread
From: Leon Hwang @ 2026-04-20 14:17 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Daniel Borkmann, John Fastabend,
Andrii Nakryiko, Martin KaFai Lau, Eduard Zingerman, Song Liu,
Yonghong Song, KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa,
Shuah Khan, Christian Brauner, Seth Forshee, Yuichiro Tsuji,
Andrey Albershteyn, Leon Hwang, Willem de Bruijn, Jason Xing,
Tao Chen, Mykyta Yatsenko, Kumar Kartikeya Dwivedi,
Anton Protopopov, Amery Hung, Rong Tao, linux-kernel, linux-api,
linux-kselftest, kernel-patches-bot
Add generic BPF syscall support for passing common attributes.
The initial set of common attributes includes:
1. 'log_buf': User-provided buffer for storing logs.
2. 'log_size': Size of the log buffer.
3. 'log_level': Log verbosity level.
4. 'log_true_size': Actual log size reported by kernel.
The common-attribute pointer and its size are passed as the 4th and 5th
syscall arguments. A new command bit, 'BPF_COMMON_ATTRS' ('1 << 16'),
indicates that common attributes are supplied.
This commit adds syscall and uapi plumbing. Command-specific handling is
added in follow-up patches.
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
---
include/linux/syscalls.h | 3 ++-
include/uapi/linux/bpf.h | 8 ++++++++
kernel/bpf/syscall.c | 25 +++++++++++++++++++++----
tools/include/uapi/linux/bpf.h | 8 ++++++++
4 files changed, 39 insertions(+), 5 deletions(-)
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 02bd6ddb6278..f4848c64872f 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -936,7 +936,8 @@ asmlinkage long sys_seccomp(unsigned int op, unsigned int flags,
asmlinkage long sys_getrandom(char __user *buf, size_t count,
unsigned int flags);
asmlinkage long sys_memfd_create(const char __user *uname_ptr, unsigned int flags);
-asmlinkage long sys_bpf(int cmd, union bpf_attr __user *attr, unsigned int size);
+asmlinkage long sys_bpf(int cmd, union bpf_attr __user *attr, unsigned int size,
+ struct bpf_common_attr __user *attr_common, unsigned int size_common);
asmlinkage long sys_execveat(int dfd, const char __user *filename,
const char __user *const __user *argv,
const char __user *const __user *envp, int flags);
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 552bc5d9afbd..49eeb18ad050 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -994,6 +994,7 @@ enum bpf_cmd {
BPF_PROG_STREAM_READ_BY_FD,
BPF_PROG_ASSOC_STRUCT_OPS,
__MAX_BPF_CMD,
+ BPF_COMMON_ATTRS = 1 << 16, /* Indicate carrying syscall common attrs. */
};
enum bpf_map_type {
@@ -1500,6 +1501,13 @@ struct bpf_stack_build_id {
};
};
+struct bpf_common_attr {
+ __u64 log_buf;
+ __u32 log_size;
+ __u32 log_level;
+ __u32 log_true_size;
+};
+
#define BPF_OBJ_NAME_LEN 16U
enum {
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index b73b25c63073..5bf84ea21bf5 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -6210,8 +6210,10 @@ static int prog_assoc_struct_ops(union bpf_attr *attr)
return ret;
}
-static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size)
+static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size,
+ bpfptr_t uattr_common, unsigned int size_common)
{
+ struct bpf_common_attr attr_common;
union bpf_attr attr;
int err;
@@ -6225,6 +6227,20 @@ static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size)
if (copy_from_bpfptr(&attr, uattr, size) != 0)
return -EFAULT;
+ memset(&attr_common, 0, sizeof(attr_common));
+ if (cmd & BPF_COMMON_ATTRS) {
+ err = bpf_check_uarg_tail_zero(uattr_common, sizeof(attr_common), size_common);
+ if (err)
+ return err;
+
+ cmd &= ~BPF_COMMON_ATTRS;
+ size_common = min_t(u32, size_common, sizeof(attr_common));
+ if (copy_from_bpfptr(&attr_common, uattr_common, size_common) != 0)
+ return -EFAULT;
+ } else {
+ size_common = 0;
+ }
+
err = security_bpf(cmd, &attr, size, uattr.is_kernel);
if (err < 0)
return err;
@@ -6360,9 +6376,10 @@ static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size)
return err;
}
-SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size)
+SYSCALL_DEFINE5(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size,
+ struct bpf_common_attr __user *, uattr_common, unsigned int, size_common)
{
- return __sys_bpf(cmd, USER_BPFPTR(uattr), size);
+ return __sys_bpf(cmd, USER_BPFPTR(uattr), size, USER_BPFPTR(uattr_common), size_common);
}
static bool syscall_prog_is_valid_access(int off, int size,
@@ -6392,7 +6409,7 @@ BPF_CALL_3(bpf_sys_bpf, int, cmd, union bpf_attr *, attr, u32, attr_size)
default:
return -EINVAL;
}
- return __sys_bpf(cmd, KERNEL_BPFPTR(attr), attr_size);
+ return __sys_bpf(cmd, KERNEL_BPFPTR(attr), attr_size, KERNEL_BPFPTR(NULL), 0);
}
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 677be9a47347..16ff0968fc21 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -994,6 +994,7 @@ enum bpf_cmd {
BPF_PROG_STREAM_READ_BY_FD,
BPF_PROG_ASSOC_STRUCT_OPS,
__MAX_BPF_CMD,
+ BPF_COMMON_ATTRS = 1 << 16, /* Indicate carrying syscall common attrs. */
};
enum bpf_map_type {
@@ -1500,6 +1501,13 @@ struct bpf_stack_build_id {
};
};
+struct bpf_common_attr {
+ __u64 log_buf;
+ __u32 log_size;
+ __u32 log_level;
+ __u32 log_true_size;
+};
+
#define BPF_OBJ_NAME_LEN 16U
enum {
--
2.53.0
^ permalink raw reply related [flat|nested] 11+ messages in thread* [PATCH bpf-next v12 2/8] libbpf: Add support for extended BPF syscall
2026-04-20 14:17 [PATCH bpf-next v12 0/8] bpf: Extend BPF syscall with common attributes support Leon Hwang
2026-04-20 14:17 ` [PATCH bpf-next v12 1/8] " Leon Hwang
@ 2026-04-20 14:17 ` Leon Hwang
2026-04-20 14:17 ` [PATCH bpf-next v12 3/8] bpf: Refactor reporting log_true_size for prog_load Leon Hwang
` (5 subsequent siblings)
7 siblings, 0 replies; 11+ messages in thread
From: Leon Hwang @ 2026-04-20 14:17 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Daniel Borkmann, John Fastabend,
Andrii Nakryiko, Martin KaFai Lau, Eduard Zingerman, Song Liu,
Yonghong Song, KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa,
Shuah Khan, Christian Brauner, Seth Forshee, Yuichiro Tsuji,
Andrey Albershteyn, Leon Hwang, Willem de Bruijn, Jason Xing,
Tao Chen, Mykyta Yatsenko, Kumar Kartikeya Dwivedi,
Anton Protopopov, Amery Hung, Rong Tao, linux-kernel, linux-api,
linux-kselftest, kernel-patches-bot
To support the extended BPF syscall introduced in the previous commit,
introduce the following internal APIs:
* 'sys_bpf_ext()'
* 'sys_bpf_ext_fd()'
They wrap the raw 'syscall()' interface to support passing extended
attributes.
* 'probe_sys_bpf_ext()'
Check whether current kernel supports the BPF syscall common attributes.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
---
tools/lib/bpf/bpf.c | 36 +++++++++++++++++++++++++++++++++
tools/lib/bpf/features.c | 8 ++++++++
tools/lib/bpf/libbpf_internal.h | 3 +++
3 files changed, 47 insertions(+)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 5846de364209..9d8740761b7a 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -69,6 +69,42 @@ static inline __u64 ptr_to_u64(const void *ptr)
return (__u64) (unsigned long) ptr;
}
+static inline int sys_bpf_ext(enum bpf_cmd cmd, union bpf_attr *attr,
+ unsigned int size,
+ struct bpf_common_attr *attr_common,
+ unsigned int size_common)
+{
+ cmd = attr_common ? (cmd | BPF_COMMON_ATTRS) : (cmd & ~BPF_COMMON_ATTRS);
+ return syscall(__NR_bpf, cmd, attr, size, attr_common, size_common);
+}
+
+static inline int sys_bpf_ext_fd(enum bpf_cmd cmd, union bpf_attr *attr,
+ unsigned int size,
+ struct bpf_common_attr *attr_common,
+ unsigned int size_common)
+{
+ int fd;
+
+ fd = sys_bpf_ext(cmd, attr, size, attr_common, size_common);
+ return ensure_good_fd(fd);
+}
+
+int probe_sys_bpf_ext(void)
+{
+ const size_t attr_sz = offsetofend(union bpf_attr, prog_token_fd);
+ union bpf_attr attr;
+ int fd;
+
+ memset(&attr, 0, attr_sz);
+ fd = syscall(__NR_bpf, BPF_PROG_LOAD | BPF_COMMON_ATTRS, &attr, attr_sz, NULL,
+ sizeof(struct bpf_common_attr));
+ if (fd >= 0) {
+ close(fd);
+ return -EINVAL;
+ }
+ return errno == EFAULT ? 1 : 0;
+}
+
static inline int sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr,
unsigned int size)
{
diff --git a/tools/lib/bpf/features.c b/tools/lib/bpf/features.c
index 4f19a0d79b0c..b7e388f99d0b 100644
--- a/tools/lib/bpf/features.c
+++ b/tools/lib/bpf/features.c
@@ -615,6 +615,11 @@ static int probe_kern_btf_layout(int token_fd)
(char *)layout, token_fd));
}
+static int probe_bpf_syscall_common_attrs(int token_fd)
+{
+ return probe_sys_bpf_ext();
+}
+
typedef int (*feature_probe_fn)(int /* token_fd */);
static struct kern_feature_cache feature_cache;
@@ -699,6 +704,9 @@ static struct kern_feature_desc {
[FEAT_BTF_LAYOUT] = {
"kernel supports BTF layout", probe_kern_btf_layout,
},
+ [FEAT_BPF_SYSCALL_COMMON_ATTRS] = {
+ "BPF syscall common attributes support", probe_bpf_syscall_common_attrs,
+ },
};
bool feat_supported(struct kern_feature_cache *cache, enum kern_feature_id feat_id)
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
index cabdaef79098..21ccdf4d9284 100644
--- a/tools/lib/bpf/libbpf_internal.h
+++ b/tools/lib/bpf/libbpf_internal.h
@@ -398,6 +398,8 @@ enum kern_feature_id {
FEAT_UPROBE_SYSCALL,
/* Kernel supports BTF layout information */
FEAT_BTF_LAYOUT,
+ /* Kernel supports BPF syscall common attributes */
+ FEAT_BPF_SYSCALL_COMMON_ATTRS,
__FEAT_CNT,
};
@@ -767,4 +769,5 @@ int probe_fd(int fd);
#define SHA256_DWORD_SIZE SHA256_DIGEST_LENGTH / sizeof(__u64)
void libbpf_sha256(const void *data, size_t len, __u8 out[SHA256_DIGEST_LENGTH]);
+int probe_sys_bpf_ext(void);
#endif /* __LIBBPF_LIBBPF_INTERNAL_H */
--
2.53.0
^ permalink raw reply related [flat|nested] 11+ messages in thread* [PATCH bpf-next v12 3/8] bpf: Refactor reporting log_true_size for prog_load
2026-04-20 14:17 [PATCH bpf-next v12 0/8] bpf: Extend BPF syscall with common attributes support Leon Hwang
2026-04-20 14:17 ` [PATCH bpf-next v12 1/8] " Leon Hwang
2026-04-20 14:17 ` [PATCH bpf-next v12 2/8] libbpf: Add support for extended BPF syscall Leon Hwang
@ 2026-04-20 14:17 ` Leon Hwang
2026-04-20 14:18 ` [PATCH bpf-next v12 4/8] bpf: Add syscall common attributes support " Leon Hwang
` (4 subsequent siblings)
7 siblings, 0 replies; 11+ messages in thread
From: Leon Hwang @ 2026-04-20 14:17 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Daniel Borkmann, John Fastabend,
Andrii Nakryiko, Martin KaFai Lau, Eduard Zingerman, Song Liu,
Yonghong Song, KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa,
Shuah Khan, Christian Brauner, Seth Forshee, Yuichiro Tsuji,
Andrey Albershteyn, Leon Hwang, Willem de Bruijn, Jason Xing,
Tao Chen, Mykyta Yatsenko, Kumar Kartikeya Dwivedi,
Anton Protopopov, Amery Hung, Rong Tao, linux-kernel, linux-api,
linux-kselftest, kernel-patches-bot
The next commit will add support for reporting logs via extended common
attributes, including 'log_true_size'.
To prepare for that, refactor the 'log_true_size' reporting logic by
introducing a new struct bpf_log_attr to encapsulate log-related behavior:
* bpf_log_attr_init(): initialize log fields, which will support
extended common attributes in the next commit.
* bpf_log_attr_finalize(): handle log finalization and write back
'log_true_size' to userspace.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
---
include/linux/bpf.h | 4 +++-
include/linux/bpf_verifier.h | 12 ++++++++++++
kernel/bpf/log.c | 29 +++++++++++++++++++++++++++++
kernel/bpf/syscall.c | 12 +++++++++---
kernel/bpf/verifier.c | 17 ++++-------------
5 files changed, 57 insertions(+), 17 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 30d35d5fe40b..76b28153224a 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -2912,7 +2912,9 @@ int bpf_check_uarg_tail_zero(bpfptr_t uaddr, size_t expected_size,
size_t actual_size);
/* verify correctness of eBPF program */
-int bpf_check(struct bpf_prog **fp, union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size);
+struct bpf_log_attr;
+int bpf_check(struct bpf_prog **fp, union bpf_attr *attr, bpfptr_t uattr,
+ struct bpf_log_attr *attr_log);
#ifndef CONFIG_BPF_JIT_ALWAYS_ON
void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth);
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index 36bfd96d4563..1162b5492841 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -647,6 +647,18 @@ static inline bool bpf_verifier_log_needed(const struct bpf_verifier_log *log)
return log && log->level;
}
+struct bpf_log_attr {
+ char __user *ubuf;
+ u32 size;
+ u32 level;
+ u32 offsetof_true_size;
+ bpfptr_t uattr;
+};
+
+int bpf_log_attr_init(struct bpf_log_attr *log, u64 log_buf, u32 log_size, u32 log_level,
+ u32 offsetof_log_true_size, bpfptr_t uattr);
+int bpf_log_attr_finalize(struct bpf_log_attr *attr, struct bpf_verifier_log *log);
+
#define BPF_MAX_SUBPROGS 256
struct bpf_subprog_arg_info {
diff --git a/kernel/bpf/log.c b/kernel/bpf/log.c
index 37d72b052192..9c5c755d5972 100644
--- a/kernel/bpf/log.c
+++ b/kernel/bpf/log.c
@@ -865,3 +865,32 @@ void print_insn_state(struct bpf_verifier_env *env, const struct bpf_verifier_st
}
print_verifier_state(env, vstate, frameno, false);
}
+
+int bpf_log_attr_init(struct bpf_log_attr *log, u64 log_buf, u32 log_size, u32 log_level,
+ u32 offsetof_log_true_size, bpfptr_t uattr)
+{
+ char __user *ubuf = u64_to_user_ptr(log_buf);
+
+ memset(log, 0, sizeof(*log));
+ log->ubuf = ubuf;
+ log->size = log_size;
+ log->level = log_level;
+ log->offsetof_true_size = offsetof_log_true_size;
+ log->uattr = uattr;
+ return 0;
+}
+
+int bpf_log_attr_finalize(struct bpf_log_attr *attr, struct bpf_verifier_log *log)
+{
+ u32 log_true_size;
+ int err;
+
+ err = bpf_vlog_finalize(log, &log_true_size);
+
+ if (attr->offsetof_true_size &&
+ copy_to_bpfptr_offset(attr->uattr, attr->offsetof_true_size, &log_true_size,
+ sizeof(log_true_size)))
+ return -EFAULT;
+
+ return err;
+}
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 5bf84ea21bf5..b560dab9bfa8 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2861,7 +2861,7 @@ static int bpf_prog_mark_insn_arrays_ready(struct bpf_prog *prog)
/* last field in 'union bpf_attr' used by this command */
#define BPF_PROG_LOAD_LAST_FIELD keyring_id
-static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
+static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, struct bpf_log_attr *attr_log)
{
enum bpf_prog_type type = attr->prog_type;
struct bpf_prog *prog, *dst_prog = NULL;
@@ -3079,7 +3079,7 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
goto free_prog_sec;
/* run eBPF verifier */
- err = bpf_check(&prog, attr, uattr, uattr_size);
+ err = bpf_check(&prog, attr, uattr, attr_log);
if (err < 0)
goto free_used_maps;
@@ -6214,6 +6214,8 @@ static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size,
bpfptr_t uattr_common, unsigned int size_common)
{
struct bpf_common_attr attr_common;
+ u32 offsetof_log_true_size = 0;
+ struct bpf_log_attr attr_log;
union bpf_attr attr;
int err;
@@ -6265,7 +6267,11 @@ static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size,
err = map_freeze(&attr);
break;
case BPF_PROG_LOAD:
- err = bpf_prog_load(&attr, uattr, size);
+ if (size >= offsetofend(union bpf_attr, log_true_size))
+ offsetof_log_true_size = offsetof(union bpf_attr, log_true_size);
+ err = bpf_log_attr_init(&attr_log, attr.log_buf, attr.log_size, attr.log_level,
+ offsetof_log_true_size, uattr);
+ err = err ?: bpf_prog_load(&attr, uattr, &attr_log);
break;
case BPF_OBJ_PIN:
err = bpf_obj_pin(&attr);
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 594260c1f382..668a3628013e 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -26526,12 +26526,12 @@ static int compute_scc(struct bpf_verifier_env *env)
return err;
}
-int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u32 uattr_size)
+int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr,
+ struct bpf_log_attr *attr_log)
{
u64 start_time = ktime_get_ns();
struct bpf_verifier_env *env;
int i, len, ret = -EINVAL, err;
- u32 log_true_size;
bool is_priv;
BTF_TYPE_EMIT(enum bpf_features);
@@ -26578,9 +26578,7 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u3
/* user could have requested verbose verifier output
* and supplied buffer to store the verification trace
*/
- ret = bpf_vlog_init(&env->log, attr->log_level,
- (char __user *) (unsigned long) attr->log_buf,
- attr->log_size);
+ ret = bpf_vlog_init(&env->log, attr_log->level, attr_log->ubuf, attr_log->size);
if (ret)
goto err_unlock;
@@ -26742,17 +26740,10 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u3
env->prog->aux->verified_insns = env->insn_processed;
/* preserve original error even if log finalization is successful */
- err = bpf_vlog_finalize(&env->log, &log_true_size);
+ err = bpf_log_attr_finalize(attr_log, &env->log);
if (err)
ret = err;
- if (uattr_size >= offsetofend(union bpf_attr, log_true_size) &&
- copy_to_bpfptr_offset(uattr, offsetof(union bpf_attr, log_true_size),
- &log_true_size, sizeof(log_true_size))) {
- ret = -EFAULT;
- goto err_release_maps;
- }
-
if (ret)
goto err_release_maps;
--
2.53.0
^ permalink raw reply related [flat|nested] 11+ messages in thread* [PATCH bpf-next v12 4/8] bpf: Add syscall common attributes support for prog_load
2026-04-20 14:17 [PATCH bpf-next v12 0/8] bpf: Extend BPF syscall with common attributes support Leon Hwang
` (2 preceding siblings ...)
2026-04-20 14:17 ` [PATCH bpf-next v12 3/8] bpf: Refactor reporting log_true_size for prog_load Leon Hwang
@ 2026-04-20 14:18 ` Leon Hwang
2026-04-20 14:18 ` [PATCH bpf-next v12 5/8] bpf: Add syscall common attributes support for btf_load Leon Hwang
` (3 subsequent siblings)
7 siblings, 0 replies; 11+ messages in thread
From: Leon Hwang @ 2026-04-20 14:18 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Daniel Borkmann, John Fastabend,
Andrii Nakryiko, Martin KaFai Lau, Eduard Zingerman, Song Liu,
Yonghong Song, KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa,
Shuah Khan, Christian Brauner, Seth Forshee, Yuichiro Tsuji,
Andrey Albershteyn, Leon Hwang, Willem de Bruijn, Jason Xing,
Tao Chen, Mykyta Yatsenko, Kumar Kartikeya Dwivedi,
Anton Protopopov, Amery Hung, Rong Tao, linux-kernel, linux-api,
linux-kselftest, kernel-patches-bot
BPF_PROG_LOAD can now take log parameters from both union bpf_attr and
struct bpf_common_attr. The merge rules are:
- if both sides provide a complete log tuple (buf/size/level) and they
match, use it;
- if only one side provides log parameters, use that one;
- if both sides provide complete tuples but they differ, return -EINVAL.
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
---
include/linux/bpf_verifier.h | 3 ++-
kernel/bpf/log.c | 34 +++++++++++++++++++++++++++-------
kernel/bpf/syscall.c | 3 ++-
3 files changed, 31 insertions(+), 9 deletions(-)
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index 1162b5492841..9045dc88c5b6 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -656,7 +656,8 @@ struct bpf_log_attr {
};
int bpf_log_attr_init(struct bpf_log_attr *log, u64 log_buf, u32 log_size, u32 log_level,
- u32 offsetof_log_true_size, bpfptr_t uattr);
+ u32 offsetof_log_true_size, bpfptr_t uattr, struct bpf_common_attr *common,
+ bpfptr_t uattr_common, u32 size_common);
int bpf_log_attr_finalize(struct bpf_log_attr *attr, struct bpf_verifier_log *log);
#define BPF_MAX_SUBPROGS 256
diff --git a/kernel/bpf/log.c b/kernel/bpf/log.c
index 9c5c755d5972..dc8734e27752 100644
--- a/kernel/bpf/log.c
+++ b/kernel/bpf/log.c
@@ -13,17 +13,17 @@
#define verbose(env, fmt, args...) bpf_verifier_log_write(env, fmt, ##args)
-static bool bpf_verifier_log_attr_valid(const struct bpf_verifier_log *log)
+static bool bpf_verifier_log_attr_valid(u32 log_level, char __user *log_buf, u32 log_size)
{
/* ubuf and len_total should both be specified (or not) together */
- if (!!log->ubuf != !!log->len_total)
+ if (!!log_buf != !!log_size)
return false;
/* log buf without log_level is meaningless */
- if (log->ubuf && log->level == 0)
+ if (log_buf && log_level == 0)
return false;
- if (log->level & ~BPF_LOG_MASK)
+ if (log_level & ~BPF_LOG_MASK)
return false;
- if (log->len_total > UINT_MAX >> 2)
+ if (log_size > UINT_MAX >> 2)
return false;
return true;
}
@@ -36,7 +36,7 @@ int bpf_vlog_init(struct bpf_verifier_log *log, u32 log_level,
log->len_total = log_size;
/* log attributes have to be sane */
- if (!bpf_verifier_log_attr_valid(log))
+ if (!bpf_verifier_log_attr_valid(log_level, log_buf, log_size))
return -EINVAL;
return 0;
@@ -867,16 +867,36 @@ void print_insn_state(struct bpf_verifier_env *env, const struct bpf_verifier_st
}
int bpf_log_attr_init(struct bpf_log_attr *log, u64 log_buf, u32 log_size, u32 log_level,
- u32 offsetof_log_true_size, bpfptr_t uattr)
+ u32 offsetof_log_true_size, bpfptr_t uattr, struct bpf_common_attr *common,
+ bpfptr_t uattr_common, u32 size_common)
{
+ char __user *ubuf_common = u64_to_user_ptr(common->log_buf);
char __user *ubuf = u64_to_user_ptr(log_buf);
+ if (!bpf_verifier_log_attr_valid(common->log_level, ubuf_common, common->log_size) ||
+ !bpf_verifier_log_attr_valid(log_level, ubuf, log_size))
+ return -EINVAL;
+
+ if (ubuf && ubuf_common && (ubuf != ubuf_common || log_size != common->log_size ||
+ log_level != common->log_level))
+ return -EINVAL;
+
memset(log, 0, sizeof(*log));
log->ubuf = ubuf;
log->size = log_size;
log->level = log_level;
log->offsetof_true_size = offsetof_log_true_size;
log->uattr = uattr;
+
+ if (!ubuf && ubuf_common) {
+ log->ubuf = ubuf_common;
+ log->size = common->log_size;
+ log->level = common->log_level;
+ log->uattr = uattr_common;
+ log->offsetof_true_size = 0;
+ if (size_common >= offsetofend(struct bpf_common_attr, log_true_size))
+ log->offsetof_true_size = offsetof(struct bpf_common_attr, log_true_size);
+ }
return 0;
}
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index b560dab9bfa8..1eb15a51c7dc 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -6270,7 +6270,8 @@ static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size,
if (size >= offsetofend(union bpf_attr, log_true_size))
offsetof_log_true_size = offsetof(union bpf_attr, log_true_size);
err = bpf_log_attr_init(&attr_log, attr.log_buf, attr.log_size, attr.log_level,
- offsetof_log_true_size, uattr);
+ offsetof_log_true_size, uattr, &attr_common, uattr_common,
+ size_common);
err = err ?: bpf_prog_load(&attr, uattr, &attr_log);
break;
case BPF_OBJ_PIN:
--
2.53.0
^ permalink raw reply related [flat|nested] 11+ messages in thread* [PATCH bpf-next v12 5/8] bpf: Add syscall common attributes support for btf_load
2026-04-20 14:17 [PATCH bpf-next v12 0/8] bpf: Extend BPF syscall with common attributes support Leon Hwang
` (3 preceding siblings ...)
2026-04-20 14:18 ` [PATCH bpf-next v12 4/8] bpf: Add syscall common attributes support " Leon Hwang
@ 2026-04-20 14:18 ` Leon Hwang
2026-04-20 14:56 ` bot+bpf-ci
2026-04-20 14:18 ` [PATCH bpf-next v12 6/8] bpf: Add syscall common attributes support for map_create Leon Hwang
` (2 subsequent siblings)
7 siblings, 1 reply; 11+ messages in thread
From: Leon Hwang @ 2026-04-20 14:18 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Daniel Borkmann, John Fastabend,
Andrii Nakryiko, Martin KaFai Lau, Eduard Zingerman, Song Liu,
Yonghong Song, KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa,
Shuah Khan, Christian Brauner, Seth Forshee, Yuichiro Tsuji,
Andrey Albershteyn, Leon Hwang, Willem de Bruijn, Jason Xing,
Tao Chen, Mykyta Yatsenko, Kumar Kartikeya Dwivedi,
Anton Protopopov, Amery Hung, Rong Tao, linux-kernel, linux-api,
linux-kselftest, kernel-patches-bot
BPF_BTF_LOAD can now take log parameters from both union bpf_attr and
struct bpf_common_attr, with the same merge rules as BPF_PROG_LOAD:
- if both sides provide a complete log tuple (buf/size/level) and they
match, use it;
- if only one side provides log parameters, use that one;
- if both sides provide complete tuples but they differ, return -EINVAL.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
---
include/linux/btf.h | 3 ++-
kernel/bpf/btf.c | 30 +++++++-----------------------
kernel/bpf/syscall.c | 11 ++++++++---
3 files changed, 17 insertions(+), 27 deletions(-)
diff --git a/include/linux/btf.h b/include/linux/btf.h
index 48108471c5b1..f64d87315c5f 100644
--- a/include/linux/btf.h
+++ b/include/linux/btf.h
@@ -145,7 +145,8 @@ const char *btf_get_name(const struct btf *btf);
void btf_get(struct btf *btf);
void btf_put(struct btf *btf);
const struct btf_header *btf_header(const struct btf *btf);
-int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr, u32 uattr_sz);
+struct bpf_log_attr;
+int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr, struct bpf_log_attr *attr_log);
struct btf *btf_get_by_fd(int fd);
int btf_get_info_by_fd(const struct btf *btf,
const union bpf_attr *attr,
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index a62d78581207..9f69ef774a0b 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -5914,25 +5914,10 @@ static int btf_check_type_tags(struct btf_verifier_env *env,
return 0;
}
-static int finalize_log(struct bpf_verifier_log *log, bpfptr_t uattr, u32 uattr_size)
-{
- u32 log_true_size;
- int err;
-
- err = bpf_vlog_finalize(log, &log_true_size);
-
- if (uattr_size >= offsetofend(union bpf_attr, btf_log_true_size) &&
- copy_to_bpfptr_offset(uattr, offsetof(union bpf_attr, btf_log_true_size),
- &log_true_size, sizeof(log_true_size)))
- err = -EFAULT;
-
- return err;
-}
-
-static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
+static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr,
+ struct bpf_log_attr *attr_log)
{
bpfptr_t btf_data = make_bpfptr(attr->btf, uattr.is_kernel);
- char __user *log_ubuf = u64_to_user_ptr(attr->btf_log_buf);
struct btf_struct_metas *struct_meta_tab;
struct btf_verifier_env *env = NULL;
struct btf *btf = NULL;
@@ -5949,8 +5934,7 @@ static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr, u32 uat
/* user could have requested verbose verifier output
* and supplied buffer to store the verification trace
*/
- err = bpf_vlog_init(&env->log, attr->btf_log_level,
- log_ubuf, attr->btf_log_size);
+ err = bpf_vlog_init(&env->log, attr_log->level, attr_log->ubuf, attr_log->size);
if (err)
goto errout_free;
@@ -6015,7 +5999,7 @@ static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr, u32 uat
}
}
- err = finalize_log(&env->log, uattr, uattr_size);
+ err = bpf_log_attr_finalize(attr_log, &env->log);
if (err)
goto errout_free;
@@ -6027,7 +6011,7 @@ static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr, u32 uat
btf_free_struct_meta_tab(btf);
errout:
/* overwrite err with -ENOSPC or -EFAULT */
- ret = finalize_log(&env->log, uattr, uattr_size);
+ ret = bpf_log_attr_finalize(attr_log, &env->log);
if (ret)
err = ret;
errout_free:
@@ -8196,12 +8180,12 @@ static int __btf_new_fd(struct btf *btf)
return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
}
-int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
+int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr, struct bpf_log_attr *attr_log)
{
struct btf *btf;
int ret;
- btf = btf_parse(attr, uattr, uattr_size);
+ btf = btf_parse(attr, uattr, attr_log);
if (IS_ERR(btf))
return PTR_ERR(btf);
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 1eb15a51c7dc..06aea4e499a1 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -5473,7 +5473,7 @@ static int bpf_obj_get_info_by_fd(const union bpf_attr *attr,
#define BPF_BTF_LOAD_LAST_FIELD btf_token_fd
-static int bpf_btf_load(const union bpf_attr *attr, bpfptr_t uattr, __u32 uattr_size)
+static int bpf_btf_load(const union bpf_attr *attr, bpfptr_t uattr, struct bpf_log_attr *attr_log)
{
struct bpf_token *token = NULL;
@@ -5500,7 +5500,7 @@ static int bpf_btf_load(const union bpf_attr *attr, bpfptr_t uattr, __u32 uattr_
bpf_token_put(token);
- return btf_new_fd(attr, uattr, uattr_size);
+ return btf_new_fd(attr, uattr, attr_log);
}
#define BPF_BTF_GET_FD_BY_ID_LAST_FIELD fd_by_id_token_fd
@@ -6317,7 +6317,12 @@ static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size,
err = bpf_raw_tracepoint_open(&attr);
break;
case BPF_BTF_LOAD:
- err = bpf_btf_load(&attr, uattr, size);
+ if (size >= offsetofend(union bpf_attr, btf_log_true_size))
+ offsetof_log_true_size = offsetof(union bpf_attr, btf_log_true_size);
+ err = bpf_log_attr_init(&attr_log, attr.btf_log_buf, attr.btf_log_size,
+ attr.btf_log_level, offsetof_log_true_size, uattr,
+ &attr_common, uattr_common, size_common);
+ err = err ?: bpf_btf_load(&attr, uattr, &attr_log);
break;
case BPF_BTF_GET_FD_BY_ID:
err = bpf_btf_get_fd_by_id(&attr);
--
2.53.0
^ permalink raw reply related [flat|nested] 11+ messages in thread* Re: [PATCH bpf-next v12 5/8] bpf: Add syscall common attributes support for btf_load
2026-04-20 14:18 ` [PATCH bpf-next v12 5/8] bpf: Add syscall common attributes support for btf_load Leon Hwang
@ 2026-04-20 14:56 ` bot+bpf-ci
0 siblings, 0 replies; 11+ messages in thread
From: bot+bpf-ci @ 2026-04-20 14:56 UTC (permalink / raw)
To: leon.hwang, bpf
Cc: ast, daniel, john.fastabend, andrii, martin.lau, eddyz87, song,
yonghong.song, kpsingh, sdf, haoluo, jolsa, shuah, brauner,
sforshee, yuichtsu, aalbersh, leon.hwang, willemb,
kerneljasonxing, chen.dylane, yatsenko, memxor, a.s.protopopov,
ameryhung, rongtao, linux-kernel, linux-api, linux-kselftest,
kernel-patches-bot, ast, andrii, daniel, martin.lau, eddyz87,
yonghong.song, clm, ihor.solodrai
[-- Attachment #1: Type: text/plain, Size: 1644 bytes --]
> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> index 1eb15a51c7dc..06aea4e499a1 100644
> --- a/kernel/bpf/syscall.c
> +++ b/kernel/bpf/syscall.c
[ ... ]
> @@ -6317,7 +6317,12 @@ static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size,
> err = bpf_raw_tracepoint_open(&attr);
> break;
> case BPF_BTF_LOAD:
> - err = bpf_btf_load(&attr, uattr, size);
> + if (size >= offsetofend(union bpf_attr, btf_log_true_size))
> + offsetof_log_true_size = offsetof(union bpf_attr, btf_log_true_size);
> + err = bpf_log_attr_init(&attr_log, attr.btf_log_buf, attr.btf_log_size,
> + attr.btf_log_level, offsetof_log_true_size, uattr,
> + &attr_common, uattr_common, size_common);
> + err = err ?: bpf_btf_load(&attr, uattr, &attr_log);
Should the log_true_size offset be set only for user space calls? In v10
review, Andrii Nakryiko noted that log_true_size should only be set for
user space, not kernel space calls.
https://lore.kernel.org/bpf/CAEf4BzY3GA+860RODLaXqqO3j5AgJ24pmKU1yv3+gHJpy0DvNA@mail.gmail.com/
The current code does not check uattr.is_kernel before setting
offsetof_log_true_size. This could cause issues when bpf_sys_bpf() calls
__sys_bpf() with KERNEL_BPFPTR, as it would attempt to write log_true_size
to a kernel pointer instead of a user space pointer.
> break;
> case BPF_BTF_GET_FD_BY_ID:
> err = bpf_btf_get_fd_by_id(&attr);
---
AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md
CI run summary: https://github.com/kernel-patches/bpf/actions/runs/24672239158
^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH bpf-next v12 6/8] bpf: Add syscall common attributes support for map_create
2026-04-20 14:17 [PATCH bpf-next v12 0/8] bpf: Extend BPF syscall with common attributes support Leon Hwang
` (4 preceding siblings ...)
2026-04-20 14:18 ` [PATCH bpf-next v12 5/8] bpf: Add syscall common attributes support for btf_load Leon Hwang
@ 2026-04-20 14:18 ` Leon Hwang
2026-04-20 14:56 ` bot+bpf-ci
2026-04-20 14:18 ` [PATCH bpf-next v12 7/8] libbpf: " Leon Hwang
2026-04-20 14:18 ` [PATCH bpf-next v12 8/8] selftests/bpf: Add tests to verify map create failure log Leon Hwang
7 siblings, 1 reply; 11+ messages in thread
From: Leon Hwang @ 2026-04-20 14:18 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Daniel Borkmann, John Fastabend,
Andrii Nakryiko, Martin KaFai Lau, Eduard Zingerman, Song Liu,
Yonghong Song, KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa,
Shuah Khan, Christian Brauner, Seth Forshee, Yuichiro Tsuji,
Andrey Albershteyn, Leon Hwang, Willem de Bruijn, Jason Xing,
Tao Chen, Mykyta Yatsenko, Kumar Kartikeya Dwivedi,
Anton Protopopov, Amery Hung, Rong Tao, linux-kernel, linux-api,
linux-kselftest, kernel-patches-bot
Many BPF_MAP_CREATE validation failures currently return -EINVAL without
any explanation to userspace.
Plumb common syscall log attributes into map_create(), create a verifier
log from bpf_common_attr::log_buf/log_size/log_level, and report
map-creation failure reasons through that buffer.
This improves debuggability by allowing userspace to inspect why map
creation failed and read back log_true_size from common attributes.
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
---
include/linux/bpf_verifier.h | 3 ++
kernel/bpf/log.c | 30 +++++++++++++++++
kernel/bpf/syscall.c | 65 ++++++++++++++++++++++++++++++------
3 files changed, 88 insertions(+), 10 deletions(-)
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index 9045dc88c5b6..9f565f7fd3f9 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -658,6 +658,9 @@ struct bpf_log_attr {
int bpf_log_attr_init(struct bpf_log_attr *log, u64 log_buf, u32 log_size, u32 log_level,
u32 offsetof_log_true_size, bpfptr_t uattr, struct bpf_common_attr *common,
bpfptr_t uattr_common, u32 size_common);
+struct bpf_verifier_log *bpf_log_attr_create_vlog(struct bpf_log_attr *attr_log,
+ struct bpf_common_attr *common, bpfptr_t uattr,
+ u32 size);
int bpf_log_attr_finalize(struct bpf_log_attr *attr, struct bpf_verifier_log *log);
#define BPF_MAX_SUBPROGS 256
diff --git a/kernel/bpf/log.c b/kernel/bpf/log.c
index dc8734e27752..0c972f577b60 100644
--- a/kernel/bpf/log.c
+++ b/kernel/bpf/log.c
@@ -900,6 +900,36 @@ int bpf_log_attr_init(struct bpf_log_attr *log, u64 log_buf, u32 log_size, u32 l
return 0;
}
+
+struct bpf_verifier_log *bpf_log_attr_create_vlog(struct bpf_log_attr *attr_log,
+ struct bpf_common_attr *common, bpfptr_t uattr,
+ u32 size)
+{
+ struct bpf_verifier_log *log;
+ int err;
+
+ memset(attr_log, 0, sizeof(*attr_log));
+ attr_log->uattr = uattr;
+ if (size >= offsetofend(struct bpf_common_attr, log_true_size))
+ attr_log->offsetof_true_size = offsetof(struct bpf_common_attr, log_true_size);
+
+ if (!common->log_buf)
+ return NULL;
+
+ log = kzalloc_obj(*log, GFP_KERNEL);
+ if (!log)
+ return ERR_PTR(-ENOMEM);
+
+ err = bpf_vlog_init(log, common->log_level, u64_to_user_ptr(common->log_buf),
+ common->log_size);
+ if (err) {
+ kfree(log);
+ return ERR_PTR(err);
+ }
+
+ return log;
+}
+
int bpf_log_attr_finalize(struct bpf_log_attr *attr, struct bpf_verifier_log *log)
{
u32 log_true_size;
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 06aea4e499a1..39f4d4b00469 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1359,7 +1359,7 @@ static int map_check_btf(struct bpf_map *map, struct bpf_token *token,
#define BPF_MAP_CREATE_LAST_FIELD excl_prog_hash_size
/* called via syscall */
-static int map_create(union bpf_attr *attr, bpfptr_t uattr)
+static int __map_create(union bpf_attr *attr, bpfptr_t uattr, struct bpf_verifier_log *log)
{
const struct bpf_map_ops *ops;
struct bpf_token *token = NULL;
@@ -1371,8 +1371,10 @@ static int map_create(union bpf_attr *attr, bpfptr_t uattr)
int err;
err = CHECK_ATTR(BPF_MAP_CREATE);
- if (err)
+ if (err) {
+ bpf_log(log, "Invalid attr.\n");
return -EINVAL;
+ }
/* check BPF_F_TOKEN_FD flag, remember if it's set, and then clear it
* to avoid per-map type checks tripping on unknown flag
@@ -1381,17 +1383,25 @@ static int map_create(union bpf_attr *attr, bpfptr_t uattr)
attr->map_flags &= ~BPF_F_TOKEN_FD;
if (attr->btf_vmlinux_value_type_id) {
- if (attr->map_type != BPF_MAP_TYPE_STRUCT_OPS ||
- attr->btf_key_type_id || attr->btf_value_type_id)
+ if (attr->map_type != BPF_MAP_TYPE_STRUCT_OPS) {
+ bpf_log(log, "btf_vmlinux_value_type_id can only be used with struct_ops maps.\n");
return -EINVAL;
+ }
+ if (attr->btf_key_type_id || attr->btf_value_type_id) {
+ bpf_log(log, "btf_vmlinux_value_type_id is mutually exclusive with btf_key_type_id and btf_value_type_id.\n");
+ return -EINVAL;
+ }
} else if (attr->btf_key_type_id && !attr->btf_value_type_id) {
+ bpf_log(log, "Invalid btf_value_type_id.\n");
return -EINVAL;
}
if (attr->map_type != BPF_MAP_TYPE_BLOOM_FILTER &&
attr->map_type != BPF_MAP_TYPE_ARENA &&
- attr->map_extra != 0)
+ attr->map_extra != 0) {
+ bpf_log(log, "Invalid map_extra.\n");
return -EINVAL;
+ }
f_flags = bpf_get_file_flag(attr->map_flags);
if (f_flags < 0)
@@ -1399,13 +1409,17 @@ static int map_create(union bpf_attr *attr, bpfptr_t uattr)
if (numa_node != NUMA_NO_NODE &&
((unsigned int)numa_node >= nr_node_ids ||
- !node_online(numa_node)))
+ !node_online(numa_node))) {
+ bpf_log(log, "Invalid numa_node.\n");
return -EINVAL;
+ }
/* find map type and init map: hashtable vs rbtree vs bloom vs ... */
map_type = attr->map_type;
- if (map_type >= ARRAY_SIZE(bpf_map_types))
+ if (map_type >= ARRAY_SIZE(bpf_map_types)) {
+ bpf_log(log, "Invalid map_type.\n");
return -EINVAL;
+ }
map_type = array_index_nospec(map_type, ARRAY_SIZE(bpf_map_types));
ops = bpf_map_types[map_type];
if (!ops)
@@ -1423,8 +1437,10 @@ static int map_create(union bpf_attr *attr, bpfptr_t uattr)
if (token_flag) {
token = bpf_token_get_from_fd(attr->map_token_fd);
- if (IS_ERR(token))
+ if (IS_ERR(token)) {
+ bpf_log(log, "Invalid map_token_fd.\n");
return PTR_ERR(token);
+ }
/* if current token doesn't grant map creation permissions,
* then we can't use this token, so ignore it and rely on
@@ -1507,8 +1523,10 @@ static int map_create(union bpf_attr *attr, bpfptr_t uattr)
err = bpf_obj_name_cpy(map->name, attr->map_name,
sizeof(attr->map_name));
- if (err < 0)
+ if (err < 0) {
+ bpf_log(log, "Invalid map_name.\n");
goto free_map;
+ }
preempt_disable();
map->cookie = gen_cookie_next(&bpf_map_cookie);
@@ -1531,6 +1549,7 @@ static int map_create(union bpf_attr *attr, bpfptr_t uattr)
btf = btf_get_by_fd(attr->btf_fd);
if (IS_ERR(btf)) {
+ bpf_log(log, "Invalid btf_fd.\n");
err = PTR_ERR(btf);
goto free_map;
}
@@ -1558,6 +1577,7 @@ static int map_create(union bpf_attr *attr, bpfptr_t uattr)
bpfptr_t uprog_hash = make_bpfptr(attr->excl_prog_hash, uattr.is_kernel);
if (attr->excl_prog_hash_size != SHA256_DIGEST_SIZE) {
+ bpf_log(log, "Invalid excl_prog_hash_size.\n");
err = -EINVAL;
goto free_map;
}
@@ -1573,6 +1593,7 @@ static int map_create(union bpf_attr *attr, bpfptr_t uattr)
goto free_map;
}
} else if (attr->excl_prog_hash_size) {
+ bpf_log(log, "Invalid excl_prog_hash_size.\n");
err = -EINVAL;
goto free_map;
}
@@ -1611,6 +1632,30 @@ static int map_create(union bpf_attr *attr, bpfptr_t uattr)
return err;
}
+static int map_create(union bpf_attr *attr, bpfptr_t uattr, struct bpf_common_attr *attr_common,
+ bpfptr_t uattr_common, u32 size_common)
+{
+ struct bpf_verifier_log *log;
+ struct bpf_log_attr attr_log;
+ int err, ret;
+
+ log = bpf_log_attr_create_vlog(&attr_log, attr_common, uattr_common, size_common);
+ if (IS_ERR(log))
+ return PTR_ERR(log);
+
+ err = __map_create(attr, uattr, log);
+ if (err >= 0)
+ goto free;
+
+ ret = bpf_log_attr_finalize(&attr_log, log);
+ if (ret)
+ err = ret;
+
+free:
+ kfree(log);
+ return err;
+}
+
void bpf_map_inc(struct bpf_map *map)
{
atomic64_inc(&map->refcnt);
@@ -6249,7 +6294,7 @@ static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size,
switch (cmd) {
case BPF_MAP_CREATE:
- err = map_create(&attr, uattr);
+ err = map_create(&attr, uattr, &attr_common, uattr_common, size_common);
break;
case BPF_MAP_LOOKUP_ELEM:
err = map_lookup_elem(&attr);
--
2.53.0
^ permalink raw reply related [flat|nested] 11+ messages in thread* Re: [PATCH bpf-next v12 6/8] bpf: Add syscall common attributes support for map_create
2026-04-20 14:18 ` [PATCH bpf-next v12 6/8] bpf: Add syscall common attributes support for map_create Leon Hwang
@ 2026-04-20 14:56 ` bot+bpf-ci
0 siblings, 0 replies; 11+ messages in thread
From: bot+bpf-ci @ 2026-04-20 14:56 UTC (permalink / raw)
To: leon.hwang, bpf
Cc: ast, daniel, john.fastabend, andrii, martin.lau, eddyz87, song,
yonghong.song, kpsingh, sdf, haoluo, jolsa, shuah, brauner,
sforshee, yuichtsu, aalbersh, leon.hwang, willemb,
kerneljasonxing, chen.dylane, yatsenko, memxor, a.s.protopopov,
ameryhung, rongtao, linux-kernel, linux-api, linux-kselftest,
kernel-patches-bot, ast, andrii, daniel, martin.lau, eddyz87,
yonghong.song, clm, ihor.solodrai
[-- Attachment #1: Type: text/plain, Size: 3737 bytes --]
> diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
> index dbe321aa8591..34500f81db6e 100644
> --- a/include/linux/bpf_verifier.h
> +++ b/include/linux/bpf_verifier.h
> @@ -710,6 +710,9 @@ struct bpf_log_attr {
> int bpf_log_attr_init(struct bpf_log_attr *log, u64 log_buf, u32 log_size, u32 log_level,
> u32 offsetof_log_true_size, bpfptr_t uattr, struct bpf_common_attr *common,
> bpfptr_t uattr_common, u32 size_common);
> +struct bpf_verifier_log *bpf_log_attr_create_vlog(struct bpf_log_attr *attr_log,
> + struct bpf_common_attr *common, bpfptr_t uattr,
> + u32 size);
> int bpf_log_attr_finalize(struct bpf_log_attr *attr, struct bpf_verifier_log *log);
>
> #define BPF_MAX_SUBPROGS 256
> diff --git a/kernel/bpf/log.c b/kernel/bpf/log.c
> index dffe3a0180a7..5a977a52ef61 100644
> --- a/kernel/bpf/log.c
> +++ b/kernel/bpf/log.c
> @@ -860,6 +860,36 @@ int bpf_log_attr_init(struct bpf_log_attr *log, u64 log_buf, u32 log_size, u32 l
> return 0;
> }
>
> +
> +struct bpf_verifier_log *bpf_log_attr_create_vlog(struct bpf_log_attr *attr_log,
> + struct bpf_common_attr *common, bpfptr_t uattr,
> + u32 size)
> +{
> + struct bpf_verifier_log *log;
> + int err;
> +
> + memset(attr_log, 0, sizeof(*attr_log));
> + attr_log->uattr = uattr;
> + if (size >= offsetofend(struct bpf_common_attr, log_true_size))
> + attr_log->offsetof_true_size = offsetof(struct bpf_common_attr, log_true_size);
> +
> + if (!common->log_buf)
> + return NULL;
Does this skip validation that bpf_log_attr_init() performs?
The sibling helper bpf_log_attr_init() validates struct bpf_common_attr
fields via bpf_verifier_log_attr_valid() unconditionally:
kernel/bpf/log.c:bpf_log_attr_init() {
if (!bpf_verifier_log_attr_valid(common->log_level, ubuf_common, common->log_size) ||
!bpf_verifier_log_attr_valid(log_level, ubuf, log_size))
return -EINVAL;
}
This returns -EINVAL for combinations like (log_buf==0 && log_size!=0)
or (log_buf==0 && log_level!=0), enforced by:
kernel/bpf/log.c:bpf_verifier_log_attr_valid() {
/* ubuf and len_total should both be specified (or not) together */
if (!!log_buf != !!log_size)
return false;
if (log_buf && log_level == 0)
return false;
if (log_level & ~BPF_LOG_MASK)
return false;
if (log_size > UINT_MAX >> 2)
return false;
}
When bpf_log_attr_create_vlog() returns early because common->log_buf == 0,
these four checks are skipped entirely. When common->log_buf != 0, the
checks run later via bpf_vlog_init().
This creates an ABI validation inconsistency: BPF_PROG_LOAD and BPF_BTF_LOAD
reject (log_buf==0 && log_size!=0) with -EINVAL, but BPF_MAP_CREATE
silently accepts it. Userspace passing the same invalid attribute
combination receives different results depending on the syscall command.
Should bpf_log_attr_create_vlog() call
bpf_verifier_log_attr_valid(common->log_level, u64_to_user_ptr(common->log_buf), common->log_size)
before the early return, and return ERR_PTR(-EINVAL) on failure?
> +
> + log = kzalloc_obj(*log, GFP_KERNEL);
> + if (!log)
> + return ERR_PTR(-ENOMEM);
> +
> + err = bpf_vlog_init(log, common->log_level, u64_to_user_ptr(common->log_buf),
> + common->log_size);
> + if (err) {
> + kfree(log);
> + return ERR_PTR(err);
> + }
> +
> + return log;
> +}
> +
> int bpf_log_attr_finalize(struct bpf_log_attr *attr, struct bpf_verifier_log *log)
> {
> u32 log_true_size;
[ ... ]
---
AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md
CI run summary: https://github.com/kernel-patches/bpf/actions/runs/24672239158
^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH bpf-next v12 7/8] libbpf: Add syscall common attributes support for map_create
2026-04-20 14:17 [PATCH bpf-next v12 0/8] bpf: Extend BPF syscall with common attributes support Leon Hwang
` (5 preceding siblings ...)
2026-04-20 14:18 ` [PATCH bpf-next v12 6/8] bpf: Add syscall common attributes support for map_create Leon Hwang
@ 2026-04-20 14:18 ` Leon Hwang
2026-04-20 14:18 ` [PATCH bpf-next v12 8/8] selftests/bpf: Add tests to verify map create failure log Leon Hwang
7 siblings, 0 replies; 11+ messages in thread
From: Leon Hwang @ 2026-04-20 14:18 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Daniel Borkmann, John Fastabend,
Andrii Nakryiko, Martin KaFai Lau, Eduard Zingerman, Song Liu,
Yonghong Song, KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa,
Shuah Khan, Christian Brauner, Seth Forshee, Yuichiro Tsuji,
Andrey Albershteyn, Leon Hwang, Willem de Bruijn, Jason Xing,
Tao Chen, Mykyta Yatsenko, Kumar Kartikeya Dwivedi,
Anton Protopopov, Amery Hung, Rong Tao, linux-kernel, linux-api,
linux-kselftest, kernel-patches-bot
With the previous commit adding common attribute support for
BPF_MAP_CREATE, users can now retrieve detailed error messages when map
creation fails via the log_buf field.
Introduce struct bpf_log_opts with the following fields:
log_buf, log_size, log_level, and log_true_size.
Extend bpf_map_create_opts with a new field log_opts, allowing users to
capture and inspect log messages on map creation failures.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
---
tools/lib/bpf/bpf.c | 16 +++++++++++++++-
tools/lib/bpf/bpf.h | 17 ++++++++++++++++-
2 files changed, 31 insertions(+), 2 deletions(-)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 9d8740761b7a..483c02cf21d1 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -209,6 +209,9 @@ int bpf_map_create(enum bpf_map_type map_type,
const struct bpf_map_create_opts *opts)
{
const size_t attr_sz = offsetofend(union bpf_attr, excl_prog_hash_size);
+ const size_t attr_common_sz = sizeof(struct bpf_common_attr);
+ struct bpf_common_attr attr_common;
+ struct bpf_log_opts *log_opts;
union bpf_attr attr;
int fd;
@@ -242,7 +245,18 @@ int bpf_map_create(enum bpf_map_type map_type,
attr.excl_prog_hash = ptr_to_u64(OPTS_GET(opts, excl_prog_hash, NULL));
attr.excl_prog_hash_size = OPTS_GET(opts, excl_prog_hash_size, 0);
- fd = sys_bpf_fd(BPF_MAP_CREATE, &attr, attr_sz);
+ log_opts = OPTS_GET(opts, log_opts, NULL);
+ if (log_opts && feat_supported(NULL, FEAT_BPF_SYSCALL_COMMON_ATTRS)) {
+ memset(&attr_common, 0, attr_common_sz);
+ attr_common.log_buf = ptr_to_u64(OPTS_GET(log_opts, buf, NULL));
+ attr_common.log_size = OPTS_GET(log_opts, size, 0);
+ attr_common.log_level = OPTS_GET(log_opts, level, 0);
+ fd = sys_bpf_ext_fd(BPF_MAP_CREATE, &attr, attr_sz, &attr_common, attr_common_sz);
+ OPTS_SET(log_opts, true_size, attr_common.log_true_size);
+ } else {
+ fd = sys_bpf_fd(BPF_MAP_CREATE, &attr, attr_sz);
+ OPTS_SET(log_opts, true_size, 0);
+ }
return libbpf_err_errno(fd);
}
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 2c8e88ddb674..2312900a3263 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -37,6 +37,18 @@ extern "C" {
LIBBPF_API int libbpf_set_memlock_rlim(size_t memlock_bytes);
+struct bpf_log_opts {
+ size_t sz; /* size of this struct for forward/backward compatibility */
+
+ char *buf;
+ __u32 size;
+ __u32 level;
+ __u32 true_size; /* out parameter set by kernel */
+
+ size_t :0;
+};
+#define bpf_log_opts__last_field true_size
+
struct bpf_map_create_opts {
size_t sz; /* size of this struct for forward/backward compatibility */
@@ -57,9 +69,12 @@ struct bpf_map_create_opts {
const void *excl_prog_hash;
__u32 excl_prog_hash_size;
+
+ struct bpf_log_opts *log_opts;
+
size_t :0;
};
-#define bpf_map_create_opts__last_field excl_prog_hash_size
+#define bpf_map_create_opts__last_field log_opts
LIBBPF_API int bpf_map_create(enum bpf_map_type map_type,
const char *map_name,
--
2.53.0
^ permalink raw reply related [flat|nested] 11+ messages in thread* [PATCH bpf-next v12 8/8] selftests/bpf: Add tests to verify map create failure log
2026-04-20 14:17 [PATCH bpf-next v12 0/8] bpf: Extend BPF syscall with common attributes support Leon Hwang
` (6 preceding siblings ...)
2026-04-20 14:18 ` [PATCH bpf-next v12 7/8] libbpf: " Leon Hwang
@ 2026-04-20 14:18 ` Leon Hwang
7 siblings, 0 replies; 11+ messages in thread
From: Leon Hwang @ 2026-04-20 14:18 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Daniel Borkmann, John Fastabend,
Andrii Nakryiko, Martin KaFai Lau, Eduard Zingerman, Song Liu,
Yonghong Song, KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa,
Shuah Khan, Christian Brauner, Seth Forshee, Yuichiro Tsuji,
Andrey Albershteyn, Leon Hwang, Willem de Bruijn, Jason Xing,
Tao Chen, Mykyta Yatsenko, Kumar Kartikeya Dwivedi,
Anton Protopopov, Amery Hung, Rong Tao, linux-kernel, linux-api,
linux-kselftest, kernel-patches-bot
Add tests to verify that the kernel reports the expected error messages
and correct log_true_size when map creation fails.
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
---
.../selftests/bpf/prog_tests/map_init.c | 166 ++++++++++++++++++
1 file changed, 166 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/map_init.c b/tools/testing/selftests/bpf/prog_tests/map_init.c
index 14a31109dd0e..5c61c8e37306 100644
--- a/tools/testing/selftests/bpf/prog_tests/map_init.c
+++ b/tools/testing/selftests/bpf/prog_tests/map_init.c
@@ -212,3 +212,169 @@ void test_map_init(void)
if (test__start_subtest("pcpu_lru_map_init"))
test_pcpu_lru_map_init();
}
+
+static void test_map_create(enum bpf_map_type map_type, const char *map_name,
+ struct bpf_map_create_opts *opts, const char *exp_msg)
+{
+ const int key_size = 4, value_size = 4, max_entries = 1;
+ char log_buf[128];
+ int fd;
+ LIBBPF_OPTS(bpf_log_opts, log_opts);
+
+ log_buf[0] = '\0';
+ log_opts.buf = log_buf;
+ log_opts.size = sizeof(log_buf);
+ log_opts.level = 1;
+ opts->log_opts = &log_opts;
+ fd = bpf_map_create(map_type, map_name, key_size, value_size, max_entries, opts);
+ if (!ASSERT_LT(fd, 0, "bpf_map_create")) {
+ close(fd);
+ return;
+ }
+
+ ASSERT_STREQ(log_buf, exp_msg, "log_buf");
+ ASSERT_EQ(log_opts.true_size, strlen(exp_msg) + 1, "true_size");
+}
+
+static void test_map_create_array(struct bpf_map_create_opts *opts, const char *exp_msg)
+{
+ test_map_create(BPF_MAP_TYPE_ARRAY, "test_map_create", opts, exp_msg);
+}
+
+static void test_invalid_vmlinux_value_type_id_struct_ops(void)
+{
+ const char *msg = "btf_vmlinux_value_type_id can only be used with struct_ops maps.\n";
+ LIBBPF_OPTS(bpf_map_create_opts, opts,
+ .btf_vmlinux_value_type_id = 1,
+ );
+
+ test_map_create_array(&opts, msg);
+}
+
+static void test_invalid_vmlinux_value_type_id_kv_type_id(void)
+{
+ const char *msg = "btf_vmlinux_value_type_id is mutually exclusive with btf_key_type_id and btf_value_type_id.\n";
+ LIBBPF_OPTS(bpf_map_create_opts, opts,
+ .btf_vmlinux_value_type_id = 1,
+ .btf_key_type_id = 1,
+ );
+
+ test_map_create(BPF_MAP_TYPE_STRUCT_OPS, "test_map_create", &opts, msg);
+}
+
+static void test_invalid_value_type_id(void)
+{
+ const char *msg = "Invalid btf_value_type_id.\n";
+ LIBBPF_OPTS(bpf_map_create_opts, opts,
+ .btf_key_type_id = 1,
+ );
+
+ test_map_create_array(&opts, msg);
+}
+
+static void test_invalid_map_extra(void)
+{
+ const char *msg = "Invalid map_extra.\n";
+ LIBBPF_OPTS(bpf_map_create_opts, opts,
+ .map_extra = 1,
+ );
+
+ test_map_create_array(&opts, msg);
+}
+
+static void test_invalid_numa_node(void)
+{
+ const char *msg = "Invalid numa_node.\n";
+ LIBBPF_OPTS(bpf_map_create_opts, opts,
+ .map_flags = BPF_F_NUMA_NODE,
+ .numa_node = 0xFF,
+ );
+
+ test_map_create_array(&opts, msg);
+}
+
+static void test_invalid_map_type(void)
+{
+ const char *msg = "Invalid map_type.\n";
+ LIBBPF_OPTS(bpf_map_create_opts, opts);
+
+ test_map_create(__MAX_BPF_MAP_TYPE, "test_map_create", &opts, msg);
+}
+
+static void test_invalid_token_fd(void)
+{
+ const char *msg = "Invalid map_token_fd.\n";
+ LIBBPF_OPTS(bpf_map_create_opts, opts,
+ .map_flags = BPF_F_TOKEN_FD,
+ .token_fd = 0xFF,
+ );
+
+ test_map_create_array(&opts, msg);
+}
+
+static void test_invalid_map_name(void)
+{
+ const char *msg = "Invalid map_name.\n";
+ LIBBPF_OPTS(bpf_map_create_opts, opts);
+
+ test_map_create(BPF_MAP_TYPE_ARRAY, "test-!@#", &opts, msg);
+}
+
+static void test_invalid_btf_fd(void)
+{
+ const char *msg = "Invalid btf_fd.\n";
+ LIBBPF_OPTS(bpf_map_create_opts, opts,
+ .btf_fd = -1,
+ .btf_key_type_id = 1,
+ .btf_value_type_id = 1,
+ );
+
+ test_map_create_array(&opts, msg);
+}
+
+static void test_excl_prog_hash_size_1(void)
+{
+ const char *msg = "Invalid excl_prog_hash_size.\n";
+ const char *hash = "DEADCODE";
+ LIBBPF_OPTS(bpf_map_create_opts, opts,
+ .excl_prog_hash = hash,
+ );
+
+ test_map_create_array(&opts, msg);
+}
+
+static void test_excl_prog_hash_size_2(void)
+{
+ const char *msg = "Invalid excl_prog_hash_size.\n";
+ LIBBPF_OPTS(bpf_map_create_opts, opts,
+ .excl_prog_hash_size = 1,
+ );
+
+ test_map_create_array(&opts, msg);
+}
+
+void test_map_create_failure(void)
+{
+ if (test__start_subtest("invalid_vmlinux_value_type_id_struct_ops"))
+ test_invalid_vmlinux_value_type_id_struct_ops();
+ if (test__start_subtest("invalid_vmlinux_value_type_id_kv_type_id"))
+ test_invalid_vmlinux_value_type_id_kv_type_id();
+ if (test__start_subtest("invalid_value_type_id"))
+ test_invalid_value_type_id();
+ if (test__start_subtest("invalid_map_extra"))
+ test_invalid_map_extra();
+ if (test__start_subtest("invalid_numa_node"))
+ test_invalid_numa_node();
+ if (test__start_subtest("invalid_map_type"))
+ test_invalid_map_type();
+ if (test__start_subtest("invalid_token_fd"))
+ test_invalid_token_fd();
+ if (test__start_subtest("invalid_map_name"))
+ test_invalid_map_name();
+ if (test__start_subtest("invalid_btf_fd"))
+ test_invalid_btf_fd();
+ if (test__start_subtest("invalid_excl_prog_hash_size_1"))
+ test_excl_prog_hash_size_1();
+ if (test__start_subtest("invalid_excl_prog_hash_size_2"))
+ test_excl_prog_hash_size_2();
+}
--
2.53.0
^ permalink raw reply related [flat|nested] 11+ messages in thread