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bpf: Add multi uprobe link 

Adding new multi uprobe link that allows to attach bpf program
to multiple uprobes.

Uprobes to attach are specified via new link_create uprobe_multi
union:

  struct {
    __aligned_u64   path;
    __aligned_u64   offsets;
    __aligned_u64   ref_ctr_offsets;
    __u32           cnt;
    __u32           flags;
  } uprobe_multi;

Uprobes are defined for single binary specified in path and multiple
calling sites specified in offsets array with optional reference
counters specified in ref_ctr_offsets array. All specified arrays
have length of 'cnt'.

The 'flags' supports single bit for now that marks the uprobe as
return probe.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230809083440.3209381-4-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Jiri Olsa 2023-08-09 10:34:15 +02:00 committed by Alexei Starovoitov
parent 3505cb9fa2
commit 89ae89f53d
5 changed files with 282 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
include/linux/trace_events.h
View File

@ -752,6 +752,7 @@ int bpf_get_perf_event_info(const struct perf_event *event, u32 *prog_id,
u32 *fd_type, const char **buf,
u64 *probe_offset, u64 *probe_addr);
int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog);
int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog);
#else
static inline unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx)
{
@ -798,6 +799,11 @@ bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
{
return -EOPNOTSUPP;
}
static inline int
bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
{
return -EOPNOTSUPP;
}
#endif
enum {

16
include/uapi/linux/bpf.h
View File

@ -1039,6 +1039,7 @@ enum bpf_attach_type {
BPF_NETFILTER,
BPF_TCX_INGRESS,
BPF_TCX_EGRESS,
BPF_TRACE_UPROBE_MULTI,
__MAX_BPF_ATTACH_TYPE
};
@ -1057,6 +1058,7 @@ enum bpf_link_type {
BPF_LINK_TYPE_STRUCT_OPS = 9,
BPF_LINK_TYPE_NETFILTER = 10,
BPF_LINK_TYPE_TCX = 11,
BPF_LINK_TYPE_UPROBE_MULTI = 12,
MAX_BPF_LINK_TYPE,
};
@ -1190,6 +1192,13 @@ enum {
BPF_F_KPROBE_MULTI_RETURN = (1U << 0)
};
/* link_create.uprobe_multi.flags used in LINK_CREATE command for
* BPF_TRACE_UPROBE_MULTI attach type to create return probe.
*/
enum {
BPF_F_UPROBE_MULTI_RETURN = (1U << 0)
};
/* link_create.netfilter.flags used in LINK_CREATE command for
* BPF_PROG_TYPE_NETFILTER to enable IP packet defragmentation.
*/
@ -1626,6 +1635,13 @@ union bpf_attr {
};
__u64 expected_revision;
} tcx;
struct {
__aligned_u64 path;
__aligned_u64 offsets;
__aligned_u64 ref_ctr_offsets;
__u32 cnt;
__u32 flags;
} uprobe_multi;
};
} link_create;

14
kernel/bpf/syscall.c
View File

@ -2815,10 +2815,12 @@ static void bpf_link_free_id(int id)
/* Clean up bpf_link and corresponding anon_inode file and FD. After
* anon_inode is created, bpf_link can't be just kfree()'d due to deferred
* anon_inode's release() call. This helper marksbpf_link as
* anon_inode's release() call. This helper marks bpf_link as
* defunct, releases anon_inode file and puts reserved FD. bpf_prog's refcnt
* is not decremented, it's the responsibility of a calling code that failed
* to complete bpf_link initialization.
* This helper eventually calls link's dealloc callback, but does not call
* link's release callback.
*/
void bpf_link_cleanup(struct bpf_link_primer *primer)
{
@ -3756,8 +3758,12 @@ static int bpf_prog_attach_check_attach_type(const struct bpf_prog *prog,
if (prog->expected_attach_type == BPF_TRACE_KPROBE_MULTI &&
attach_type != BPF_TRACE_KPROBE_MULTI)
return -EINVAL;
if (prog->expected_attach_type == BPF_TRACE_UPROBE_MULTI &&
attach_type != BPF_TRACE_UPROBE_MULTI)
return -EINVAL;
if (attach_type != BPF_PERF_EVENT &&
attach_type != BPF_TRACE_KPROBE_MULTI)
attach_type != BPF_TRACE_KPROBE_MULTI &&
attach_type != BPF_TRACE_UPROBE_MULTI)
return -EINVAL;
return 0;
case BPF_PROG_TYPE_SCHED_CLS:
@ -4953,8 +4959,10 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr)
case BPF_PROG_TYPE_KPROBE:
if (attr->link_create.attach_type == BPF_PERF_EVENT)
ret = bpf_perf_link_attach(attr, prog);
else
else if (attr->link_create.attach_type == BPF_TRACE_KPROBE_MULTI)
ret = bpf_kprobe_multi_link_attach(attr, prog);
else if (attr->link_create.attach_type == BPF_TRACE_UPROBE_MULTI)
ret = bpf_uprobe_multi_link_attach(attr, prog);
break;
default:
ret = -EINVAL;

233
kernel/trace/bpf_trace.c
View File

@ -23,6 +23,7 @@
#include <linux/sort.h>
#include <linux/key.h>
#include <linux/verification.h>
#include <linux/namei.h>
#include <net/bpf_sk_storage.h>
@ -2970,3 +2971,235 @@ static u64 bpf_kprobe_multi_entry_ip(struct bpf_run_ctx *ctx)
return 0;
}
#endif
#ifdef CONFIG_UPROBES
struct bpf_uprobe_multi_link;
struct bpf_uprobe {
struct bpf_uprobe_multi_link *link;
loff_t offset;
struct uprobe_consumer consumer;
};
struct bpf_uprobe_multi_link {
struct path path;
struct bpf_link link;
u32 cnt;
struct bpf_uprobe *uprobes;
};
struct bpf_uprobe_multi_run_ctx {
struct bpf_run_ctx run_ctx;
unsigned long entry_ip;
};
static void bpf_uprobe_unregister(struct path *path, struct bpf_uprobe *uprobes,
u32 cnt)
{
u32 i;
for (i = 0; i < cnt; i++) {
uprobe_unregister(d_real_inode(path->dentry), uprobes[i].offset,
&uprobes[i].consumer);
}
}
static void bpf_uprobe_multi_link_release(struct bpf_link *link)
{
struct bpf_uprobe_multi_link *umulti_link;
umulti_link = container_of(link, struct bpf_uprobe_multi_link, link);
bpf_uprobe_unregister(&umulti_link->path, umulti_link->uprobes, umulti_link->cnt);
}
static void bpf_uprobe_multi_link_dealloc(struct bpf_link *link)
{
struct bpf_uprobe_multi_link *umulti_link;
umulti_link = container_of(link, struct bpf_uprobe_multi_link, link);
path_put(&umulti_link->path);
kvfree(umulti_link->uprobes);
kfree(umulti_link);
}
static const struct bpf_link_ops bpf_uprobe_multi_link_lops = {
.release = bpf_uprobe_multi_link_release,
.dealloc = bpf_uprobe_multi_link_dealloc,
};
static int uprobe_prog_run(struct bpf_uprobe *uprobe,
unsigned long entry_ip,
struct pt_regs *regs)
{
struct bpf_uprobe_multi_link *link = uprobe->link;
struct bpf_uprobe_multi_run_ctx run_ctx = {
.entry_ip = entry_ip,
};
struct bpf_prog *prog = link->link.prog;
bool sleepable = prog->aux->sleepable;
struct bpf_run_ctx *old_run_ctx;
int err = 0;
if (sleepable)
rcu_read_lock_trace();
else
rcu_read_lock();
migrate_disable();
old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx);
err = bpf_prog_run(link->link.prog, regs);
bpf_reset_run_ctx(old_run_ctx);
migrate_enable();
if (sleepable)
rcu_read_unlock_trace();
else
rcu_read_unlock();
return err;
}
static int
uprobe_multi_link_handler(struct uprobe_consumer *con, struct pt_regs *regs)
{
struct bpf_uprobe *uprobe;
uprobe = container_of(con, struct bpf_uprobe, consumer);
return uprobe_prog_run(uprobe, instruction_pointer(regs), regs);
}
static int
uprobe_multi_link_ret_handler(struct uprobe_consumer *con, unsigned long func, struct pt_regs *regs)
{
struct bpf_uprobe *uprobe;
uprobe = container_of(con, struct bpf_uprobe, consumer);
return uprobe_prog_run(uprobe, func, regs);
}
int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
{
struct bpf_uprobe_multi_link *link = NULL;
unsigned long __user *uref_ctr_offsets;
unsigned long *ref_ctr_offsets = NULL;
struct bpf_link_primer link_primer;
struct bpf_uprobe *uprobes = NULL;
unsigned long __user *uoffsets;
void __user *upath;
u32 flags, cnt, i;
struct path path;
char *name;
int err;
/* no support for 32bit archs yet */
if (sizeof(u64) != sizeof(void *))
return -EOPNOTSUPP;
if (prog->expected_attach_type != BPF_TRACE_UPROBE_MULTI)
return -EINVAL;
flags = attr->link_create.uprobe_multi.flags;
if (flags & ~BPF_F_UPROBE_MULTI_RETURN)
return -EINVAL;
/*
* path, offsets and cnt are mandatory,
* ref_ctr_offsets is optional
*/
upath = u64_to_user_ptr(attr->link_create.uprobe_multi.path);
uoffsets = u64_to_user_ptr(attr->link_create.uprobe_multi.offsets);
cnt = attr->link_create.uprobe_multi.cnt;
if (!upath || !uoffsets || !cnt)
return -EINVAL;
uref_ctr_offsets = u64_to_user_ptr(attr->link_create.uprobe_multi.ref_ctr_offsets);
name = strndup_user(upath, PATH_MAX);
if (IS_ERR(name)) {
err = PTR_ERR(name);
return err;
}
err = kern_path(name, LOOKUP_FOLLOW, &path);
kfree(name);
if (err)
return err;
if (!d_is_reg(path.dentry)) {
err = -EBADF;
goto error_path_put;
}
err = -ENOMEM;
link = kzalloc(sizeof(*link), GFP_KERNEL);
uprobes = kvcalloc(cnt, sizeof(*uprobes), GFP_KERNEL);
if (!uprobes || !link)
goto error_free;
if (uref_ctr_offsets) {
ref_ctr_offsets = kvcalloc(cnt, sizeof(*ref_ctr_offsets), GFP_KERNEL);
if (!ref_ctr_offsets)
goto error_free;
}
for (i = 0; i < cnt; i++) {
if (uref_ctr_offsets && __get_user(ref_ctr_offsets[i], uref_ctr_offsets + i)) {
err = -EFAULT;
goto error_free;
}
if (__get_user(uprobes[i].offset, uoffsets + i)) {
err = -EFAULT;
goto error_free;
}
uprobes[i].link = link;
if (flags & BPF_F_UPROBE_MULTI_RETURN)
uprobes[i].consumer.ret_handler = uprobe_multi_link_ret_handler;
else
uprobes[i].consumer.handler = uprobe_multi_link_handler;
}
link->cnt = cnt;
link->uprobes = uprobes;
link->path = path;
bpf_link_init(&link->link, BPF_LINK_TYPE_UPROBE_MULTI,
&bpf_uprobe_multi_link_lops, prog);
for (i = 0; i < cnt; i++) {
err = uprobe_register_refctr(d_real_inode(link->path.dentry),
uprobes[i].offset,
ref_ctr_offsets ? ref_ctr_offsets[i] : 0,
&uprobes[i].consumer);
if (err) {
bpf_uprobe_unregister(&path, uprobes, i);
goto error_free;
}
}
err = bpf_link_prime(&link->link, &link_primer);
if (err)
goto error_free;
kvfree(ref_ctr_offsets);
return bpf_link_settle(&link_primer);
error_free:
kvfree(ref_ctr_offsets);
kvfree(uprobes);
kfree(link);
error_path_put:
path_put(&path);
return err;
}
#else /* !CONFIG_UPROBES */
int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
{
return -EOPNOTSUPP;
}
#endif /* CONFIG_UPROBES */

16
tools/include/uapi/linux/bpf.h
View File

@ -1039,6 +1039,7 @@ enum bpf_attach_type {
BPF_NETFILTER,
BPF_TCX_INGRESS,
BPF_TCX_EGRESS,
BPF_TRACE_UPROBE_MULTI,
__MAX_BPF_ATTACH_TYPE
};
@ -1057,6 +1058,7 @@ enum bpf_link_type {
BPF_LINK_TYPE_STRUCT_OPS = 9,
BPF_LINK_TYPE_NETFILTER = 10,
BPF_LINK_TYPE_TCX = 11,
BPF_LINK_TYPE_UPROBE_MULTI = 12,
MAX_BPF_LINK_TYPE,
};
@ -1190,6 +1192,13 @@ enum {
BPF_F_KPROBE_MULTI_RETURN = (1U << 0)
};
/* link_create.uprobe_multi.flags used in LINK_CREATE command for
* BPF_TRACE_UPROBE_MULTI attach type to create return probe.
*/
enum {
BPF_F_UPROBE_MULTI_RETURN = (1U << 0)
};
/* link_create.netfilter.flags used in LINK_CREATE command for
* BPF_PROG_TYPE_NETFILTER to enable IP packet defragmentation.
*/
@ -1626,6 +1635,13 @@ union bpf_attr {
};
__u64 expected_revision;
} tcx;
struct {
__aligned_u64 path;
__aligned_u64 offsets;
__aligned_u64 ref_ctr_offsets;
__u32 cnt;
__u32 flags;
} uprobe_multi;
};
} link_create;