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@xxxxxxxxxx>
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
include/linux/trace_events.h | 6 +
include/uapi/linux/bpf.h | 16 +++
kernel/bpf/syscall.c | 14 +-
kernel/trace/bpf_trace.c | 237 +++++++++++++++++++++++++++++++++
tools/include/uapi/linux/bpf.h | 16 +++
5 files changed, 286 insertions(+), 3 deletions(-)
diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index e66d04dbe56a..5b85cf18c350 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -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 {
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 7abb382dc6c1..f112a0b948f3 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -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;
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 7c01186d4078..75c83300339e 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -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)
{
@@ -3757,8 +3759,12 @@ 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:
@@ -4954,8 +4960,10 @@ 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;
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index c92eb8c6ff08..10284fd46f98 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -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>
@@ -2965,3 +2966,239 @@ 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;
+
+ might_fault();
+
+ migrate_disable();
+
+ if (sleepable)
+ rcu_read_lock_trace();
+ else
+ rcu_read_lock();
+
+ 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);
+
+ if (sleepable)
+ rcu_read_unlock_trace();
+ else
+ rcu_read_unlock();
+
+ migrate_enable();
+ 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);
+
+ err = bpf_link_prime(&link->link, &link_primer);
+ if (err)
+ goto error_free;
+
+ 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);
+ bpf_link_cleanup(&link_primer);
+ kvfree(ref_ctr_offsets);
+ return err;
+ }
+ }
+
+ 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 */
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 7abb382dc6c1..f112a0b948f3 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -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;
--
2.41.0
