Re: [PATCH v16 2/3] binder: report txn errors via generic netlink

Carlos Llamas
2025-03-11T04:13:03Z

On Mon, Mar 03, 2025 at 12:02:11PM -0800, Li Li wrote:
> From: Li Li <dualli@google.com>
>
> Introduce generic netlink messages into the binder driver so that the
> Linux/Android system administration processes can listen to important
> events and take corresponding actions, like stopping a broken app from
> attacking the OS by sending huge amount of spamming binder transactions.
>
> The binder netlink sources and headers are automatically generated from
> the corresponding binder netlink YAML spec. Don't modify them directly.
>
> Signed-off-by: Li Li <dualli@google.com>
> ---
> Documentation/admin-guide/binder_netlink.rst | 108 +++++++++
> Documentation/admin-guide/index.rst | 1 +
> Documentation/netlink/specs/binder.yaml | 116 ++++++++++
> drivers/android/Kconfig | 1 +
> drivers/android/Makefile | 2 +-
> drivers/android/binder.c | 229 ++++++++++++++++++-
> drivers/android/binder_internal.h | 16 ++
> drivers/android/binder_netlink.c | 46 ++++
> drivers/android/binder_netlink.h | 23 ++
> drivers/android/binder_trace.h | 35 +++
> include/uapi/linux/android/binder_netlink.h | 57 +++++
> 11 files changed, 630 insertions(+), 4 deletions(-)
> create mode 100644 Documentation/admin-guide/binder_netlink.rst
> create mode 100644 Documentation/netlink/specs/binder.yaml
> create mode 100644 drivers/android/binder_netlink.c
> create mode 100644 drivers/android/binder_netlink.h
> create mode 100644 include/uapi/linux/android/binder_netlink.h
>
> diff --git a/Documentation/admin-guide/binder_netlink.rst b/Documentation/admin-guide/binder_netlink.rst
> new file mode 100644
> index 000000000000..83f54f0d8c45
> --- /dev/null
> +++ b/Documentation/admin-guide/binder_netlink.rst
> @@ -0,0 +1,108 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +==============================================================
> +Generic Netlink for the Android Binder Driver (Binder Netlink)
> +==============================================================
> +
> +The Generic Netlink subsystem in the Linux kernel provides a generic way for
> +the Linux kernel to communicate with the user space applications via binder
> +driver. It is used to report binder transaction errors and warnings to user
> +space administration process. The driver allows multiple binder devices and
> +their corresponding binder contexts. Each context and their processes can be
> +configured independently to report their own transactions.
> +
> +Basically, the user space code uses the BINDER_CMD_REPORT_SETUP command to
> +request what kind of binder transactions should be reported by the driver.
> +The driver then echoes the attributes in a reply message to acknowledge the
> +request. The BINDER_CMD_REPORT_SETUP command also registers the current
> +user space process to receive the reports. This BINDER_CMD_REPORT_SETUP
> +command is protected by SELinux, to prevent unauthorized user apps from
> +triggering unexpected reports.
> +
> +Currently the driver reports these binder transaction errors and warnings.
> +1. "FAILED" transactions that fail to reach the target process;
> +2. "ASYNC_FROZEN" transactions that are delayed due to the target process
> +being frozen by cgroup freezer; or
> +3. "SPAM" transactions that are considered spamming according to existing
> +logic in binder_alloc.c.
> +
> +When the specified binder transactions happen, the driver uses the
> +BINDER_CMD_REPORT command to send a generic netlink message to the
> +registered process, containing the payload defined in binder.yaml.
> +
> +More details about the flags, attributes and operations can be found at the
> +the doc sections in Documentations/netlink/specs/binder.yaml and the
> +kernel-doc comments of the new source code in binder.{h|c}.
> +
> +Using Binder Netlink
> +--------------------
> +
> +The Binder Netlink can be used in the same way as any other generic netlink
> +drivers. Userspace application uses a raw netlink socket to send commands
> +to and receive packets from the kernel driver.
> +
> +Usage example (user space pseudo code):
> +
> +::
> + /*
> + * send() below is overloaded to pack netlink commands and attributes
> + * to nlattr/genlmsghdr/nlmsghdr and then send to the netlink socket.
> + *
> + * recv() below is overloaded to receive the raw netlink message from
> + * the netlink socket, parse nlmsghdr/genlmsghdr to find the netlink
> + * command and then return the nlattr payload.
> + */
> +
> + // open netlink socket
> + int fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_GENERIC);
> +
> + // bind netlink socket
> + bind(fd, struct socketaddr);
> +
> + // get the family id of the binder netlink
> + send(fd, CTRL_CMD_GETFAMILY, CTRL_ATTR_FAMILY_NAME,
> + BINDER_FAMILY_NAME);
> + void *data = recv(CTRL_CMD_NEWFAMILY);
> + if (!has_nla_type(data, CTRL_ATTR_FAMILY_ID)) {
> + // Binder Netlink isn't available on this version of Linux kernel
> + return;
> + }
> + __u16 id = nla(data)[CTRL_ATTR_FAMILY_ID];
> + __u32 grp = nla(data)[CTRL_ATTR_MCAST_GROUPS][CTRL_ATTR_MCAST_GRP_ID];
> +
> + // join the mcast group to listen to the binder netlink messages
> + setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &grp, sizeof(grp));
> +
> + // enable per-context binder report
> + send(fd, id, BINDER_CMD_REPORT_SETUP, "binder", 0,
> + BINDER_FLAG_FAILED | BINDER_FLAG_DELAYED);
> +
> + // confirm the per-context configuration
> + data = recv(fd, BINDER_CMD_REPLY);
> + char *context = nla(data)[BINDER_A_CMD_CONTEXT];
> + __u32 pid = nla(data)[BINDER_A_CMD_PID];
> + __u32 flags = nla(data)[BINDER_A_CMD_FLAGS];
> +
> + // set optional per-process report, overriding the per-context one
> + send(fd, id, BINDER_CMD_REPORT_SETUP, "binder", getpid(),
> + BINDER_FLAG_SPAM | BINDER_REPORT_OVERRIDE);
> +
> + // confirm the optional per-process configuration
> + data = recv(fd, BINDER_CMD_REPLY);
> + context = nla(data)[BINDER_A_CMD_CONTEXT];
> + pid = nla(data)[BINDER_A_CMD_PID];
> + flags = nla(data)[BINDER_A_CMD_FLAGS];
> +
> + // wait and read all binder reports
> + while (running) {
> + data = recv(fd, BINDER_CMD_REPORT);
> + auto *attr = nla(data)[BINDER_A_REPORT_XXX];
> +
> + // process binder report
> + do_something(*attr);
> + }
> +
> + // clean up
> + send(fd, id, BINDER_CMD_REPORT_SETUP, 0, 0);
> + send(fd, id, BINDER_CMD_REPORT_SETUP, getpid(), 0);
> + close(fd);
> diff --git a/Documentation/admin-guide/index.rst b/Documentation/admin-guide/index.rst
> index c8af32a8f800..655f39ddf1cf 100644
> --- a/Documentation/admin-guide/index.rst
> +++ b/Documentation/admin-guide/index.rst
> @@ -120,6 +120,7 @@ Block-layer and filesystem administration
> :maxdepth: 1
>
> bcache
> + binder_netlink
> binderfs
> blockdev/index
> cifs/index
> diff --git a/Documentation/netlink/specs/binder.yaml b/Documentation/netlink/specs/binder.yaml
> new file mode 100644
> index 000000000000..e184645f6c41
> --- /dev/null
> +++ b/Documentation/netlink/specs/binder.yaml
> @@ -0,0 +1,116 @@
> +# SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
> +
> +name: binder
> +protocol: genetlink
> +uapi-header: linux/android/binder_netlink.h
> +doc: Netlink protocol to report binder transaction errors and warnings.
> +
> +definitions:
> + -
> + type: flags
> + name: flag
> + doc: Define what kind of binder transactions should be reported.
> + entries: [ failed, async-frozen, spam, override ]
> +
> +attribute-sets:
> + -
> + name: cmd
> + doc: The supported attributes of "report-setup" command.
> + attributes:
> + -
> + name: context
> + type: string
> + doc: The binder context to enable binder netlink report.
> + -
> + name: pid
> + type: u32
> + doc: The binder proc to enable binder netlink report.
> + -
> + name: flags
> + type: u32
> + enum: flag
> + doc: What kind of binder transactions should be reported.
> + -
> + name: report
> + doc: The supported attributes of "report" command
> + attributes:
> + -
> + name: context
> + type: string
> + doc: The binder context where the binder netlink report happens.
> + -
> + name: err
> + type: u32
> + doc: Copy of binder_driver_return_protocol returned to the sender.
> + -
> + name: from_pid
> + type: u32
> + doc: Sender pid of the corresponding binder transaction.
> + -
> + name: from_tid
> + type: u32
> + doc: Sender tid of the corresponding binder transaction.
> + -
> + name: to_pid
> + type: u32
> + doc: Target pid of the corresponding binder transaction.
> + -
> + name: to_tid
> + type: u32
> + doc: Target tid of the corresponding binder transaction.
> + -
> + name: reply
> + type: u32
> + doc: 1 means the transaction is a reply, 0 otherwise.
> + -
> + name: flags
> + type: u32
> + doc: Copy of binder_transaction_data->flags.
> + -
> + name: code
> + type: u32
> + doc: Copy of binder_transaction_data->code.
> + -
> + name: data_size
> + type: u32
> + doc: Copy of binder_transaction_data->data_size.
> +
> +operations:
> + list:
> + -
> + name: report-setup
> + doc: Set flags from user space.
> + attribute-set: cmd
> +
> + do:
> + request: &params
> + attributes:
> + - context
> + - pid
> + - flags
> + reply: *params
> + -
> + name: report
> + doc: Send the requested reports to user space.
> + attribute-set: report
> +
> + event:
> + attributes:
> + - context
> + - err
> + - from_pid
> + - from_tid
> + - to_pid
> + - to_tid
> + - reply
> + - flags
> + - code
> + - data_size
> +
> +kernel-family:
> + headers: [ "binder_internal.h" ]
> +
> +mcast-groups:
> + list:
> + -
> + name: report
> diff --git a/drivers/android/Kconfig b/drivers/android/Kconfig
> index 07aa8ae0a058..e2fa620934e2 100644
> --- a/drivers/android/Kconfig
> +++ b/drivers/android/Kconfig
> @@ -4,6 +4,7 @@ menu "Android"
> config ANDROID_BINDER_IPC
> bool "Android Binder IPC Driver"
> depends on MMU
> + depends on NET
> default n
> help
> Binder is used in Android for both communication between processes,
> diff --git a/drivers/android/Makefile b/drivers/android/Makefile
> index c9d3d0c99c25..b8874dba884e 100644
> --- a/drivers/android/Makefile
> +++ b/drivers/android/Makefile
> @@ -2,5 +2,5 @@
> ccflags-y += -I$(src) # needed for trace events
>
> obj-$(CONFIG_ANDROID_BINDERFS) += binderfs.o
> -obj-$(CONFIG_ANDROID_BINDER_IPC) += binder.o binder_alloc.o
> +obj-$(CONFIG_ANDROID_BINDER_IPC) += binder.o binder_alloc.o binder_netlink.o
> obj-$(CONFIG_ANDROID_BINDER_IPC_SELFTEST) += binder_alloc_selftest.o
> diff --git a/drivers/android/binder.c b/drivers/android/binder.c
> index 76052006bd87..262c120a175a 100644
> --- a/drivers/android/binder.c
> +++ b/drivers/android/binder.c
> @@ -72,6 +72,7 @@
>
> #include <linux/cacheflush.h>
>
> +#include "binder_netlink.h"
> #include "binder_internal.h"
> #include "binder_trace.h"
>
> @@ -2990,6 +2991,110 @@ static void binder_set_txn_from_error(struct binder_transaction *t, int id,
> binder_thread_dec_tmpref(from);
> }
>
> +/**
> + * binder_find_proc() - find the binder_proc by pid
> + * @pid: the target process
> + *
> + * Returns the struct binder_proc if the pid is found, or NULL otherwise.
> + */
> +static struct binder_proc *binder_find_proc(int pid)
> +{
> + struct binder_proc *proc;
> +
> + mutex_lock(&binder_procs_lock);
> + hlist_for_each_entry(proc, &binder_procs, proc_node) {
> + if (proc->pid == pid)
> + break;

Wait... can't there be multiple binder_proc instances matching the same
pid? I know that binder_proc is a bit of a misnomer but what should you
do in such case? Shouldn't you set the flags in _all_ matching pids?

Furthermore, there could be a single task talking on multiple contexts,
so you could be returning the 'proc' that doesn't match the context that
you are looking for right?

> + }
> + mutex_unlock(&binder_procs_lock);
> +
> + return proc;
> +}
> +
> +/**
> + * binder_netlink_enabled() - check if binder netlink reports are enabled
> + * @proc: the binder_proc to check
> + * @mask: the categories of binder netlink reports
> + *
> + * Returns true if certain binder netlink reports are enabled for this binder
> + * proc (when per-process overriding takes effect) or context.
> + */
> +static bool binder_netlink_enabled(struct binder_proc *proc, u32 mask)
> +{
> + struct binder_context *context = proc->context;
> +
> + if (!genl_has_listeners(&binder_nl_family, &init_net, BINDER_NLGRP_REPORT))
> + return false;
> +
> + if (proc->report_flags & BINDER_FLAG_OVERRIDE)
> + return (proc->report_flags & mask) != 0;
> + else
> + return (context->report_flags & mask) != 0;
> +}
> +
> +/**
> + * binder_netlink_report() - report one binder netlink event
> + * @context: the binder context
> + * @err: copy of binder_driver_return_protocol returned to the sender
> + * @pid: sender process
> + * @tid: sender thread
> + * @to_pid: target process
> + * @to_tid: target thread
> + * @reply: whether the binder transaction is a reply
> + * @tr: the binder transaction data
> + *
> + * Packs the report data into a binder netlink message and send it.
> + */
> +static void binder_netlink_report(struct binder_context *context, u32 err,
> + u32 pid, u32 tid, u32 to_pid, u32 to_tid,

Instead of all these parameters, is there a way to pass the transaction
itself? Isn't this info already populated there? I think it even holds
the info you are looking for from the 'binder_transaction_data' below.

> + u32 reply,
> + struct binder_transaction_data *tr)
> +{
> + struct sk_buff *skb;
> + void *hdr;
> + int ret;
> +
> + trace_binder_netlink_report(context->name, err, pid, tid, to_pid,
> + to_tid, reply, tr);
> +
> + skb = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
> + if (!skb) {
> + pr_err("Failed to alloc binder netlink message\n");
> + return;
> + }
> +
> + hdr = genlmsg_put(skb, 0, atomic_inc_return(&context->report_seq),
> + &binder_nl_family, 0, BINDER_CMD_REPORT);
> + if (!hdr)
> + goto free_skb;
> +
> + if (nla_put_string(skb, BINDER_A_REPORT_CONTEXT, context->name) ||
> + nla_put_u32(skb, BINDER_A_REPORT_ERR, err) ||
> + nla_put_u32(skb, BINDER_A_REPORT_FROM_PID, pid) ||
> + nla_put_u32(skb, BINDER_A_REPORT_FROM_TID, tid) ||
> + nla_put_u32(skb, BINDER_A_REPORT_TO_PID, to_pid) ||
> + nla_put_u32(skb, BINDER_A_REPORT_TO_TID, to_tid) ||
> + nla_put_u32(skb, BINDER_A_REPORT_REPLY, reply) ||
> + nla_put_u32(skb, BINDER_A_REPORT_FLAGS, tr->flags) ||
> + nla_put_u32(skb, BINDER_A_REPORT_CODE, tr->code) ||
> + nla_put_u32(skb, BINDER_A_REPORT_DATA_SIZE, tr->data_size))
> + goto cancel_skb;
> +
> + genlmsg_end(skb, hdr);
> +
> + ret = genlmsg_multicast(&binder_nl_family, skb, 0, BINDER_NLGRP_REPORT, GFP_KERNEL);

Thanks for switching to multicast. On this topic, we can only have a
single global configuration at a time correct? e.g. context vs per-proc.
So all listeners would ahve to work with the same setup?

> + if (ret < 0)
> + pr_err("Failed to send binder netlink message: %d\n", ret);

nit: can you please add an emtpy new line before the return?

> + return;
> +
> +cancel_skb:
> + pr_err("Failed to add attributes to binder netlink message\n");
> + genlmsg_cancel(skb, hdr);
> +free_skb:
> + pr_err("Free binder netlink report message on error\n");
> + nlmsg_free(skb);
> +}
> +
> static void binder_transaction(struct binder_proc *proc,
> struct binder_thread *thread,
> struct binder_transaction_data *tr, int reply,
> @@ -3683,10 +3788,17 @@ static void binder_transaction(struct binder_proc *proc,
> return_error_line = __LINE__;
> goto err_copy_data_failed;
> }
> - if (t->buffer->oneway_spam_suspect)
> + if (t->buffer->oneway_spam_suspect) {
> tcomplete->type = BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT;
> - else
> + if (binder_netlink_enabled(proc, BINDER_FLAG_SPAM))
> + binder_netlink_report(context, BR_ONEWAY_SPAM_SUSPECT,
> + proc->pid, thread->pid,
> + target_proc ? target_proc->pid : 0,
> + target_thread ? target_thread->pid : 0,
> + reply, tr);
> + } else {
> tcomplete->type = BINDER_WORK_TRANSACTION_COMPLETE;
> + }
> t->work.type = BINDER_WORK_TRANSACTION;
>
> if (reply) {
> @@ -3736,8 +3848,15 @@ static void binder_transaction(struct binder_proc *proc,
> * process and is put in a pending queue, waiting for the target
> * process to be unfrozen.
> */
> - if (return_error == BR_TRANSACTION_PENDING_FROZEN)
> + if (return_error == BR_TRANSACTION_PENDING_FROZEN) {
> tcomplete->type = BINDER_WORK_TRANSACTION_PENDING;
> + if (binder_netlink_enabled(proc, BINDER_FLAG_ASYNC_FROZEN))
> + binder_netlink_report(context, return_error,
> + proc->pid, thread->pid,
> + target_proc ? target_proc->pid : 0,
> + target_thread ? target_thread->pid : 0,
> + reply, tr);
> + }
> binder_enqueue_thread_work(thread, tcomplete);
> if (return_error &&
> return_error != BR_TRANSACTION_PENDING_FROZEN)
> @@ -3799,6 +3918,13 @@ static void binder_transaction(struct binder_proc *proc,
> binder_dec_node_tmpref(target_node);
> }
>
> + if (binder_netlink_enabled(proc, BINDER_FLAG_FAILED))
> + binder_netlink_report(context, return_error,
> + proc->pid, thread->pid,
> + target_proc ? target_proc->pid : 0,
> + target_thread ? target_thread->pid : 0,
> + reply, tr);
> +
> binder_debug(BINDER_DEBUG_FAILED_TRANSACTION,
> "%d:%d transaction %s to %d:%d failed %d/%d/%d, code %u size %lld-%lld line %d\n",
> proc->pid, thread->pid, reply ? "reply" :
> @@ -6334,6 +6460,98 @@ binder_defer_work(struct binder_proc *proc, enum binder_deferred_state defer)
> mutex_unlock(&binder_deferred_lock);
> }
>
> +/**
> + * binder_nl_report_setup_doit() - netlink .doit handler
> + * @skb: the metadata struct passed from netlink driver
> + * @info: the generic netlink struct passed from netlink driver
> + *
> + * Implements the .doit function to process binder netlink commands.
> + */
> +int binder_nl_report_setup_doit(struct sk_buff *skb, struct genl_info *info)
> +{
> + struct binder_context *context = NULL;
> + struct binder_device *device;
> + struct binder_proc *proc;
> + u32 flags, pid;
> + void *hdr;
> + int ret;
> +
> + ret = security_binder_setup_report(current_cred());
> + if (ret < 0) {
> + NL_SET_ERR_MSG(info->extack, "Permission denied");
> + return ret;
> + }
> +
> + hlist_for_each_entry(device, &binder_devices, hlist) {
> + if (!nla_strcmp(info->attrs[BINDER_A_CMD_CONTEXT],
> + device->context.name)) {
> + context = &device->context;
> + break;
> + }
> + }
> +
> + if (!context) {
> + NL_SET_ERR_MSG(info->extack, "Unknown binder context");
> + return -EINVAL;
> + }
> +
> + pid = nla_get_u32(info->attrs[BINDER_A_CMD_PID]);
> + flags = nla_get_u32(info->attrs[BINDER_A_CMD_FLAGS]);
> +
> + if (!pid) {
> + /* Set the global flags for the whole binder context */
> + context->report_flags = flags;
> + } else {
> + /* Set the per-process flags */
> + proc = binder_find_proc(pid);
> + if (!proc) {
> + NL_SET_ERR_MSG_FMT(info->extack,
> + "Invalid binder report pid %u",
> + pid);
> + ret = -EINVAL;
> + goto err_exit;
> + }
> +
> + proc->report_flags = flags;
> + }
> +
> + skb = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
> + if (!skb) {
> + pr_err("Failed to alloc binder netlink reply message\n");
> + ret = -ENOMEM;
> + goto err_exit;
> + }
> +
> + hdr = genlmsg_iput(skb, info);
> + if (!hdr)
> + goto free_skb;
> +
> + if (nla_put_string(skb, BINDER_A_CMD_CONTEXT, context->name) ||
> + nla_put_u32(skb, BINDER_A_CMD_PID, pid) ||
> + nla_put_u32(skb, BINDER_A_CMD_FLAGS, flags))
> + goto cancel_skb;
> +
> + genlmsg_end(skb, hdr);
> +
> + if (genlmsg_reply(skb, info)) {
> + pr_err("Failed to send binder netlink reply message\n");
> + ret = -EFAULT;
> + goto err_exit;
> + }
> +
> + return 0;
> +
> +cancel_skb:
> + pr_err("Failed to add reply attributes to binder netlink message\n");
> + genlmsg_cancel(skb, hdr);
> +free_skb:
> + pr_err("Free binder netlink reply message on error\n");
> + nlmsg_free(skb);
> + ret = -EMSGSIZE;
> +err_exit:
> + return ret;
> +}
> +
> static void print_binder_transaction_ilocked(struct seq_file *m,
> struct binder_proc *proc,
> const char *prefix,
> @@ -7013,6 +7231,11 @@ static int __init binder_init(void)
> if (ret)
> goto err_init_binder_device_failed;
>
> + ret = genl_register_family(&binder_nl_family);
> + if (ret) {

You don't undo init_binderfs() here? If that seems hard, then you can
move up the genl registration instead, leaving init_binderfs() last.
However, you would need to then undo the genl_register_family() call I
suppose.

> + pr_err("Failed to register binder netlink family\n");
> + goto err_init_binder_device_failed;
> + }
> return ret;
>
> err_init_binder_device_failed:
> diff --git a/drivers/android/binder_internal.h b/drivers/android/binder_internal.h
> index 6a66c9769c6c..8ddd1ddea8e0 100644
> --- a/drivers/android/binder_internal.h
> +++ b/drivers/android/binder_internal.h
> @@ -11,15 +11,28 @@
> #include <linux/stddef.h>
> #include <linux/types.h>
> #include <linux/uidgid.h>
> +#include <net/genetlink.h>
> #include <uapi/linux/android/binderfs.h>
> #include "binder_alloc.h"
> #include "dbitmap.h"
>
> +/**
> + * struct binder_context - information about a binder domain
> + * @binder_context_mgr_node: the context manager
> + * @context_mgr_node_lock: the lock protecting the above context manager node
> + * @binder_context_mgr_uid: the uid of the above context manager
> + * @name: the name of the binder device
> + * @report_flags: the categories of binder transactions that would
> + * be reported (see enum binder_report_flag).
> + * @report_seq: the seq number of the generic netlink report
> + */
> struct binder_context {
> struct binder_node *binder_context_mgr_node;
> struct mutex context_mgr_node_lock;
> kuid_t binder_context_mgr_uid;
> const char *name;
> + u32 report_flags;
> + atomic_t report_seq;
> };
>
> /**
> @@ -413,6 +426,8 @@ struct binder_ref {
> * @binderfs_entry: process-specific binderfs log file
> * @oneway_spam_detection_enabled: process enabled oneway spam detection
> * or not
> + * @report_flags: the categories of binder transactions that would
> + * be reported (see enum binder_genl_flag).
> *
> * Bookkeeping structure for binder processes
> */
> @@ -451,6 +466,7 @@ struct binder_proc {
> spinlock_t outer_lock;
> struct dentry *binderfs_entry;
> bool oneway_spam_detection_enabled;
> + u32 report_flags;
> };
>
> /**
> diff --git a/drivers/android/binder_netlink.c b/drivers/android/binder_netlink.c
> new file mode 100644
> index 000000000000..9dc1820951c3
> --- /dev/null
> +++ b/drivers/android/binder_netlink.c
> @@ -0,0 +1,46 @@
> +// SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
> +/* Do not edit directly, auto-generated from: */
> +/* Documentation/netlink/specs/binder.yaml */
> +/* YNL-GEN kernel source */
> +
> +#include <net/netlink.h>
> +#include <net/genetlink.h>
> +
> +#include "binder_netlink.h"
> +
> +#include <uapi/linux/android/binder_netlink.h>
> +#include <binder_internal.h>
> +
> +/* BINDER_CMD_REPORT_SETUP - do */
> +static const struct nla_policy binder_report_setup_nl_policy[BINDER_A_CMD_FLAGS + 1] = {
> + [BINDER_A_CMD_CONTEXT] = { .type = NLA_NUL_STRING, },
> + [BINDER_A_CMD_PID] = { .type = NLA_U32, },
> + [BINDER_A_CMD_FLAGS] = NLA_POLICY_MASK(NLA_U32, 0xf),
> +};
> +
> +/* Ops table for binder */
> +static const struct genl_split_ops binder_nl_ops[] = {
> + {
> + .cmd = BINDER_CMD_REPORT_SETUP,
> + .doit = binder_nl_report_setup_doit,
> + .policy = binder_report_setup_nl_policy,
> + .maxattr = BINDER_A_CMD_FLAGS,
> + .flags = GENL_CMD_CAP_DO,
> + },
> +};
> +
> +static const struct genl_multicast_group binder_nl_mcgrps[] = {
> + [BINDER_NLGRP_REPORT] = { "report", },
> +};
> +
> +struct genl_family binder_nl_family __ro_after_init = {
> + .name = BINDER_FAMILY_NAME,
> + .version = BINDER_FAMILY_VERSION,
> + .netnsok = true,
> + .parallel_ops = true,
> + .module = THIS_MODULE,
> + .split_ops = binder_nl_ops,
> + .n_split_ops = ARRAY_SIZE(binder_nl_ops),
> + .mcgrps = binder_nl_mcgrps,
> + .n_mcgrps = ARRAY_SIZE(binder_nl_mcgrps),
> +};
> diff --git a/drivers/android/binder_netlink.h b/drivers/android/binder_netlink.h
> new file mode 100644
> index 000000000000..0ef8c91ab319
> --- /dev/null
> +++ b/drivers/android/binder_netlink.h
> @@ -0,0 +1,23 @@
> +/* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) */
> +/* Do not edit directly, auto-generated from: */
> +/* Documentation/netlink/specs/binder.yaml */
> +/* YNL-GEN kernel header */
> +
> +#ifndef _LINUX_BINDER_GEN_H
> +#define _LINUX_BINDER_GEN_H
> +
> +#include <net/netlink.h>
> +#include <net/genetlink.h>
> +
> +#include <uapi/linux/android/binder_netlink.h>
> +#include <binder_internal.h>
> +
> +int binder_nl_report_setup_doit(struct sk_buff *skb, struct genl_info *info);
> +
> +enum {
> + BINDER_NLGRP_REPORT,
> +};
> +
> +extern struct genl_family binder_nl_family;
> +
> +#endif /* _LINUX_BINDER_GEN_H */
> diff --git a/drivers/android/binder_trace.h b/drivers/android/binder_trace.h
> index 16de1b9e72f7..6fb454bcd857 100644
> --- a/drivers/android/binder_trace.h
> +++ b/drivers/android/binder_trace.h
> @@ -423,6 +423,41 @@ TRACE_EVENT(binder_return,
> "unknown")
> );
>
> +TRACE_EVENT(binder_netlink_report,
> + TP_PROTO(const char *name, u32 err, u32 pid, u32 tid, u32 to_pid,
> + u32 to_tid, u32 reply, struct binder_transaction_data *tr),

Similarly here I think you could get away with passing 'struct
binder_transaction' instead of all the individual fields.

> + TP_ARGS(name, err, pid, tid, to_pid, to_tid, reply, tr),
> + TP_STRUCT__entry(
> + __field(const char *, name)
> + __field(u32, err)
> + __field(u32, pid)
> + __field(u32, tid)
> + __field(u32, to_pid)
> + __field(u32, to_tid)
> + __field(u32, reply)
> + __field(u32, flags)
> + __field(u32, code)
> + __field(binder_size_t, data_size)
> + ),
> + TP_fast_assign(
> + __entry->name = name;
> + __entry->err = err;
> + __entry->pid = pid;
> + __entry->tid = tid;
> + __entry->to_pid = to_pid;
> + __entry->to_tid = to_tid;
> + __entry->reply = reply;
> + __entry->flags = tr->flags;
> + __entry->code = tr->code;
> + __entry->data_size = tr->data_size;
> + ),
> + TP_printk("%s: %d %d:%d -> %d:%d %s flags=0x08%x code=%d %llu",
> + __entry->name, __entry->err, __entry->pid, __entry->tid,
> + __entry->to_pid, __entry->to_tid,
> + __entry->reply ? "reply" : "",
> + __entry->flags, __entry->code, __entry->data_size)
> +);
> +
> #endif /* _BINDER_TRACE_H */
>
> #undef TRACE_INCLUDE_PATH
> diff --git a/include/uapi/linux/android/binder_netlink.h b/include/uapi/linux/android/binder_netlink.h
> new file mode 100644
> index 000000000000..fa926ed19507
> --- /dev/null
> +++ b/include/uapi/linux/android/binder_netlink.h
> @@ -0,0 +1,57 @@
> +/* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) */
> +/* Do not edit directly, auto-generated from: */
> +/* Documentation/netlink/specs/binder.yaml */
> +/* YNL-GEN uapi header */
> +
> +#ifndef _UAPI_LINUX_ANDROID_BINDER_NETLINK_H
> +#define _UAPI_LINUX_ANDROID_BINDER_NETLINK_H
> +
> +#define BINDER_FAMILY_NAME "binder"
> +#define BINDER_FAMILY_VERSION 1
> +
> +/*
> + * Define what kind of binder transactions should be reported.
> + */
> +enum binder_flag {
> + BINDER_FLAG_FAILED = 1,
> + BINDER_FLAG_ASYNC_FROZEN = 2,
> + BINDER_FLAG_SPAM = 4,
> + BINDER_FLAG_OVERRIDE = 8,
> +};
> +
> +enum {
> + BINDER_A_CMD_CONTEXT = 1,
> + BINDER_A_CMD_PID,
> + BINDER_A_CMD_FLAGS,
> +
> + __BINDER_A_CMD_MAX,
> + BINDER_A_CMD_MAX = (__BINDER_A_CMD_MAX - 1)
> +};
> +
> +enum {
> + BINDER_A_REPORT_CONTEXT = 1,
> + BINDER_A_REPORT_ERR,
> + BINDER_A_REPORT_FROM_PID,
> + BINDER_A_REPORT_FROM_TID,
> + BINDER_A_REPORT_TO_PID,
> + BINDER_A_REPORT_TO_TID,
> + BINDER_A_REPORT_REPLY,
> + BINDER_A_REPORT_FLAGS,
> + BINDER_A_REPORT_CODE,
> + BINDER_A_REPORT_DATA_SIZE,
> +
> + __BINDER_A_REPORT_MAX,
> + BINDER_A_REPORT_MAX = (__BINDER_A_REPORT_MAX - 1)
> +};
> +
> +enum {
> + BINDER_CMD_REPORT_SETUP = 1,
> + BINDER_CMD_REPORT,
> +
> + __BINDER_CMD_MAX,
> + BINDER_CMD_MAX = (__BINDER_CMD_MAX - 1)
> +};
> +
> +#define BINDER_MCGRP_REPORT "report"
> +
> +#endif /* _UAPI_LINUX_ANDROID_BINDER_NETLINK_H */
> --
> 2.48.1.711.g2feabab25a-goog
>