Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 275 insertions, 0 deletions

diff --git a/io_uring/bpf-ops.c b/io_uring/bpf-ops.c
new file mode 100644
index 000000000..cf2bd068e
--- /dev/null
+++ b/io_uring/bpf-ops.c
@@ -0,0 +1,275 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/mutex.h>
+#include <linux/bpf.h>
+#include <linux/bpf_verifier.h>
+
+#include "io_uring.h"
+#include "register.h"
+#include "loop.h"
+#include "memmap.h"
+#include "bpf-ops.h"
+
+static DEFINE_MUTEX(io_bpf_ctrl_mutex);
+static const struct btf_type *loop_params_type;
+
+__bpf_kfunc_start_defs();
+
+__bpf_kfunc int bpf_io_uring_submit_sqes(struct iou_ctx *loop_ctx, u32 nr)
+{
+	struct io_ring_ctx *ctx = io_loop_demangle_ctx(loop_ctx);
+
+	return io_submit_sqes(ctx, nr);
+}
+
+__bpf_kfunc
+__u8 *bpf_io_uring_get_region(struct iou_ctx *loop_ctx, __u32 region_id,
+			      const size_t rdwr_buf_size)
+{
+	struct io_ring_ctx *ctx = io_loop_demangle_ctx(loop_ctx);
+	struct io_mapped_region *r;
+
+	lockdep_assert_held(&ctx->uring_lock);
+
+	switch (region_id) {
+	case IOU_REGION_MEM:
+		r = &ctx->param_region;
+		break;
+	case IOU_REGION_CQ:
+		r = &ctx->ring_region;
+		break;
+	case IOU_REGION_SQ:
+		r = &ctx->sq_region;
+		break;
+	default:
+		return NULL;
+	}
+
+	if (unlikely(rdwr_buf_size > io_region_size(r)))
+		return NULL;
+	return io_region_get_ptr(r);
+}
+
+__bpf_kfunc_end_defs();
+
+BTF_KFUNCS_START(io_uring_kfunc_set)
+BTF_ID_FLAGS(func, bpf_io_uring_submit_sqes, KF_SLEEPABLE);
+BTF_ID_FLAGS(func, bpf_io_uring_get_region, KF_RET_NULL);
+BTF_KFUNCS_END(io_uring_kfunc_set)
+
+static const struct btf_kfunc_id_set bpf_io_uring_kfunc_set = {
+	.owner = THIS_MODULE,
+	.set = &io_uring_kfunc_set,
+};
+
+static int io_bpf_ops__loop_step(struct iou_ctx *ctx,
+				 struct iou_loop_params *lp)
+{
+	return IOU_LOOP_STOP;
+}
+
+static struct io_uring_bpf_ops io_bpf_ops_stubs = {
+	.loop_step = io_bpf_ops__loop_step,
+};
+
+static bool bpf_io_is_valid_access(int off, int size,
+				    enum bpf_access_type type,
+				    const struct bpf_prog *prog,
+				    struct bpf_insn_access_aux *info)
+{
+	if (type != BPF_READ)
+		return false;
+	if (off < 0 || off >= sizeof(__u64) * MAX_BPF_FUNC_ARGS)
+		return false;
+	if (off % size != 0)
+		return false;
+
+	return btf_ctx_access(off, size, type, prog, info);
+}
+
+static int bpf_io_btf_struct_access(struct bpf_verifier_log *log,
+				    const struct bpf_reg_state *reg, int off,
+				    int size)
+{
+	const struct btf_type *t = btf_type_by_id(reg->btf, reg->btf_id);
+
+	if (t == loop_params_type) {
+		if (off + size <= offsetofend(struct iou_loop_params, cq_wait_idx))
+			return SCALAR_VALUE;
+	}
+
+	return -EACCES;
+}
+
+static const struct bpf_verifier_ops bpf_io_verifier_ops = {
+	.get_func_proto = bpf_base_func_proto,
+	.is_valid_access = bpf_io_is_valid_access,
+	.btf_struct_access = bpf_io_btf_struct_access,
+};
+
+static const struct btf_type *
+io_lookup_struct_type(struct btf *btf, const char *name)
+{
+	s32 type_id;
+
+	type_id = btf_find_by_name_kind(btf, name, BTF_KIND_STRUCT);
+	if (type_id < 0)
+		return NULL;
+	return btf_type_by_id(btf, type_id);
+}
+
+static int bpf_io_init(struct btf *btf)
+{
+	int ret;
+
+	loop_params_type = io_lookup_struct_type(btf, "iou_loop_params");
+	if (!loop_params_type) {
+		pr_err("io_uring: Failed to locate iou_loop_params\n");
+		return -EINVAL;
+	}
+
+	ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS,
+					&bpf_io_uring_kfunc_set);
+	if (ret) {
+		pr_err("io_uring: Failed to register kfuncs (%d)\n", ret);
+		return ret;
+	}
+	return 0;
+}
+
+static int bpf_io_check_member(const struct btf_type *t,
+				const struct btf_member *member,
+				const struct bpf_prog *prog)
+{
+	return 0;
+}
+
+static int bpf_io_init_member(const struct btf_type *t,
+			       const struct btf_member *member,
+			       void *kdata, const void *udata)
+{
+	u32 moff = __btf_member_bit_offset(t, member) / 8;
+	const struct io_uring_bpf_ops *uops = udata;
+	struct io_uring_bpf_ops *ops = kdata;
+
+	switch (moff) {
+	case offsetof(struct io_uring_bpf_ops, ring_fd):
+		ops->ring_fd = uops->ring_fd;
+		return 1;
+	}
+	return 0;
+}
+
+static int io_install_bpf(struct io_ring_ctx *ctx, struct io_uring_bpf_ops *ops)
+{
+	if (ctx->flags & (IORING_SETUP_SQPOLL | IORING_SETUP_IOPOLL))
+		return -EOPNOTSUPP;
+	if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN))
+		return -EOPNOTSUPP;
+
+	if (ctx->bpf_ops)
+		return -EBUSY;
+	if (ops->priv)
+		return -EBUSY;
+	if (WARN_ON_ONCE(!ops->loop_step))
+		return -EINVAL;
+
+	ops->priv = ctx;
+	ctx->bpf_ops = ops;
+	ctx->loop_step = ops->loop_step;
+	return 0;
+}
+
+static int bpf_io_reg(void *kdata, struct bpf_link *link)
+{
+	struct io_uring_bpf_ops *ops = kdata;
+	struct io_ring_ctx *ctx;
+	struct file *file;
+	int ret = -EBUSY;
+
+	file = io_uring_ctx_get_file(ops->ring_fd, false);
+	if (IS_ERR(file))
+		return PTR_ERR(file);
+	ctx = file->private_data;
+
+	scoped_guard(mutex, &io_bpf_ctrl_mutex) {
+		guard(mutex)(&ctx->uring_lock);
+		ret = io_install_bpf(ctx, ops);
+	}
+
+	fput(file);
+	return ret;
+}
+
+static void io_eject_bpf(struct io_ring_ctx *ctx)
+{
+	struct io_uring_bpf_ops *ops = ctx->bpf_ops;
+
+	if (WARN_ON_ONCE(!ops))
+		return;
+	if (WARN_ON_ONCE(ops->priv != ctx))
+		return;
+
+	ops->priv = NULL;
+	ctx->bpf_ops = NULL;
+	ctx->loop_step = NULL;
+}
+
+static void bpf_io_unreg(void *kdata, struct bpf_link *link)
+{
+	struct io_uring_bpf_ops *ops = kdata;
+	struct io_ring_ctx *ctx;
+
+	guard(mutex)(&io_bpf_ctrl_mutex);
+	ctx = ops->priv;
+	if (ctx) {
+		guard(mutex)(&ctx->uring_lock);
+		if (WARN_ON_ONCE(ctx->bpf_ops != ops))
+			return;
+
+		io_eject_bpf(ctx);
+	}
+}
+
+void io_unregister_bpf_ops(struct io_ring_ctx *ctx)
+{
+	/*
+	 * ->bpf_ops is write protected by io_bpf_ctrl_mutex and uring_lock,
+	 * and read protected by either. Try to avoid taking the global lock
+	 * for rings that never had any bpf installed.
+	 */
+	scoped_guard(mutex, &ctx->uring_lock) {
+		if (!ctx->bpf_ops)
+			return;
+	}
+
+	guard(mutex)(&io_bpf_ctrl_mutex);
+	guard(mutex)(&ctx->uring_lock);
+	if (ctx->bpf_ops)
+		io_eject_bpf(ctx);
+}
+
+static struct bpf_struct_ops bpf_ring_ops = {
+	.verifier_ops = &bpf_io_verifier_ops,
+	.reg = bpf_io_reg,
+	.unreg = bpf_io_unreg,
+	.check_member = bpf_io_check_member,
+	.init_member = bpf_io_init_member,
+	.init = bpf_io_init,
+	.cfi_stubs = &io_bpf_ops_stubs,
+	.name = "io_uring_bpf_ops",
+	.owner = THIS_MODULE,
+};
+
+static int __init io_uring_bpf_init(void)
+{
+	int ret;
+
+	ret = register_bpf_struct_ops(&bpf_ring_ops, io_uring_bpf_ops);
+	if (ret) {
+		pr_err("io_uring: Failed to register struct_ops (%d)\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+__initcall(io_uring_bpf_init);