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, 185 insertions, 0 deletions

diff --git a/arch/powerpc/boot/libfdt-wrapper.c b/arch/powerpc/boot/libfdt-wrapper.c
new file mode 100644
index 000000000..217d0d7a6
--- /dev/null
+++ b/arch/powerpc/boot/libfdt-wrapper.c
@@ -0,0 +1,185 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * This file does the necessary interface mapping between the bootwrapper
+ * device tree operations and the interface provided by shared source
+ * files flatdevicetree.[ch].
+ *
+ * Copyright 2007 David Gibson, IBM Corporation.
+ */
+
+#include <stddef.h>
+#include <stdio.h>
+#include <page.h>
+#include <libfdt.h>
+#include "ops.h"
+
+#define DEBUG	0
+#define BAD_ERROR(err)	(((err) < 0) \
+			 && ((err) != -FDT_ERR_NOTFOUND) \
+			 && ((err) != -FDT_ERR_EXISTS))
+
+#define check_err(err) \
+	({ \
+		if (BAD_ERROR(err) || ((err < 0) && DEBUG)) \
+			printf("%s():%d  %s\n\r", __func__, __LINE__, \
+			       fdt_strerror(err)); \
+		if (BAD_ERROR(err)) \
+			exit(); \
+		(err < 0) ? -1 : 0; \
+	})
+
+#define offset_devp(off)	\
+	({ \
+		unsigned long _offset = (off); \
+		check_err(_offset) ? NULL : (void *)(_offset+1); \
+	})
+
+#define devp_offset_find(devp)	(((unsigned long)(devp))-1)
+#define devp_offset(devp)	(devp ? ((unsigned long)(devp))-1 : 0)
+
+static void *fdt;
+static void *buf; /* = NULL */
+
+#define EXPAND_GRANULARITY	1024
+
+static void expand_buf(int minexpand)
+{
+	int size = fdt_totalsize(fdt);
+	int rc;
+
+	size = _ALIGN(size + minexpand, EXPAND_GRANULARITY);
+	buf = platform_ops.realloc(buf, size);
+	if (!buf)
+		fatal("Couldn't find %d bytes to expand device tree\n\r", size);
+	rc = fdt_open_into(fdt, buf, size);
+	if (rc != 0)
+		fatal("Couldn't expand fdt into new buffer: %s\n\r",
+		      fdt_strerror(rc));
+
+	fdt = buf;
+}
+
+static void *fdt_wrapper_finddevice(const char *path)
+{
+	return offset_devp(fdt_path_offset(fdt, path));
+}
+
+static int fdt_wrapper_getprop(const void *devp, const char *name,
+			       void *buf, const int buflen)
+{
+	const void *p;
+	int len;
+
+	p = fdt_getprop(fdt, devp_offset(devp), name, &len);
+	if (!p)
+		return check_err(len);
+	memcpy(buf, p, min(len, buflen));
+	return len;
+}
+
+static int fdt_wrapper_setprop(const void *devp, const char *name,
+			       const void *buf, const int len)
+{
+	int rc;
+
+	rc = fdt_setprop(fdt, devp_offset(devp), name, buf, len);
+	if (rc == -FDT_ERR_NOSPACE) {
+		expand_buf(len + 16);
+		rc = fdt_setprop(fdt, devp_offset(devp), name, buf, len);
+	}
+
+	return check_err(rc);
+}
+
+static int fdt_wrapper_del_node(const void *devp)
+{
+	return fdt_del_node(fdt, devp_offset(devp));
+}
+
+static void *fdt_wrapper_get_parent(const void *devp)
+{
+	return offset_devp(fdt_parent_offset(fdt, devp_offset(devp)));
+}
+
+static void *fdt_wrapper_create_node(const void *devp, const char *name)
+{
+	int offset;
+
+	offset = fdt_add_subnode(fdt, devp_offset(devp), name);
+	if (offset == -FDT_ERR_NOSPACE) {
+		expand_buf(strlen(name) + 16);
+		offset = fdt_add_subnode(fdt, devp_offset(devp), name);
+	}
+
+	return offset_devp(offset);
+}
+
+static void *fdt_wrapper_find_node_by_prop_value(const void *prev,
+						 const char *name,
+						 const char *val,
+						 int len)
+{
+	int offset = fdt_node_offset_by_prop_value(fdt, devp_offset_find(prev),
+	                                           name, val, len);
+	return offset_devp(offset);
+}
+
+static void *fdt_wrapper_find_node_by_compatible(const void *prev,
+						 const char *val)
+{
+	int offset = fdt_node_offset_by_compatible(fdt, devp_offset_find(prev),
+	                                           val);
+	return offset_devp(offset);
+}
+
+static char *fdt_wrapper_get_path(const void *devp, char *buf, int len)
+{
+	int rc;
+
+	rc = fdt_get_path(fdt, devp_offset(devp), buf, len);
+	if (check_err(rc))
+		return NULL;
+	return buf;
+}
+
+static unsigned long fdt_wrapper_finalize(void)
+{
+	int rc;
+
+	rc = fdt_pack(fdt);
+	if (rc != 0)
+		fatal("Couldn't pack flat tree: %s\n\r",
+		      fdt_strerror(rc));
+	return (unsigned long)fdt;
+}
+
+void fdt_init(void *blob)
+{
+	int err;
+	int bufsize;
+
+	dt_ops.finddevice = fdt_wrapper_finddevice;
+	dt_ops.getprop = fdt_wrapper_getprop;
+	dt_ops.setprop = fdt_wrapper_setprop;
+	dt_ops.get_parent = fdt_wrapper_get_parent;
+	dt_ops.create_node = fdt_wrapper_create_node;
+	dt_ops.find_node_by_prop_value = fdt_wrapper_find_node_by_prop_value;
+	dt_ops.find_node_by_compatible = fdt_wrapper_find_node_by_compatible;
+	dt_ops.del_node = fdt_wrapper_del_node;
+	dt_ops.get_path = fdt_wrapper_get_path;
+	dt_ops.finalize = fdt_wrapper_finalize;
+
+	/* Make sure the dt blob is the right version and so forth */
+	fdt = blob;
+	bufsize = fdt_totalsize(fdt) + EXPAND_GRANULARITY;
+	buf = malloc(bufsize);
+	if(!buf)
+		fatal("malloc failed. can't relocate the device tree\n\r");
+
+	err = fdt_open_into(fdt, buf, bufsize);
+
+	if (err != 0)
+		fatal("fdt_init(): %s\n\r", fdt_strerror(err));
+
+	fdt = buf;
+}