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, 383 insertions, 0 deletions

diff --git a/tools/perf/tests/vmlinux-kallsyms.c b/tools/perf/tests/vmlinux-kallsyms.c
new file mode 100644
index 000000000..9396c8a77
--- /dev/null
+++ b/tools/perf/tests/vmlinux-kallsyms.c
@@ -0,0 +1,383 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/compiler.h>
+#include <linux/rbtree.h>
+#include <inttypes.h>
+#include <string.h>
+#include <ctype.h>
+#include <stdlib.h>
+#include "dso.h"
+#include "map.h"
+#include "symbol.h"
+#include <internal/lib.h> // page_size
+#include "tests.h"
+#include "debug.h"
+#include "machine.h"
+
+#define UM(x) map__unmap_ip(kallsyms_map, (x))
+
+static bool is_ignored_symbol(const char *name, char type)
+{
+	/* Symbol names that exactly match to the following are ignored.*/
+	static const char * const ignored_symbols[] = {
+		/*
+		 * Symbols which vary between passes. Passes 1 and 2 must have
+		 * identical symbol lists. The kallsyms_* symbols below are
+		 * only added after pass 1, they would be included in pass 2
+		 * when --all-symbols is specified so exclude them to get a
+		 * stable symbol list.
+		 */
+		"kallsyms_offsets",
+		"kallsyms_num_syms",
+		"kallsyms_names",
+		"kallsyms_markers",
+		"kallsyms_token_table",
+		"kallsyms_token_index",
+		/* Exclude linker generated symbols which vary between passes */
+		"_SDA_BASE_",		/* ppc */
+		"_SDA2_BASE_",		/* ppc */
+		NULL
+	};
+
+	/* Symbol names that begin with the following are ignored.*/
+	static const char * const ignored_prefixes[] = {
+		"$",			/* local symbols for ARM, MIPS, etc. */
+		".L",			/* local labels, .LBB,.Ltmpxxx,.L__unnamed_xx,.LASANPC, etc. */
+		"__crc_",		/* modversions */
+		"__efistub_",		/* arm64 EFI stub namespace */
+		"__kvm_nvhe_$",		/* arm64 local symbols in non-VHE KVM namespace */
+		"__kvm_nvhe_.L",	/* arm64 local symbols in non-VHE KVM namespace */
+		"__AArch64ADRPThunk_",	/* arm64 lld */
+		"__ARMV5PILongThunk_",	/* arm lld */
+		"__ARMV7PILongThunk_",
+		"__ThumbV7PILongThunk_",
+		"__LA25Thunk_",		/* mips lld */
+		"__microLA25Thunk_",
+		NULL
+	};
+
+	/* Symbol names that end with the following are ignored.*/
+	static const char * const ignored_suffixes[] = {
+		"_from_arm",		/* arm */
+		"_from_thumb",		/* arm */
+		"_veneer",		/* arm */
+		NULL
+	};
+
+	/* Symbol names that contain the following are ignored.*/
+	static const char * const ignored_matches[] = {
+		".long_branch.",	/* ppc stub */
+		".plt_branch.",		/* ppc stub */
+		NULL
+	};
+
+	const char * const *p;
+
+	for (p = ignored_symbols; *p; p++)
+		if (!strcmp(name, *p))
+			return true;
+
+	for (p = ignored_prefixes; *p; p++)
+		if (!strncmp(name, *p, strlen(*p)))
+			return true;
+
+	for (p = ignored_suffixes; *p; p++) {
+		int l = strlen(name) - strlen(*p);
+
+		if (l >= 0 && !strcmp(name + l, *p))
+			return true;
+	}
+
+	for (p = ignored_matches; *p; p++) {
+		if (strstr(name, *p))
+			return true;
+	}
+
+	if (type == 'U' || type == 'u')
+		return true;
+	/* exclude debugging symbols */
+	if (type == 'N' || type == 'n')
+		return true;
+
+	if (toupper(type) == 'A') {
+		/* Keep these useful absolute symbols */
+		if (strcmp(name, "__kernel_syscall_via_break") &&
+		    strcmp(name, "__kernel_syscall_via_epc") &&
+		    strcmp(name, "__kernel_sigtramp") &&
+		    strcmp(name, "__gp"))
+			return true;
+	}
+
+	return false;
+}
+
+struct test__vmlinux_matches_kallsyms_cb_args {
+	struct machine kallsyms;
+	struct map *vmlinux_map;
+	bool header_printed;
+};
+
+static int test__vmlinux_matches_kallsyms_cb1(struct map *map, void *data)
+{
+	struct test__vmlinux_matches_kallsyms_cb_args *args = data;
+	struct dso *dso = map__dso(map);
+	/*
+	 * If it is the kernel, kallsyms is always "[kernel.kallsyms]", while
+	 * the kernel will have the path for the vmlinux file being used, so use
+	 * the short name, less descriptive but the same ("[kernel]" in both
+	 * cases.
+	 */
+	struct map *pair = maps__find_by_name(args->kallsyms.kmaps,
+					(dso__kernel(dso) ? dso__short_name(dso) : dso__name(dso)));
+
+	if (pair) {
+		map__set_priv(pair);
+		map__put(pair);
+	} else {
+		if (!args->header_printed) {
+			pr_info("WARN: Maps only in vmlinux:\n");
+			args->header_printed = true;
+		}
+		map__fprintf(map, stderr);
+	}
+	return 0;
+}
+
+static int test__vmlinux_matches_kallsyms_cb2(struct map *map, void *data)
+{
+	struct test__vmlinux_matches_kallsyms_cb_args *args = data;
+	struct map *pair;
+	u64 mem_start = map__unmap_ip(args->vmlinux_map, map__start(map));
+	u64 mem_end = map__unmap_ip(args->vmlinux_map, map__end(map));
+
+	pair = maps__find(args->kallsyms.kmaps, mem_start);
+
+	if (pair != NULL && !map__priv(pair) && map__start(pair) == mem_start) {
+		struct dso *dso = map__dso(map);
+
+		if (!args->header_printed) {
+			pr_info("WARN: Maps in vmlinux with a different name in kallsyms:\n");
+			args->header_printed = true;
+		}
+
+		pr_info("WARN: %" PRIx64 "-%" PRIx64 " %" PRIx64 " %s in kallsyms as",
+			map__start(map), map__end(map), map__pgoff(map), dso__name(dso));
+		if (mem_end != map__end(pair))
+			pr_info(":\nWARN: *%" PRIx64 "-%" PRIx64 " %" PRIx64,
+				map__start(pair), map__end(pair), map__pgoff(pair));
+		pr_info(" %s\n", dso__name(dso));
+		map__set_priv(pair);
+	}
+	map__put(pair);
+	return 0;
+}
+
+static int test__vmlinux_matches_kallsyms_cb3(struct map *map, void *data)
+{
+	struct test__vmlinux_matches_kallsyms_cb_args *args = data;
+
+	if (!map__priv(map)) {
+		if (!args->header_printed) {
+			pr_info("WARN: Maps only in kallsyms:\n");
+			args->header_printed = true;
+		}
+		map__fprintf(map, stderr);
+	}
+	return 0;
+}
+
+static int test__vmlinux_matches_kallsyms(struct test_suite *test __maybe_unused,
+					int subtest __maybe_unused)
+{
+	int err = TEST_FAIL;
+	struct rb_node *nd;
+	struct symbol *sym;
+	struct map *kallsyms_map;
+	struct machine vmlinux = { 0 };
+	struct maps *maps;
+	u64 mem_start, mem_end;
+	struct test__vmlinux_matches_kallsyms_cb_args args;
+
+	/*
+	 * Step 1:
+	 *
+	 * Init the machines that will hold kernel, modules obtained from
+	 * both vmlinux + .ko files and from /proc/kallsyms split by modules.
+	 */
+	if (machine__init(&args.kallsyms, "", HOST_KERNEL_ID))
+		goto out;
+	if (machine__init(&vmlinux, "", HOST_KERNEL_ID))
+		goto out;
+
+	maps = machine__kernel_maps(&vmlinux);
+
+	/*
+	 * Step 2:
+	 *
+	 * Create the kernel maps for kallsyms and the DSO where we will then
+	 * load /proc/kallsyms. Also create the modules maps from /proc/modules
+	 * and find the .ko files that match them in /lib/modules/`uname -r`/.
+	 */
+	if (machine__create_kernel_maps(&args.kallsyms) < 0) {
+		pr_debug("machine__create_kernel_maps failed");
+		err = TEST_SKIP;
+		goto out;
+	}
+
+	/*
+	 * Step 3:
+	 *
+	 * Load and split /proc/kallsyms into multiple maps, one per module.
+	 * Do not use kcore, as this test was designed before kcore support
+	 * and has parts that only make sense if using the non-kcore code.
+	 * XXX: extend it to stress the kcorre code as well, hint: the list
+	 * of modules extracted from /proc/kcore, in its current form, can't
+	 * be compacted against the list of modules found in the "vmlinux"
+	 * code and with the one got from /proc/modules from the "kallsyms" code.
+	 */
+	if (machine__load_kallsyms(&args.kallsyms, "/proc/kallsyms") <= 0) {
+		pr_debug("machine__load_kallsyms failed");
+		err = TEST_SKIP;
+		goto out;
+	}
+
+	/*
+	 * Step 4:
+	 *
+	 * kallsyms will be internally on demand sorted by name so that we can
+	 * find the reference relocation * symbol, i.e. the symbol we will use
+	 * to see if the running kernel was relocated by checking if it has the
+	 * same value in the vmlinux file we load.
+	 */
+	kallsyms_map = machine__kernel_map(&args.kallsyms);
+
+	/*
+	 * Step 5:
+	 *
+	 * Now repeat step 2, this time for the vmlinux file we'll auto-locate.
+	 */
+	if (machine__create_kernel_maps(&vmlinux) < 0) {
+		pr_info("machine__create_kernel_maps failed");
+		goto out;
+	}
+
+	args.vmlinux_map = machine__kernel_map(&vmlinux);
+
+	/*
+	 * Step 6:
+	 *
+	 * Locate a vmlinux file in the vmlinux path that has a buildid that
+	 * matches the one of the running kernel.
+	 *
+	 * While doing that look if we find the ref reloc symbol, if we find it
+	 * we'll have its ref_reloc_symbol.unrelocated_addr and then
+	 * maps__reloc_vmlinux will notice and set proper ->[un]map_ip routines
+	 * to fixup the symbols.
+	 */
+	if (machine__load_vmlinux_path(&vmlinux) <= 0) {
+		pr_info("Couldn't find a vmlinux that matches the kernel running on this machine, skipping test\n");
+		err = TEST_SKIP;
+		goto out;
+	}
+
+	err = 0;
+	/*
+	 * Step 7:
+	 *
+	 * Now look at the symbols in the vmlinux DSO and check if we find all of them
+	 * in the kallsyms dso. For the ones that are in both, check its names and
+	 * end addresses too.
+	 */
+	map__for_each_symbol(args.vmlinux_map, sym, nd) {
+		struct symbol *pair, *first_pair;
+
+		sym  = rb_entry(nd, struct symbol, rb_node);
+
+		if (sym->start == sym->end)
+			continue;
+
+		mem_start = map__unmap_ip(args.vmlinux_map, sym->start);
+		mem_end = map__unmap_ip(args.vmlinux_map, sym->end);
+
+		first_pair = machine__find_kernel_symbol(&args.kallsyms, mem_start, NULL);
+		pair = first_pair;
+
+		if (pair && UM(pair->start) == mem_start) {
+next_pair:
+			if (arch__compare_symbol_names(sym->name, pair->name) == 0) {
+				/*
+				 * kallsyms don't have the symbol end, so we
+				 * set that by using the next symbol start - 1,
+				 * in some cases we get this up to a page
+				 * wrong, trace_kmalloc when I was developing
+				 * this code was one such example, 2106 bytes
+				 * off the real size. More than that and we
+				 * _really_ have a problem.
+				 */
+				s64 skew = mem_end - UM(pair->end);
+				if (llabs(skew) >= page_size)
+					pr_debug("WARN: %#" PRIx64 ": diff end addr for %s v: %#" PRIx64 " k: %#" PRIx64 "\n",
+						 mem_start, sym->name, mem_end,
+						 UM(pair->end));
+
+				/*
+				 * Do not count this as a failure, because we
+				 * could really find a case where it's not
+				 * possible to get proper function end from
+				 * kallsyms.
+				 */
+				continue;
+			} else {
+				pair = machine__find_kernel_symbol_by_name(&args.kallsyms,
+									   sym->name, NULL);
+				if (pair) {
+					if (UM(pair->start) == mem_start)
+						goto next_pair;
+
+					pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n",
+						 mem_start, sym->name, pair->name);
+				} else {
+					pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n",
+						 mem_start, sym->name, first_pair->name);
+				}
+
+				continue;
+			}
+		} else if (mem_start == map__end(args.kallsyms.vmlinux_map)) {
+			/*
+			 * Ignore aliases to _etext, i.e. to the end of the kernel text area,
+			 * such as __indirect_thunk_end.
+			 */
+			continue;
+		} else if (is_ignored_symbol(sym->name, symbol__type(sym))) {
+			/*
+			 * Ignore hidden symbols, see scripts/kallsyms.c for the details
+			 */
+			continue;
+		} else {
+			pr_debug("ERR : %#" PRIx64 ": %s not on kallsyms\n",
+				 mem_start, sym->name);
+		}
+
+		err = -1;
+	}
+
+	if (verbose <= 0)
+		goto out;
+
+	args.header_printed = false;
+	maps__for_each_map(maps, test__vmlinux_matches_kallsyms_cb1, &args);
+
+	args.header_printed = false;
+	maps__for_each_map(maps, test__vmlinux_matches_kallsyms_cb2, &args);
+
+	args.header_printed = false;
+	maps = machine__kernel_maps(&args.kallsyms);
+	maps__for_each_map(maps, test__vmlinux_matches_kallsyms_cb3, &args);
+
+out:
+	machine__exit(&args.kallsyms);
+	machine__exit(&vmlinux);
+	return err;
+}
+
+DEFINE_SUITE("vmlinux symtab matches kallsyms", vmlinux_matches_kallsyms);