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

8 files changed, 521 insertions, 0 deletions

diff --git a/tools/testing/selftests/prctl/.gitignore b/tools/testing/selftests/prctl/.gitignore
new file mode 100644
index 000000000..05d5e3166
--- /dev/null
+++ b/tools/testing/selftests/prctl/.gitignore
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
+disable-tsc-ctxt-sw-stress-test
+disable-tsc-on-off-stress-test
+disable-tsc-test
+set-anon-vma-name-test
+set-process-name
diff --git a/tools/testing/selftests/prctl/Makefile b/tools/testing/selftests/prctl/Makefile
new file mode 100644
index 000000000..e770e86fa
--- /dev/null
+++ b/tools/testing/selftests/prctl/Makefile
@@ -0,0 +1,14 @@
+# SPDX-License-Identifier: GPL-2.0
+ifndef CROSS_COMPILE
+ARCH ?= $(shell uname -m 2>/dev/null || echo not)
+override ARCH := $(shell echo $(ARCH) | sed -e s/i.86/x86/ -e s/x86_64/x86/)
+
+ifeq ($(ARCH),x86)
+TEST_PROGS := disable-tsc-ctxt-sw-stress-test disable-tsc-on-off-stress-test \
+		disable-tsc-test set-anon-vma-name-test set-process-name
+all: $(TEST_PROGS)
+
+include ../lib.mk
+
+endif
+endif
diff --git a/tools/testing/selftests/prctl/config b/tools/testing/selftests/prctl/config
new file mode 100644
index 000000000..c6ed03c54
--- /dev/null
+++ b/tools/testing/selftests/prctl/config
@@ -0,0 +1 @@
+CONFIG_ANON_VMA_NAME=y
diff --git a/tools/testing/selftests/prctl/disable-tsc-ctxt-sw-stress-test.c b/tools/testing/selftests/prctl/disable-tsc-ctxt-sw-stress-test.c
new file mode 100644
index 000000000..6d1a5ee8e
--- /dev/null
+++ b/tools/testing/selftests/prctl/disable-tsc-ctxt-sw-stress-test.c
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Tests for prctl(PR_GET_TSC, ...) / prctl(PR_SET_TSC, ...)
+ *
+ * Tests if the control register is updated correctly
+ * at context switches
+ *
+ * Warning: this test will cause a very high load for a few seconds
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <signal.h>
+#include <inttypes.h>
+#include <wait.h>
+
+
+#include <sys/prctl.h>
+#include <linux/prctl.h>
+
+/* Get/set the process' ability to use the timestamp counter instruction */
+#ifndef PR_GET_TSC
+#define PR_GET_TSC 25
+#define PR_SET_TSC 26
+# define PR_TSC_ENABLE		1   /* allow the use of the timestamp counter */
+# define PR_TSC_SIGSEGV		2   /* throw a SIGSEGV instead of reading the TSC */
+#endif
+
+static uint64_t rdtsc(void)
+{
+uint32_t lo, hi;
+/* We cannot use "=A", since this would use %rax on x86_64 */
+__asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
+return (uint64_t)hi << 32 | lo;
+}
+
+static void sigsegv_expect(int sig)
+{
+	/* */
+}
+
+static void segvtask(void)
+{
+	if (prctl(PR_SET_TSC, PR_TSC_SIGSEGV) < 0)
+	{
+		perror("prctl");
+		exit(0);
+	}
+	signal(SIGSEGV, sigsegv_expect);
+	alarm(10);
+	rdtsc();
+	fprintf(stderr, "FATAL ERROR, rdtsc() succeeded while disabled\n");
+	exit(0);
+}
+
+
+static void sigsegv_fail(int sig)
+{
+	fprintf(stderr, "FATAL ERROR, rdtsc() failed while enabled\n");
+	exit(0);
+}
+
+static void rdtsctask(void)
+{
+	if (prctl(PR_SET_TSC, PR_TSC_ENABLE) < 0)
+	{
+		perror("prctl");
+		exit(0);
+	}
+	signal(SIGSEGV, sigsegv_fail);
+	alarm(10);
+	for(;;) rdtsc();
+}
+
+
+int main(void)
+{
+	int n_tasks = 100, i;
+
+	fprintf(stderr, "[No further output means we're all right]\n");
+
+	for (i=0; i<n_tasks; i++)
+		if (fork() == 0)
+		{
+			if (i & 1)
+				segvtask();
+			else
+				rdtsctask();
+		}
+
+	for (i=0; i<n_tasks; i++)
+		wait(NULL);
+
+	exit(0);
+}
+
diff --git a/tools/testing/selftests/prctl/disable-tsc-on-off-stress-test.c b/tools/testing/selftests/prctl/disable-tsc-on-off-stress-test.c
new file mode 100644
index 000000000..d39511eb9
--- /dev/null
+++ b/tools/testing/selftests/prctl/disable-tsc-on-off-stress-test.c
@@ -0,0 +1,97 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Tests for prctl(PR_GET_TSC, ...) / prctl(PR_SET_TSC, ...)
+ *
+ * Tests if the control register is updated correctly
+ * when set with prctl()
+ *
+ * Warning: this test will cause a very high load for a few seconds
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <signal.h>
+#include <inttypes.h>
+#include <wait.h>
+
+
+#include <sys/prctl.h>
+#include <linux/prctl.h>
+
+/* Get/set the process' ability to use the timestamp counter instruction */
+#ifndef PR_GET_TSC
+#define PR_GET_TSC 25
+#define PR_SET_TSC 26
+# define PR_TSC_ENABLE		1   /* allow the use of the timestamp counter */
+# define PR_TSC_SIGSEGV		2   /* throw a SIGSEGV instead of reading the TSC */
+#endif
+
+/* snippet from wikipedia :-) */
+
+static uint64_t rdtsc(void)
+{
+uint32_t lo, hi;
+/* We cannot use "=A", since this would use %rax on x86_64 */
+__asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
+return (uint64_t)hi << 32 | lo;
+}
+
+int should_segv = 0;
+
+static void sigsegv_cb(int sig)
+{
+	if (!should_segv)
+	{
+		fprintf(stderr, "FATAL ERROR, rdtsc() failed while enabled\n");
+		exit(0);
+	}
+	if (prctl(PR_SET_TSC, PR_TSC_ENABLE) < 0)
+	{
+		perror("prctl");
+		exit(0);
+	}
+	should_segv = 0;
+
+	rdtsc();
+}
+
+static void task(void)
+{
+	signal(SIGSEGV, sigsegv_cb);
+	alarm(10);
+	for(;;)
+	{
+		rdtsc();
+		if (should_segv)
+		{
+			fprintf(stderr, "FATAL ERROR, rdtsc() succeeded while disabled\n");
+			exit(0);
+		}
+		if (prctl(PR_SET_TSC, PR_TSC_SIGSEGV) < 0)
+		{
+			perror("prctl");
+			exit(0);
+		}
+		should_segv = 1;
+	}
+}
+
+
+int main(void)
+{
+	int n_tasks = 100, i;
+
+	fprintf(stderr, "[No further output means we're all right]\n");
+
+	for (i=0; i<n_tasks; i++)
+		if (fork() == 0)
+			task();
+
+	for (i=0; i<n_tasks; i++)
+		wait(NULL);
+
+	exit(0);
+}
+
diff --git a/tools/testing/selftests/prctl/disable-tsc-test.c b/tools/testing/selftests/prctl/disable-tsc-test.c
new file mode 100644
index 000000000..f84d4ee11
--- /dev/null
+++ b/tools/testing/selftests/prctl/disable-tsc-test.c
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Tests for prctl(PR_GET_TSC, ...) / prctl(PR_SET_TSC, ...)
+ *
+ * Basic test to test behaviour of PR_GET_TSC and PR_SET_TSC
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <signal.h>
+#include <inttypes.h>
+
+
+#include <sys/prctl.h>
+#include <linux/prctl.h>
+
+/* Get/set the process' ability to use the timestamp counter instruction */
+#ifndef PR_GET_TSC
+#define PR_GET_TSC 25
+#define PR_SET_TSC 26
+# define PR_TSC_ENABLE		1   /* allow the use of the timestamp counter */
+# define PR_TSC_SIGSEGV		2   /* throw a SIGSEGV instead of reading the TSC */
+#endif
+
+const char *tsc_names[] =
+{
+	[0] = "[not set]",
+	[PR_TSC_ENABLE] = "PR_TSC_ENABLE",
+	[PR_TSC_SIGSEGV] = "PR_TSC_SIGSEGV",
+};
+
+static uint64_t rdtsc(void)
+{
+uint32_t lo, hi;
+/* We cannot use "=A", since this would use %rax on x86_64 */
+__asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
+return (uint64_t)hi << 32 | lo;
+}
+
+static void sigsegv_cb(int sig)
+{
+	int tsc_val = 0;
+
+	printf("[ SIG_SEGV ]\n");
+	printf("prctl(PR_GET_TSC, &tsc_val); ");
+	fflush(stdout);
+
+	if ( prctl(PR_GET_TSC, &tsc_val) == -1)
+		perror("prctl");
+
+	printf("tsc_val == %s\n", tsc_names[tsc_val]);
+	printf("prctl(PR_SET_TSC, PR_TSC_ENABLE)\n");
+	fflush(stdout);
+	if ( prctl(PR_SET_TSC, PR_TSC_ENABLE) == -1)
+		perror("prctl");
+
+	printf("rdtsc() == ");
+}
+
+int main(void)
+{
+	int tsc_val = 0;
+
+	signal(SIGSEGV, sigsegv_cb);
+
+	printf("rdtsc() == %llu\n", (unsigned long long)rdtsc());
+	printf("prctl(PR_GET_TSC, &tsc_val); ");
+	fflush(stdout);
+
+	if ( prctl(PR_GET_TSC, &tsc_val) == -1)
+		perror("prctl");
+
+	printf("tsc_val == %s\n", tsc_names[tsc_val]);
+	printf("rdtsc() == %llu\n", (unsigned long long)rdtsc());
+	printf("prctl(PR_SET_TSC, PR_TSC_ENABLE)\n");
+	fflush(stdout);
+
+	if ( prctl(PR_SET_TSC, PR_TSC_ENABLE) == -1)
+		perror("prctl");
+
+	printf("rdtsc() == %llu\n", (unsigned long long)rdtsc());
+	printf("prctl(PR_SET_TSC, PR_TSC_SIGSEGV)\n");
+	fflush(stdout);
+
+	if ( prctl(PR_SET_TSC, PR_TSC_SIGSEGV) == -1)
+		perror("prctl");
+
+	printf("rdtsc() == ");
+	fflush(stdout);
+	printf("%llu\n", (unsigned long long)rdtsc());
+	fflush(stdout);
+
+	exit(EXIT_SUCCESS);
+}
+
diff --git a/tools/testing/selftests/prctl/set-anon-vma-name-test.c b/tools/testing/selftests/prctl/set-anon-vma-name-test.c
new file mode 100644
index 000000000..5f9589534
--- /dev/null
+++ b/tools/testing/selftests/prctl/set-anon-vma-name-test.c
@@ -0,0 +1,115 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This test covers the anonymous VMA naming functionality through prctl calls
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/prctl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/mman.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "kselftest_harness.h"
+
+#define AREA_SIZE 1024
+
+#define GOOD_NAME "goodname"
+#define BAD_NAME "badname\1"
+
+#ifndef PR_SET_VMA
+#define PR_SET_VMA 0x53564d41
+#define PR_SET_VMA_ANON_NAME 0
+#endif
+
+
+int rename_vma(unsigned long addr, unsigned long size, char *name)
+{
+	int res;
+
+	res = prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, addr, size, name);
+	if (res < 0)
+		return -errno;
+	return res;
+}
+
+int was_renaming_successful(char *target_name, unsigned long ptr)
+{
+	FILE *maps_file;
+
+	char line_buf[512], name[128], mode[8];
+	unsigned long start_addr, end_addr, offset;
+	unsigned int major_id, minor_id, node_id;
+
+	char target_buf[128];
+	int res = 0, sscanf_res;
+
+	// The entry name in maps will be in format [anon:<target_name>]
+	sprintf(target_buf, "[anon:%s]", target_name);
+	maps_file = fopen("/proc/self/maps", "r");
+	if (!maps_file) {
+		printf("## /proc/self/maps file opening error\n");
+		return 0;
+	}
+
+	// Parse the maps file to find the entry we renamed
+	while (fgets(line_buf, sizeof(line_buf), maps_file)) {
+		sscanf_res = sscanf(line_buf, "%lx-%lx %7s %lx %u:%u %u %s", &start_addr,
+					&end_addr, mode, &offset, &major_id,
+					&minor_id, &node_id, name);
+		if (sscanf_res == EOF) {
+			res = 0;
+			printf("## EOF while parsing the maps file\n");
+			break;
+		}
+		if (!strcmp(name, target_buf) && start_addr == ptr) {
+			res = 1;
+			break;
+		}
+	}
+	fclose(maps_file);
+	return res;
+}
+
+FIXTURE(vma) {
+	void *ptr_anon, *ptr_not_anon;
+	int fd_not_anon;
+};
+
+FIXTURE_SETUP(vma) {
+	char template[] = "./set-anon-vma-test-XXXXXX";
+
+	self->ptr_anon = mmap(NULL, AREA_SIZE, PROT_READ | PROT_WRITE,
+					MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+	ASSERT_NE(self->ptr_anon, MAP_FAILED);
+
+	self->fd_not_anon = mkstemp(template);
+	ASSERT_NE(self->fd_not_anon, -1);
+	unlink(template);
+	ASSERT_EQ(ftruncate(self->fd_not_anon, AREA_SIZE), 0);
+	self->ptr_not_anon = mmap(NULL, AREA_SIZE, PROT_READ | PROT_WRITE,
+					MAP_PRIVATE, self->fd_not_anon, 0);
+	ASSERT_NE(self->ptr_not_anon, MAP_FAILED);
+	close(self->fd_not_anon);
+}
+
+FIXTURE_TEARDOWN(vma) {
+	munmap(self->ptr_anon, AREA_SIZE);
+	munmap(self->ptr_not_anon, AREA_SIZE);
+}
+
+TEST_F(vma, renaming) {
+	TH_LOG("Try to rename the VMA with correct parameters");
+	EXPECT_GE(rename_vma((unsigned long)self->ptr_anon, AREA_SIZE, GOOD_NAME), 0);
+	EXPECT_TRUE(was_renaming_successful(GOOD_NAME, (unsigned long)self->ptr_anon));
+
+	TH_LOG("Try to pass invalid name (with non-printable character \\1) to rename the VMA");
+	EXPECT_EQ(rename_vma((unsigned long)self->ptr_anon, AREA_SIZE, BAD_NAME), -EINVAL);
+
+	TH_LOG("Try to rename non-anonymous VMA");
+	EXPECT_EQ(rename_vma((unsigned long) self->ptr_not_anon, AREA_SIZE, GOOD_NAME), -EBADF);
+}
+
+TEST_HARNESS_MAIN
diff --git a/tools/testing/selftests/prctl/set-process-name.c b/tools/testing/selftests/prctl/set-process-name.c
new file mode 100644
index 000000000..3f7b146d3
--- /dev/null
+++ b/tools/testing/selftests/prctl/set-process-name.c
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This test covers the PR_SET_NAME functionality of prctl calls
+ */
+
+#include <errno.h>
+#include <sys/prctl.h>
+#include <string.h>
+
+#include "kselftest_harness.h"
+
+#define CHANGE_NAME "changename"
+#define EMPTY_NAME ""
+#define TASK_COMM_LEN 16
+#define MAX_PATH_LEN 50
+
+int set_name(char *name)
+{
+	int res;
+
+	res = prctl(PR_SET_NAME, name, NULL, NULL, NULL);
+
+	if (res < 0)
+		return -errno;
+	return res;
+}
+
+int check_is_name_correct(char *check_name)
+{
+	char name[TASK_COMM_LEN];
+	int res;
+
+	res = prctl(PR_GET_NAME, name, NULL, NULL, NULL);
+
+	if (res < 0)
+		return -errno;
+
+	return !strcmp(name, check_name);
+}
+
+int check_null_pointer(char *check_name)
+{
+	char *name = NULL;
+	int res;
+
+	res = prctl(PR_GET_NAME, name, NULL, NULL, NULL);
+
+	return res;
+}
+
+int check_name(void)
+{
+
+	int pid;
+
+	pid = getpid();
+	FILE *fptr = NULL;
+	char path[MAX_PATH_LEN] = {};
+	char name[TASK_COMM_LEN] = {};
+	char output[TASK_COMM_LEN] = {};
+	int j;
+
+	j = snprintf(path, MAX_PATH_LEN, "/proc/self/task/%d/comm", pid);
+	fptr = fopen(path, "r");
+	if (!fptr)
+		return -EIO;
+
+	fscanf(fptr, "%s", output);
+	if (ferror(fptr))
+		return -EIO;
+
+	int res = prctl(PR_GET_NAME, name, NULL, NULL, NULL);
+
+	if (res < 0)
+		return -errno;
+
+	return !strcmp(output, name);
+}
+
+TEST(rename_process) {
+
+	EXPECT_GE(set_name(CHANGE_NAME), 0);
+	EXPECT_TRUE(check_is_name_correct(CHANGE_NAME));
+
+	EXPECT_GE(set_name(EMPTY_NAME), 0);
+	EXPECT_TRUE(check_is_name_correct(EMPTY_NAME));
+
+	EXPECT_GE(set_name(CHANGE_NAME), 0);
+	EXPECT_LT(check_null_pointer(CHANGE_NAME), 0);
+
+	EXPECT_TRUE(check_name());
+}
+
+TEST_HARNESS_MAIN