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

6 files changed, 282 insertions, 0 deletions

diff --git a/tools/testing/selftests/lkdtm/.gitignore b/tools/testing/selftests/lkdtm/.gitignore
new file mode 100644
index 000000000..d4b0be857
--- /dev/null
+++ b/tools/testing/selftests/lkdtm/.gitignore
@@ -0,0 +1,3 @@
+*.sh
+!run.sh
+!stack-entropy.sh
diff --git a/tools/testing/selftests/lkdtm/Makefile b/tools/testing/selftests/lkdtm/Makefile
new file mode 100644
index 000000000..c71109cee
--- /dev/null
+++ b/tools/testing/selftests/lkdtm/Makefile
@@ -0,0 +1,13 @@
+# SPDX-License-Identifier: GPL-2.0
+# Makefile for LKDTM regression tests
+
+include ../lib.mk
+
+# NOTE: $(OUTPUT) won't get default value if used before lib.mk
+TEST_FILES := tests.txt
+TEST_PROGS := stack-entropy.sh
+TEST_GEN_PROGS = $(patsubst %,$(OUTPUT)/%.sh,$(shell awk '{print $$1}' tests.txt | sed -e 's/\#//'))
+all: $(TEST_GEN_PROGS)
+
+$(OUTPUT)/%: run.sh tests.txt
+	install -m 0744 run.sh $@
diff --git a/tools/testing/selftests/lkdtm/config b/tools/testing/selftests/lkdtm/config
new file mode 100644
index 000000000..bd09fdaf5
--- /dev/null
+++ b/tools/testing/selftests/lkdtm/config
@@ -0,0 +1,14 @@
+CONFIG_LKDTM=y
+CONFIG_DEBUG_LIST=y
+CONFIG_SLAB_FREELIST_HARDENED=y
+CONFIG_FORTIFY_SOURCE=y
+CONFIG_KSTACK_ERASE=y
+CONFIG_HARDENED_USERCOPY=y
+CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT=y
+CONFIG_INIT_ON_FREE_DEFAULT_ON=y
+CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y
+CONFIG_UBSAN=y
+CONFIG_UBSAN_BOUNDS=y
+CONFIG_STACKPROTECTOR_STRONG=y
+CONFIG_SLUB_DEBUG=y
+CONFIG_SLUB_DEBUG_ON=y
diff --git a/tools/testing/selftests/lkdtm/run.sh b/tools/testing/selftests/lkdtm/run.sh
new file mode 100755
index 000000000..95e904959
--- /dev/null
+++ b/tools/testing/selftests/lkdtm/run.sh
@@ -0,0 +1,112 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# This reads tests.txt for the list of LKDTM tests to invoke. Any marked
+# with a leading "#" are skipped. The rest of the line after the
+# test name is either the text to look for in dmesg for a "success",
+# or the rationale for why a test is marked to be skipped.
+#
+set -e
+TRIGGER=/sys/kernel/debug/provoke-crash/DIRECT
+CLEAR_ONCE=/sys/kernel/debug/clear_warn_once
+KSELFTEST_SKIP_TEST=4
+
+# Verify we have LKDTM available in the kernel.
+if [ ! -r $TRIGGER ] ; then
+	/sbin/modprobe -q lkdtm || true
+	if [ ! -r $TRIGGER ] ; then
+		echo "Cannot find $TRIGGER (missing CONFIG_LKDTM?)"
+	else
+		echo "Cannot write $TRIGGER (need to run as root?)"
+	fi
+	# Skip this test
+	exit $KSELFTEST_SKIP_TEST
+fi
+
+# Figure out which test to run from our script name.
+test=$(basename $0 .sh)
+# Look up details about the test from master list of LKDTM tests.
+line=$(grep -E '^#?'"$test"'\b' tests.txt)
+if [ -z "$line" ]; then
+	echo "Skipped: missing test '$test' in tests.txt"
+	exit $KSELFTEST_SKIP_TEST
+fi
+# Check that the test is known to LKDTM.
+if ! grep -E -q '^'"$test"'$' "$TRIGGER" ; then
+	echo "Skipped: test '$test' missing in $TRIGGER!"
+	exit $KSELFTEST_SKIP_TEST
+fi
+
+# Extract notes/expected output from test list.
+test=$(echo "$line" | cut -d" " -f1)
+if echo "$line" | grep -q ' ' ; then
+	expect=$(echo "$line" | cut -d" " -f2-)
+else
+	expect=""
+fi
+
+# If the test is commented out, report a skip
+if echo "$test" | grep -q '^#' ; then
+	test=$(echo "$test" | cut -c2-)
+	if [ -z "$expect" ]; then
+		expect="crashes entire system"
+	fi
+	echo "Skipping $test: $expect"
+	exit $KSELFTEST_SKIP_TEST
+fi
+
+# If no expected output given, assume an Oops with back trace is success.
+repeat=1
+if [ -z "$expect" ]; then
+	expect="call trace:"
+else
+	if echo "$expect" | grep -q '^repeat:' ; then
+		repeat=$(echo "$expect" | cut -d' ' -f1 | cut -d: -f2)
+		expect=$(echo "$expect" | cut -d' ' -f2-)
+	fi
+fi
+
+# Prepare log for report checking
+LOG=$(mktemp --tmpdir -t lkdtm-log-XXXXXX)
+DMESG=$(mktemp --tmpdir -t lkdtm-dmesg-XXXXXX)
+cleanup() {
+	rm -f "$LOG" "$DMESG"
+}
+trap cleanup EXIT
+
+# Reset WARN_ONCE counters so we trip it each time this runs.
+if [ -w $CLEAR_ONCE ] ; then
+	echo 1 > $CLEAR_ONCE
+fi
+
+# Save existing dmesg so we can detect new content below
+dmesg > "$DMESG"
+
+# Since the kernel is likely killing the process writing to the trigger
+# file, it must not be the script's shell itself. i.e. we cannot do:
+#     echo "$test" >"$TRIGGER"
+# Instead, use "cat" to take the signal. Since the shell will yell about
+# the signal that killed the subprocess, we must ignore the failure and
+# continue. However we don't silence stderr since there might be other
+# useful details reported there in the case of other unexpected conditions.
+for i in $(seq 1 $repeat); do
+	echo "$test" | cat >"$TRIGGER" || true
+done
+
+# Record and dump the results
+dmesg | comm --nocheck-order -13 "$DMESG" - > "$LOG" || true
+
+cat "$LOG"
+# Check for expected output
+if grep -E -qi "$expect" "$LOG" ; then
+	echo "$test: saw '$expect': ok"
+	exit 0
+else
+	if grep -E -qi XFAIL: "$LOG" ; then
+		echo "$test: saw 'XFAIL': [SKIP]"
+		exit $KSELFTEST_SKIP_TEST
+	else
+		echo "$test: missing '$expect': [FAIL]"
+		exit 1
+	fi
+fi
diff --git a/tools/testing/selftests/lkdtm/stack-entropy.sh b/tools/testing/selftests/lkdtm/stack-entropy.sh
new file mode 100755
index 000000000..14fedeef7
--- /dev/null
+++ b/tools/testing/selftests/lkdtm/stack-entropy.sh
@@ -0,0 +1,51 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# Measure kernel stack entropy by sampling via LKDTM's REPORT_STACK test.
+set -e
+samples="${1:-1000}"
+TRIGGER=/sys/kernel/debug/provoke-crash/DIRECT
+KSELFTEST_SKIP_TEST=4
+
+# Verify we have LKDTM available in the kernel.
+if [ ! -r $TRIGGER ] ; then
+	/sbin/modprobe -q lkdtm || true
+	if [ ! -r $TRIGGER ] ; then
+		echo "Cannot find $TRIGGER (missing CONFIG_LKDTM?)"
+	else
+		echo "Cannot write $TRIGGER (need to run as root?)"
+	fi
+	# Skip this test
+	exit $KSELFTEST_SKIP_TEST
+fi
+
+# Capture dmesg continuously since it may fill up depending on sample size.
+log=$(mktemp -t stack-entropy-XXXXXX)
+dmesg --follow >"$log" & pid=$!
+report=-1
+for i in $(seq 1 $samples); do
+        echo "REPORT_STACK" > $TRIGGER
+	if [ -t 1 ]; then
+		percent=$(( 100 * $i / $samples ))
+		if [ "$percent" -ne "$report" ]; then
+			/bin/echo -en "$percent%\r"
+			report="$percent"
+		fi
+	fi
+done
+kill "$pid"
+
+# Count unique offsets since last run.
+seen=$(tac "$log" | grep -m1 -B"$samples"0 'Starting stack offset' | \
+	grep 'Stack offset' | awk '{print $NF}' | sort | uniq -c | wc -l)
+bits=$(echo "obase=2; $seen" | bc | wc -L)
+echo "Bits of stack entropy: $bits"
+rm -f "$log"
+
+# We would expect any functional stack randomization to be at least 5 bits.
+if [ "$bits" -lt 5 ]; then
+	echo "Stack entropy is low! Booted without 'randomize_kstack_offset=y'?"
+	exit 1
+else
+	exit 0
+fi
diff --git a/tools/testing/selftests/lkdtm/tests.txt b/tools/testing/selftests/lkdtm/tests.txt
new file mode 100644
index 000000000..bec57a029
--- /dev/null
+++ b/tools/testing/selftests/lkdtm/tests.txt
@@ -0,0 +1,89 @@
+#PANIC
+#PANIC_STOP_IRQOFF Crashes entire system
+#PANIC_IN_HARDIRQ Crashes entire system
+BUG kernel BUG at
+#BUG_IN_HARDIRQ Crashes entire system
+WARNING WARNING:
+WARNING_MESSAGE message trigger
+EXCEPTION
+#LOOP Hangs the system
+#EXHAUST_STACK Corrupts memory on failure
+#CORRUPT_STACK Crashes entire system on success
+#CORRUPT_STACK_STRONG Crashes entire system on success
+ARRAY_BOUNDS call trace:|UBSAN: array-index-out-of-bounds
+FAM_BOUNDS call trace:|UBSAN: array-index-out-of-bounds
+PTR_BOUNDS call trace:|UBSAN: array-index-out-of-bounds
+CORRUPT_LIST_ADD list_add corruption
+CORRUPT_LIST_DEL list_del corruption
+STACK_GUARD_PAGE_LEADING
+STACK_GUARD_PAGE_TRAILING
+REPORT_STACK_CANARY repeat:2 ok: stack canaries differ
+UNSET_SMEP pinned CR4 bits changed:
+DOUBLE_FAULT
+CORRUPT_PAC
+UNALIGNED_LOAD_STORE_WRITE
+SLAB_LINEAR_OVERFLOW
+VMALLOC_LINEAR_OVERFLOW
+#WRITE_AFTER_FREE Corrupts memory on failure
+READ_AFTER_FREE call trace:|Memory correctly poisoned
+#WRITE_BUDDY_AFTER_FREE Corrupts memory on failure
+READ_BUDDY_AFTER_FREE call trace:|Memory correctly poisoned
+SLAB_INIT_ON_ALLOC Memory appears initialized
+BUDDY_INIT_ON_ALLOC Memory appears initialized
+SLAB_FREE_DOUBLE
+SLAB_FREE_CROSS
+SLAB_FREE_PAGE
+#SOFTLOCKUP Hangs the system
+#HARDLOCKUP Hangs the system
+#SMP_CALL_LOCKUP Hangs the system
+#SPINLOCKUP Hangs the system
+#HUNG_TASK Hangs the system
+EXEC_DATA
+EXEC_STACK
+EXEC_KMALLOC
+EXEC_VMALLOC
+EXEC_RODATA
+EXEC_USERSPACE
+EXEC_NULL
+ACCESS_USERSPACE
+ACCESS_NULL
+WRITE_RO
+WRITE_RO_AFTER_INIT
+WRITE_KERN
+WRITE_OPD
+REFCOUNT_INC_OVERFLOW
+REFCOUNT_ADD_OVERFLOW
+REFCOUNT_INC_NOT_ZERO_OVERFLOW
+REFCOUNT_ADD_NOT_ZERO_OVERFLOW
+REFCOUNT_DEC_ZERO
+REFCOUNT_DEC_NEGATIVE Negative detected: saturated
+REFCOUNT_DEC_AND_TEST_NEGATIVE Negative detected: saturated
+REFCOUNT_SUB_AND_TEST_NEGATIVE Negative detected: saturated
+REFCOUNT_INC_ZERO
+REFCOUNT_ADD_ZERO
+REFCOUNT_INC_SATURATED Saturation detected: still saturated
+REFCOUNT_DEC_SATURATED Saturation detected: still saturated
+REFCOUNT_ADD_SATURATED Saturation detected: still saturated
+REFCOUNT_INC_NOT_ZERO_SATURATED
+REFCOUNT_ADD_NOT_ZERO_SATURATED
+REFCOUNT_DEC_AND_TEST_SATURATED Saturation detected: still saturated
+REFCOUNT_SUB_AND_TEST_SATURATED Saturation detected: still saturated
+#REFCOUNT_TIMING timing only
+#ATOMIC_TIMING timing only
+USERCOPY_SLAB_SIZE_TO
+USERCOPY_SLAB_SIZE_FROM
+USERCOPY_SLAB_WHITELIST_TO
+USERCOPY_SLAB_WHITELIST_FROM
+USERCOPY_STACK_FRAME_TO
+USERCOPY_STACK_FRAME_FROM
+USERCOPY_STACK_BEYOND
+USERCOPY_KERNEL
+KSTACK_ERASE OK: the rest of the thread stack is properly erased
+CFI_FORWARD_PROTO
+CFI_BACKWARD call trace:|ok: control flow unchanged
+FORTIFY_STRSCPY detected buffer overflow
+FORTIFY_STR_MEMBER detected buffer overflow
+FORTIFY_MEM_OBJECT detected buffer overflow
+FORTIFY_MEM_MEMBER detected field-spanning write
+PPC_SLB_MULTIHIT Recovered
+#PPC_RADIX_TLBIEL Triggers unrecoverable MCE