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, 368 insertions, 0 deletions

diff --git a/scripts/decode_stacktrace.sh b/scripts/decode_stacktrace.sh
new file mode 100755
index 000000000..39d60d477
--- /dev/null
+++ b/scripts/decode_stacktrace.sh
@@ -0,0 +1,368 @@
+#!/usr/bin/env bash
+# SPDX-License-Identifier: GPL-2.0
+# (c) 2014, Sasha Levin <sasha.levin@oracle.com>
+#set -x
+
+usage() {
+	echo "Usage:"
+	echo "	$0 [-R] -r <release>"
+	echo "	$0 [-R] [<vmlinux> [<base_path>|auto [<modules_path>]]]"
+	echo "	$0 -h"
+	echo "Options:"
+	echo "  -R: decode return address instead of caller address."
+}
+
+# Try to find a Rust demangler
+if type llvm-cxxfilt >/dev/null 2>&1 ; then
+	cppfilt=llvm-cxxfilt
+elif type c++filt >/dev/null 2>&1 ; then
+	cppfilt=c++filt
+	cppfilt_opts=-i
+fi
+
+UTIL_SUFFIX=
+if [[ -z ${LLVM:-} ]]; then
+	UTIL_PREFIX=${CROSS_COMPILE:-}
+else
+	UTIL_PREFIX=llvm-
+	if [[ ${LLVM} == */ ]]; then
+		UTIL_PREFIX=${LLVM}${UTIL_PREFIX}
+	elif [[ ${LLVM} == -* ]]; then
+		UTIL_SUFFIX=${LLVM}
+	fi
+fi
+
+READELF=${UTIL_PREFIX}readelf${UTIL_SUFFIX}
+ADDR2LINE=${UTIL_PREFIX}addr2line${UTIL_SUFFIX}
+NM=${UTIL_PREFIX}nm${UTIL_SUFFIX}
+decode_retaddr=false
+
+if [[ $1 == "-h" ]] ; then
+	usage
+	exit 0
+elif [[ $1 == "-R" ]] ; then
+	decode_retaddr=true
+	shift 1
+fi
+
+if [[ $1 == "-r" ]] ; then
+	vmlinux=""
+	basepath="auto"
+	modpath=""
+	release=$2
+
+	for fn in {,/usr/lib/debug}/boot/vmlinux-$release{,.debug} /lib/modules/$release{,/build}/vmlinux ; do
+		if [ -e "$fn" ] ; then
+			vmlinux=$fn
+			break
+		fi
+	done
+
+	if [[ $vmlinux == "" ]] ; then
+		echo "ERROR! vmlinux image for release $release is not found" >&2
+		usage
+		exit 2
+	fi
+else
+	vmlinux=$1
+	basepath=${2-auto}
+	modpath=$3
+	release=""
+	debuginfod=
+
+	# Can we use debuginfod-find?
+	if type debuginfod-find >/dev/null 2>&1 ; then
+		debuginfod=${1-only}
+	fi
+
+	if [[ $vmlinux == "" && -z $debuginfod ]] ; then
+		echo "ERROR! vmlinux image must be specified" >&2
+		usage
+		exit 1
+	fi
+fi
+
+declare aarray_support=true
+declare -A cache 2>/dev/null
+if [[ $? != 0 ]]; then
+	aarray_support=false
+else
+	declare -A modcache
+fi
+
+find_module() {
+	if [[ -n $debuginfod ]] ; then
+		if [[ -n $modbuildid ]] ; then
+			debuginfod-find debuginfo $modbuildid && return
+		fi
+
+		# Only using debuginfod so don't try to find vmlinux module path
+		if [[ $debuginfod == "only" ]] ; then
+			return
+		fi
+	fi
+
+	if [ -z $release ] ; then
+		release=$(gdb -ex 'print init_uts_ns.name.release' -ex 'quit' -quiet -batch "$vmlinux" 2>/dev/null | sed -n 's/\$1 = "\(.*\)".*/\1/p')
+	fi
+	if [ -n "${release}" ] ; then
+		release_dirs="/usr/lib/debug/lib/modules/$release /lib/modules/$release"
+	fi
+
+	found_without_debug_info=false
+	for dir in "$modpath" "$(dirname "$vmlinux")" ${release_dirs}; do
+		if [ -n "${dir}" ] && [ -e "${dir}" ]; then
+			for fn in $(find "$dir" -name "${module//_/[-_]}.ko*") ; do
+				if ${READELF} -WS "$fn" | grep -qwF .debug_line ; then
+					echo $fn
+					return
+				fi
+				found_without_debug_info=true
+			done
+		fi
+	done
+
+	if [[ ${found_without_debug_info} == true ]]; then
+		echo "WARNING! No debugging info in module ${module}, rebuild with DEBUG_KERNEL and DEBUG_INFO" >&2
+	else
+		echo "WARNING! Cannot find .ko for module ${module}, please pass a valid module path" >&2
+	fi
+
+	return 1
+}
+
+parse_symbol() {
+	# The structure of symbol at this point is:
+	#   ([name]+[offset]/[total length])
+	#
+	# For example:
+	#   do_basic_setup+0x9c/0xbf
+
+	if [[ $module == "" ]] ; then
+		local objfile=$vmlinux
+	elif [[ $aarray_support == true && "${modcache[$module]+isset}" == "isset" ]]; then
+		local objfile=${modcache[$module]}
+	else
+		local objfile=$(find_module)
+		if [[ $objfile == "" ]] ; then
+			return
+		fi
+		if [[ $aarray_support == true ]]; then
+			modcache[$module]=$objfile
+		fi
+	fi
+
+	# Remove the englobing parenthesis
+	symbol=${symbol#\(}
+	symbol=${symbol%\)}
+
+	# Strip segment
+	local segment
+	if [[ $symbol == *:* ]] ; then
+		segment=${symbol%%:*}:
+		symbol=${symbol#*:}
+	fi
+
+	# Strip the symbol name so that we could look it up
+	local name=${symbol%+*}
+
+	# Use 'nm vmlinux' to figure out the base address of said symbol.
+	# It's actually faster to call it every time than to load it
+	# all into bash.
+	if [[ $aarray_support == true && "${cache[$module,$name]+isset}" == "isset" ]]; then
+		local base_addr=${cache[$module,$name]}
+	else
+		local base_addr=$(${NM} "$objfile" 2>/dev/null | awk '$3 == "'$name'" && ($2 == "t" || $2 == "T") {print $1; exit}')
+		if [[ $base_addr == "" ]] ; then
+			# address not found
+			return
+		fi
+		if [[ $aarray_support == true ]]; then
+			cache[$module,$name]="$base_addr"
+		fi
+	fi
+	# Let's start doing the math to get the exact address into the
+	# symbol. First, strip out the symbol total length.
+	local expr=${symbol%/*}
+	# Also parse the offset from symbol.
+	local offset=${expr#*+}
+	offset=$((offset))
+
+	# Now, replace the symbol name with the base address we found
+	# before.
+	expr=${expr/$name/0x$base_addr}
+
+	# Evaluate it to find the actual address
+	# The stack trace shows the return address, which is the next
+	# instruction after the actual call, so as long as it's in the same
+	# symbol, subtract one from that to point the call instruction.
+	if [[ $decode_retaddr == false && $offset != 0 ]]; then
+		expr=$((expr-1))
+	else
+		expr=$((expr))
+	fi
+	local address=$(printf "%x\n" "$expr")
+
+	# Pass it to addr2line to get filename and line number
+	# Could get more than one result
+	if [[ $aarray_support == true && "${cache[$module,$address]+isset}" == "isset" ]]; then
+		local code=${cache[$module,$address]}
+	else
+		local code=$(${ADDR2LINE} -i -e "$objfile" "$address" 2>/dev/null)
+		if [[ $aarray_support == true ]]; then
+			cache[$module,$address]=$code
+		fi
+	fi
+
+	# addr2line doesn't return a proper error code if it fails, so
+	# we detect it using the value it prints so that we could preserve
+	# the offset/size into the function and bail out
+	if [[ $code == "??:0" ]]; then
+		return
+	fi
+
+	# Strip out the base of the path on each line
+	code=$(while read -r line; do echo "${line#$basepath/}"; done <<< "$code")
+
+	# In the case of inlines, move everything to same line
+	code=${code//$'\n'/' '}
+
+	# Demangle if the name looks like a Rust symbol and if
+	# we got a Rust demangler
+	if [[ $name =~ ^_R && $cppfilt != "" ]] ; then
+		name=$("$cppfilt" "$cppfilt_opts" "$name")
+	fi
+
+	# Replace old address with pretty line numbers
+	symbol="$segment$name ($code)"
+}
+
+debuginfod_get_vmlinux() {
+	local vmlinux_buildid=${1##* }
+
+	if [[ $vmlinux != "" ]]; then
+		return
+	fi
+
+	if [[ $vmlinux_buildid =~ ^[0-9a-f]+ ]]; then
+		vmlinux=$(debuginfod-find debuginfo $vmlinux_buildid)
+		if [[ $? -ne 0 ]] ; then
+			echo "ERROR! vmlinux image not found via debuginfod-find" >&2
+			usage
+			exit 2
+		fi
+		return
+	fi
+	echo "ERROR! Build ID for vmlinux not found. Try passing -r or specifying vmlinux" >&2
+	usage
+	exit 2
+}
+
+decode_code() {
+	local scripts=`dirname "${BASH_SOURCE[0]}"`
+	local lim="Code: "
+
+	echo -n "${1%%${lim}*}"
+	echo "${lim}${1##*${lim}}" | $scripts/decodecode
+}
+
+handle_line() {
+	if [[ $basepath == "auto" && $vmlinux != "" ]] ; then
+		module=""
+		symbol="kernel_init+0x0/0x0"
+		parse_symbol
+		basepath=${symbol#kernel_init (}
+		basepath=${basepath%/init/main.c:*)}
+	fi
+
+	local words spaces
+
+	# Tokenize: words and spaces to preserve the alignment
+	read -ra words <<<"$1"
+	IFS='#' read -ra spaces <<<"$(shopt -s extglob; echo "${1//+([^[:space:]])/#}")"
+
+	# Remove hex numbers. Do it ourselves until it happens in the
+	# kernel
+
+	# We need to know the index of the last element before we
+	# remove elements because arrays are sparse
+	local last=$(( ${#words[@]} - 1 ))
+
+	for i in "${!words[@]}"; do
+		# Remove the address
+		if [[ ${words[$i]} =~ \[\<([^]]+)\>\] ]]; then
+			unset words[$i] spaces[$i]
+		fi
+	done
+
+	# Extract info after the symbol if present. E.g.:
+	# func_name+0x54/0x80 (P)
+	#                     ^^^
+	# The regex assumes only uppercase letters will be used. To be
+	# extended if needed.
+	local info_str=""
+	if [[ ${words[$last]} =~ \([A-Z]*\) ]]; then
+		info_str=${words[$last]}
+		unset words[$last] spaces[$last]
+		last=$(( $last - 1 ))
+	fi
+
+	# Join module name with its build id if present, as these were
+	# split during tokenization (e.g. "[module" and "modbuildid]").
+	if [[ ${words[$last]} =~ ^[0-9a-f]+\] ]]; then
+		words[$last-1]="${words[$last-1]} ${words[$last]}"
+		unset words[$last] spaces[$last]
+		last=$(( $last - 1 ))
+	fi
+
+	if [[ ${words[$last]} =~ \[([^]]+)\] ]]; then
+		module=${words[$last]}
+		# some traces format is "(%pS)", which like "(foo+0x0/0x1 [bar])"
+		# so $module may like "[bar])". Strip the right parenthesis firstly
+		module=${module%\)}
+		module=${module#\[}
+		module=${module%\]}
+		modbuildid=${module#* }
+		module=${module% *}
+		if [[ $modbuildid == $module ]]; then
+			modbuildid=
+		fi
+		symbol=${words[$last-1]}
+		unset words[$last-1] spaces[$last-1]
+	else
+		# The symbol is the last element, process it
+		symbol=${words[$last]}
+		module=
+		modbuildid=
+	fi
+
+	unset words[$last]
+	parse_symbol # modifies $symbol
+
+	# Add up the line number to the symbol
+	for i in "${!words[@]}"; do
+		echo -n "${spaces[i]}${words[i]}"
+	done
+	echo "${spaces[$last]}${symbol}${module:+ ${module}}${info_str:+ ${info_str}}"
+}
+
+while read line; do
+	# Strip unexpected carriage return at end of line
+	line=${line%$'\r'}
+
+	# Let's see if we have an address in the line
+	if [[ $line =~ \[\<([^]]+)\>\] ]] ||
+	   [[ $line =~ [^+\ ]+\+0x[0-9a-f]+/0x[0-9a-f]+ ]]; then
+		# Translate address to line numbers
+		handle_line "$line"
+	# Is it a code line?
+	elif [[ $line == *Code:* ]]; then
+		decode_code "$line"
+	# Is it a version line?
+	elif [[ -n $debuginfod && $line =~ PID:\ [0-9]+\ Comm: ]]; then
+		debuginfod_get_vmlinux "$line"
+	else
+		# Nothing special in this line, show it as is
+		echo "$line"
+	fi
+done