scripts/decode_stacktrace.sh

   1 #!/bin/bash
   2 # (c) 2014, Sasha Levin <sasha.levin@oracle.com>
   3 #set -x
   4
   5 if [[ $# < 2 ]]; then
   6         echo "Usage:"
   7         echo "  $0 [vmlinux] [base path] [modules path]"
   8         exit 1
   9 fi
  10
  11 vmlinux=$1
  12 basepath=$2
  13 modpath=$3
  14 declare -A cache
  15 declare -A modcache
  16
  17 parse_symbol() {
  18         # The structure of symbol at this point is:
  19         #   ([name]+[offset]/[total length])
  20         #
  21         # For example:
  22         #   do_basic_setup+0x9c/0xbf
  23
  24         if [[ $module == "" ]] ; then
  25                 local objfile=$vmlinux
  26         elif [[ "${modcache[$module]+isset}" == "isset" ]]; then
  27                 local objfile=${modcache[$module]}
  28         else
  29                 [[ $modpath == "" ]] && return
  30                 local objfile=$(find "$modpath" -name $module.ko -print -quit)
  31                 [[ $objfile == "" ]] && return
  32                 modcache[$module]=$objfile
  33         fi
  34
  35         # Remove the englobing parenthesis
  36         symbol=${symbol#\(}
  37         symbol=${symbol%\)}
  38
  39         # Strip the symbol name so that we could look it up
  40         local name=${symbol%+*}
  41
  42         # Use 'nm vmlinux' to figure out the base address of said symbol.
  43         # It's actually faster to call it every time than to load it
  44         # all into bash.
  45         if [[ "${cache[$module,$name]+isset}" == "isset" ]]; then
  46                 local base_addr=${cache[$module,$name]}
  47         else
  48                 local base_addr=$(nm "$objfile" | grep -i ' t ' | awk "/ $name\$/ {print \$1}" | head -n1)
  49                 cache[$module,$name]="$base_addr"
  50         fi
  51         # Let's start doing the math to get the exact address into the
  52         # symbol. First, strip out the symbol total length.
  53         local expr=${symbol%/*}
  54
  55         # Now, replace the symbol name with the base address we found
  56         # before.
  57         expr=${expr/$name/0x$base_addr}
  58
  59         # Evaluate it to find the actual address
  60         expr=$((expr))
  61         local address=$(printf "%x\n" "$expr")
  62
  63         # Pass it to addr2line to get filename and line number
  64         # Could get more than one result
  65         if [[ "${cache[$module,$address]+isset}" == "isset" ]]; then
  66                 local code=${cache[$module,$address]}
  67         else
  68                 local code=$(addr2line -i -e "$objfile" "$address")
  69                 cache[$module,$address]=$code
  70         fi
  71
  72         # addr2line doesn't return a proper error code if it fails, so
  73         # we detect it using the value it prints so that we could preserve
  74         # the offset/size into the function and bail out
  75         if [[ $code == "??:0" ]]; then
  76                 return
  77         fi
  78
  79         # Strip out the base of the path
  80         code=${code//$basepath/""}
  81
  82         # In the case of inlines, move everything to same line
  83         code=${code//$'\n'/' '}
  84
  85         # Replace old address with pretty line numbers
  86         symbol="$name ($code)"
  87 }
  88
  89 decode_code() {
  90         local scripts=`dirname "${BASH_SOURCE[0]}"`
  91
  92         echo "$1" | $scripts/decodecode
  93 }
  94
  95 handle_line() {
  96         local words
  97
  98         # Tokenize
  99         read -a words <<<"$1"
 100
 101         # Remove hex numbers. Do it ourselves until it happens in the
 102         # kernel
 103
 104         # We need to know the index of the last element before we
 105         # remove elements because arrays are sparse
 106         local last=$(( ${#words[@]} - 1 ))
 107
 108         for i in "${!words[@]}"; do
 109                 # Remove the address
 110                 if [[ ${words[$i]} =~ \[\<([^]]+)\>\] ]]; then
 111                         unset words[$i]
 112                 fi
 113
 114                 # Format timestamps with tabs
 115                 if [[ ${words[$i]} == \[ && ${words[$i+1]} == *\] ]]; then
 116                         unset words[$i]
 117                         words[$i+1]=$(printf "[%13s\n" "${words[$i+1]}")
 118                 fi
 119         done
 120
 121         if [[ ${words[$last]} =~ \[([^]]+)\] ]]; then
 122                 module=${words[$last]}
 123                 module=${module#\[}
 124                 module=${module%\]}
 125                 symbol=${words[$last-1]}
 126                 unset words[$last-1]
 127         else
 128                 # The symbol is the last element, process it
 129                 symbol=${words[$last]}
 130                 module=
 131         fi
 132
 133         unset words[$last]
 134         parse_symbol # modifies $symbol
 135
 136         # Add up the line number to the symbol
 137         echo "${words[@]}" "$symbol $module"
 138 }
 139
 140 while read line; do
 141         # Let's see if we have an address in the line
 142         if [[ $line =~ \[\<([^]]+)\>\]  ]]; then
 143                 # Translate address to line numbers
 144                 handle_line "$line"
 145         # Is it a code line?
 146         elif [[ $line == *Code:* ]]; then
 147                 decode_code "$line"
 148         else
 149                 # Nothing special in this line, show it as is
 150                 echo "$line"
 151         fi
 152 done