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