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