touch-packages team mailing list archive

[Harry Willis <1337827@xxxxxxxxxxxxxxxxxx>]

So, after some browsing, it apears that trap recursion was introduced
intentionally in 4.3-rc2. There is commented code in bash.c that makes
it look like trap recursion was originally intended to be a configurable
build option, but was made default behaviour instead.

One fairly easy fix would be to use a definable recursion limit within
run_pending_traps, but I suppose we should really get a verdict on
whether the plan is for recursion behaviour to stay as-is or to become a
configurable option.

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https://bugs.launchpad.net/bugs/1337827

Title:
  Bash crashes with a segmentation fault on "trap 'kill 0' SIGTERM EXIT"

Status in “bash” package in Ubuntu:
  Confirmed

Bug description:
  Trusty's bash (4.3-7ubuntu1) crashes with a segmentation fault on the following trap statement:
  trap 'kill 0' SIGTERM EXIT

  Apport doesn't react to this crash and so I wasn't able to submit this
  bug via Apport. :-/


  $ dpkg-query --show --showformat '${Package}\t${Version}\t${Architecture}\n' bash
  bash	4.3-7ubuntu1	amd64

  
  $ cat test.sh 
  #!/bin/bash
  trap 'kill 0' SIGTERM EXIT

  
  $ ./test.sh ; echo $?
  Segmentation fault (core dumped)
  139

  
  $ gdb --args /bin/bash test.sh   (with nostrip and noopt bash build)
  (gdb) bt
  #0  0x00007ffff761e267 in kill () at ../sysdeps/unix/syscall-template.S:81
  #1  0x000000000044fbf2 in kill_pid (pid=0, sig=15, group=0) at .././jobs.c:3158
  #2  0x0000000000494a09 in kill_builtin (list=0x7388a8) at ../.././builtins/../.././builtins/kill.def:186
  #3  0x000000000043c7c0 in execute_builtin (builtin=0x494601 <kill_builtin>, words=0x738908, flags=0, subshell=0) at .././execute_cmd.c:4337
  #4  0x000000000043d3d0 in execute_builtin_or_function (words=0x738908, builtin=0x494601 <kill_builtin>, var=0x0, redirects=0x0, fds_to_close=0x738808, flags=0)
      at .././execute_cmd.c:4758
  #5  0x000000000043c271 in execute_simple_command (simple_command=0x73a0c8, pipe_in=-1, pipe_out=-1, async=0, fds_to_close=0x738808) at .././execute_cmd.c:4161
  #6  0x0000000000435fe1 in execute_command_internal (command=0x73a088, asynchronous=0, pipe_in=-1, pipe_out=-1, fds_to_close=0x738808) at .././execute_cmd.c:787
  #7  0x0000000000490123 in parse_and_execute (string=0x737588 "kill 0", from_file=0x4e275f "exit trap", flags=21) at ../.././builtins/evalstring.c:367
  #8  0x00000000004697ef in run_exit_trap () at .././trap.c:846
  #9  0x000000000041ef9e in exit_shell (s=0) at .././shell.c:915
  #10 0x000000000041eacf in main (argc=2, argv=0x7fffffffdef8, env=0x7fffffffdf10) at .././shell.c:756

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