strace woes

Miklos Szeredi miklos at
Wed Jun 13 19:23:16 UTC 2007

When stracing an app that does lots of forks and thread creations, I
get messages like this:

  upeek: ptrace(PTRACE_PEEKUSER,12375,80,0): No such process
  upeek: ptrace(PTRACE_PEEKUSER,15243,80,0): No such process
  upeek: ptrace(PTRACE_PEEKUSER,15729,80,0): No such process
  [preattached child 17146 of 7677 in weird state!]
  PANIC: TCB already set in pid 17146
  upeek: ptrace(PTRACE_PEEKUSER,19158,120,0): No such process
  upeek: ptrace(PTRACE_PEEKUSER,22836,80,0): No such process
  [preattached child 28364 of 28363 in weird state!]
  upeek: ptrace(PTRACE_PEEKUSER,29450,80,0): No such process
  upeek: ptrace(PTRACE_PEEKUSER,29474,80,0): No such process
  upeek: ptrace(PTRACE_PEEKUSER,360,80,0): No such process
  upeek: ptrace(PTRACE_PEEKUSER,3499,136,0): No such process
  upeek: ptrace(PTRACE_PEEKUSER,4764,136,0): No such process

They seem harmless, however sometimes I get this:

  trace: ptrace(PTRACE_SYSCALL, ...): No such process

Which is fatal, the whole thing hangs, and only kill -9 helps.

With the CVS version of strace the difference is that it doesn't hang,
but dies (sometimes only strace itself dies, while the app goes on,
other times both die).

With the CVS version I also noticed that this program can't be killed
with Ctrl-C any more.  Is that a known regression?

Let me know if you need more info.


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