Messages in this thread | | | Date | Wed, 27 Jul 2011 18:31:59 +0200 | From | Oleg Nesterov <> | Subject | [PATCH 0/8] make vfork killable/restartable/traceable |
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Hello.
CLONE_VFORK sleeps in TASK_INTERRUPTIBLE until the child exits/execs. This is obviously not good, it is sooo simple to create the task which doesn't react to SIGKILL/SIGSTOP.
Questions:
- do we really need this?
I think we do. This really "looks like a bug" in any case, even if nobody ever complained afaik.
- may be 1-3 is enough?
may be... but personally I think SIGSTOP/ptrace should work too.
- is it safe to exit/stop on !x86 machine???
I do not know. May be this needs some #ifdef's around wait_for_completion_interruptible(). I am not sure that, say, arch_ptrace_stop() can't abuse the ->mm shared with the child.
OTOH. This can happen anyway, do_fork() does ptrace_event() before wait_for_completion().
- and of course, while I think this is bugfix, this is user visible change.
Please comment.
9/8 is off-topic.
Oleg.
fs/exec.c | 11 ---- include/linux/sched.h | 2 +- include/linux/thread_info.h | 4 ++ kernel/fork.c | 121 ++++++++++++++++++++++++++++++++++--------- kernel/pid.c | 13 +++++ 5 files changed, 114 insertions(+), 37 deletions(-)
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