Re: [Uclinux-dist-devel] [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage of child->mm

From: Mike Frysinger
Date: Mon May 24 2010 - 00:34:10 EST


On Sat, May 22, 2010 at 12:54, Oleg Nesterov wrote:
> Now that Mike Frysinger unified the FDPIC ptrace code, we can fix
> the unsafe usage of child->mm in ptrace_request(PTRACE_GETFDPIC).
>
> We have the reference to task_struct, and ptrace_check_attach()
> verified the tracee is stopped. But nothing can protect from
> SIGKILL after that, we must not assume child->mm != NULL.

gdb still works with FDPIC apps after this, so presumably it works
fine :). ive added it to the Blackfin tree to get more testing on our
side (not that i'll be pushing it out or anything).

thanks!
-mike
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