[PATCH 2/2] ptrace: do not use task_lock() for attach
Roland McGrath
roland at redhat.com
Mon May 4 19:09:35 UTC 2009
This looks good to me overall. It might be worth slicing it into two or
more patches, just for bisect paranoia. (e.g. PF_KTHREAD; task_lock in
ptrace_attach; task_lock in ptrace_traceme.)
I think it merits a comment that the PF_KTHREAD check does not need any
interlock because daemonize() will detach ptrace via reparent_to_kthreadd()
after it sets PF_KTHREAD. (vs the old ->mm check under task_lock.)
It is worth noting that this changes the security_ptrace_traceme() call so
it's no longer under task_lock(). I can't see any way the LSM hooks care,
but it is a change.
You also didn't mention the s/|=/=/ changes. Those are correct, we've
already agreed, but the commit log should mention that this subtle change
was intentional.
Thanks,
Roland
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