Review request for 5049299 (original) (raw)

Roland McGrath roland at redhat.com
Wed Jul 1 00:10:56 UTC 2009

You write "It's all the same "clone" code in the kernel." and that may be true, but I'm thinking about the glibc wrappers around them.

I only made that point in response to your contrasts between "a dedicated vfork syscall number" and "a clone call passed CLONE_VFORK | CLONE_VM | SIGCHLD", for which the kernel's semantics are completely identical.

In particular, it seems to me that vfork and clone(CLONEVM|CLONEVFORK) should have similar assembly wrappers around them. But the vfork code uses SAVEPID/RESTOREPID which frobs only the pid, not the tid, while clone used RESETPID which frobs both the pid and tid. It seems to me they should share common infrastructure.

That makes sense to me, but I have not looked closely at that logic.

Thanks, Roland

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