On Tue, 08 Dec 2020 11:35:57 +0100, John Wood said: > I think the stats pointer present in the task_struct's security blob > needs to be protected against concurrency for the following reasons. > > 1.- The same process forking at the same time in two different CPUs. > 2.- The same process execve() at the same time in two different CPUs.
OK, I'll bite. How would these two cases even happen? (Note that you could conceivably issue the fork()/exeve() on one CPU, run kernel code for a bit and then get rescheduled onto a different CPU to complete the syscall, but that's a different cache coherency can-o-worms :) (Your case 3 of a fork/exec while you traverse is an actual issue. Note that you missed one case - where the process evaporates for some reason while you do the traverse and you're left with a stale pointer...)
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