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It needs two more things: the execve() fails, and the task is >> moved to another CPU during that execve(). > > That has been reported already privately to me and a few others and the > reporter provided a similar patch as you. > > While both variants seem simpler, I prefer the explicit > re-initialization for the failed exec() case. > > It's a NOOP for newly initialized MMs and avoids the pointless fixup > dance for the last user in the common case. I integrated your approach, tested it and wrote a commit message for it. My reproducer passes with it, and so do my other mm_cid tests, on guests with 2 to 64 CPUs. Do you want to take care of it yourself, or should I route it through an mm_cid fixes series I am preparing? If you want me to pick it up, I need your Signed-off-by. The series has four other fixes of mine, selftests for them, and Weiming Shi's teardown fix. One of those four was found by a Spin model of the per task / per CPU state machine. I then confirmed it on a real kernel, with delays inserted by hand in the window. The model is not part of the series. I can send it if you want to look at it. Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. https://www.efficios.com