RE: [RFC][PATCH 3/7] kprobes: Remove kretprobe hash

From: Eddy_Wu@xxxxxxxxxxxxxx
Date: Fri Aug 28 2020 - 10:11:49 EST


> From: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
>
> OK, schedule function will be the key. I guess the senario is..
>
> 1) kretporbe replace the return address with kretprobe_trampoline on task1's kernel stack
> 2) the task1 forks task2 before returning to the kretprobe_trampoline
> 3) while copying the process with the kernel stack, task2->kretprobe_instances.first = NULL

I think new process created by fork/clone uses a brand new kernel stack? I thought only user stack are copied.
Otherwise any process launch should crash in the same way

By the way, I can reproduce this on the latest branch(v4)
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