Hi. I see this discussion somewhat faded away since the previous year.
There was rework [1] that reduced (ab)use of mmap_sem in prctl functions. Actually, there still remains the down_write() in prctl_set_mm. I considered at least replacing it with the mm_struct.arg_lock + down_read() but then I learnt about this thread intending to remove that part completely. I wouldn't oppose if CRIU is the sole (aware) user. Ad the bot build issue, I could build the kernel both with CONFIG_CHECKPOINT_RESTORE and without CONFIG_CHECKPOINT_RESTORE just fine after applying the two proposed patches. What is the current state? Perhaps, this change should be CCed to linux-...@vger.kernel.org(?). Thanks, Michal [1] https://lore.kernel.org/lkml/1523730291-109696-1-git-send-email-yang....@linux.alibaba.com/T/
