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However, independent of this warning, can xfpregs_get()->sync_fpstate() be called in the context of the PF_USER_WORKER thread? Would that be problematic? > Damn, I was going to check the ptrace / coredump paths but didn't have > time and then forgot :/ > > For now, I think we need to remove PF_USER_WORKER from x86_task_fpu(). > Then, we add it back later. > Adding PF_USER_WORKER to the warning is only proposed in this patch so no harm done yet. But, I am also skeptical about the x86_task_fpu() warnings. We have "struct fpu *" comparisons that seem to be getting flagged but should be valid in principle. > It is not clear what should we do if debugger does xfpregs_set()... > Yeah, I am wondering whether treating PF_USER_WORKER threads as equivalent to PF_KTHREAD is truly accurate in the FPU.