On 2025-11-13 10:51:06 [-0500], Steven Rostedt wrote: > Yes, because they are only tested in sched_switch and fork and exit > tracepoints. > > Although, this was written when tracepoint callbacks were always called > under preempt disable. Perhaps we need to change that call to: > > tracepoint_synchronize_unregister() > > Or add a preempt_disable() around the callers.
Please don't. Please do a regular rcu_read_lock() ;) I tried to get rid of the preempt_disable() around tracepoints so that the attached BPF callbacks are not invoked with disabled preemption. I haven't followed up here in a while but I think Paul's SRCU work goes in the right direction. > I'm very nervous about using RCU here. It will add a lot more corner cases > that needs to be accounted for. The complexity doesn't appear to be worth > it. I'd rather just keep the raw spin locks than to convert it to RCU. > > The seqcount makes sense to me. It's simple and keeps the same paradigm as > what we have. What's wrong with using it? I'm fine with it once you explained under what conditions retry can happen. Thank you. > -- Steve Sebastian
