On Thu, Feb 02, 2023 at 11:50:55AM -1000, Tejun Heo wrote: > On Thu, Feb 02, 2023 at 04:05:14PM -0500, Waiman Long wrote: > > > > On 2/2/23 15:53, Waiman Long wrote: > > > > > > On 2/2/23 15:48, Tejun Heo wrote: > > > > On Thu, Feb 02, 2023 at 03:46:02PM -0500, Waiman Long wrote: > > > > > > > I will work on a patchset to do that as a counter offer. > > > > > > We will need a small and simple patch for /urgent, or I will need to > > > > > > revert all your patches -- your call. > > > > > > > > > > > > I also don't tihnk you fully appreciate the ramifications of > > > > > > task_cpu_possible_mask(), cpuset currently gets that quite wrong. > > > > > OK, I don't realize the urgency of that. If it is that urgent, I > > > > > will have > > > > > no objection to get it in for now. We can improve it later on. > > > > > So are you > > > > > planning to get it into the current 6.2 rc or 6.3? > > > > > > > > > > Tejun, are you OK with that as you are the cgroup maintainer? > > > > Yeah, gotta fix the regression but is there currently a solution > > > > which fixes > > > > the regression but doesn't further break other stuff? > > > > > > I believe there is a better way to do that, but it will need more time > > > to flex out. Since cpuset_cpus_allowed() is only used by > > > kernel/sched/core.c, Peter will be responsible if it somehow breaks > > > other stuff. > > > > Maybe my cpuset patch that don't update task's cpumask on cpu offline event > > can help. However, I don't know the exact scenario where the regression > > happen, so it may not. > > Neither patch looks like they would break anything. That said, the patches > aren't trivial and we're really close to the merge window, so I'd really > appreciate if you can take a look and test a bit before we send these > Linus's way. We can replace it with a better solution afterwards. FWIW, I tested this series in an arm64 heterogeneous setup with things like hotplug and exec()ing between 32-bit and 64-bit tasks and it all seems good. The alternative would be to revert Waiman's setaffinity changes, which I've had a go at here: https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/log/?h=ssa-reverts and I _think_ I've rescued the UAF fix too. What do people prefer? Will
