On Tue, Jul 2, 2024 at 10:36 AM Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > > On Tue, 2 Jul 2024 13:21:36 +0000 Yosry Ahmed <yosryahmed@xxxxxxxxxx> wrote: > > > This series has fixups and cleanups for LAM. Most importantly, patch 1 > > fixes a sycnhronization issue that may cause crashes of userspace > > applications. This is a resend of v3, rebased on top of v6.10-rc6. > > "Crashes of userspace applications" is bad. Yet the patchset has been > floating about for four months. > > It's unclear (to me) how serious this is. Can you please explain how > common this is, what the userspace application needs to do to trigger > this, etc? I don't think it would be common. The bug only happens on new hardware supporting LAM, and it happens in a specific scenario where a userspace task enables LAM while a kthread is using (borrowing) its mm_struct on another CPU. So it is possible but I certainly wouldn't call it common or easily triggerable.
