On Fri, 6 Jul 2018 at 17:22, Kim Phillips <kim.phill...@arm.com> wrote: > > On Thu, 5 Jul 2018 16:13:42 -0600 > Mathieu Poirier <mathieu.poir...@linaro.org> wrote: > > Hi Mathieu, > > > This patch adds the mechanic needed for user space to send PMU specific > ^^^^^^^^ > I think you meant 'mechanism' here: mechanics fix cars :)
I really meant "mechanic", as in "functional details or procedure" [1] [1]. https://www.merriam-webster.com/dictionary/mechanics > > > +static void perf_drv_config_replace(struct perf_event *event, void > > *drv_data) > > +{ > > + unsigned long flags; > > + void *old_drv_data; > > + struct pmu_drv_config *drv_config = &event->hw.drv_config; > > + > > + if (!has_drv_config(event)) > > + return; > > + > > + /* Children take their configuration from their parent */ > > + if (event->parent) > > + return; > > + > > + /* Make sure the PMU doesn't get a handle on the data */ > > + raw_spin_lock_irqsave(&drv_config->lock, flags); > > + > > + old_drv_data = drv_config->config; > > + drv_config->config = drv_data; > > + > > + raw_spin_unlock_irqrestore(&drv_config->lock, flags); > > + > > + /* Free PMU private data allocated by pmu::drv_config_validate() */ > > + event->pmu->drv_config_free(old_drv_data); > > +} > > I got this stacktrace whilst testing a perf tool *without* this series > applied, running on a kernel *with* this series applied: That shouldn't matter as I kept the changes backward compatible specifically to handle this situation. > > [ 132.942054] INFO: trying to register non-static key. > [ 132.946964] the code is fine but needs lockdep annotation. > [ 132.952389] turning off the locking correctness validator. > [ 132.957818] CPU: 2 PID: 2835 Comm: perf64-sans Not tainted > 4.18.0-rc3-00196-g5b5d957532a8-dirty #146 > [ 132.966856] Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno > Development Platform, BIOS EDK II Jan 23 2017 > [ 132.977527] Call trace: > [ 132.979947] dump_backtrace+0x0/0x1c0 > [ 132.983567] show_stack+0x24/0x30 > [ 132.986845] dump_stack+0x90/0xb4 > [ 132.990122] register_lock_class+0x57c/0x580 > [ 132.994343] __lock_acquire.isra.12+0x6c/0x980 > [ 132.998736] lock_acquire+0x100/0x1e8 > [ 133.002357] _raw_spin_lock_irqsave+0x58/0x78 > [ 133.006667] perf_drv_config_replace+0x4c/0x80 > [ 133.011061] _free_event+0xbc/0x460 > [ 133.014507] put_event+0x2c/0x38 > [ 133.017697] perf_event_release_kernel+0x1ac/0x300 > [ 133.022434] perf_release+0x10/0x20 > [ 133.025883] __fput+0xa8/0x1e0 > [ 133.028901] ____fput+0x20/0x30 > [ 133.032006] task_work_run+0xa0/0xd0 > [ 133.035539] do_notify_resume+0x118/0x120 > [ 133.039503] work_pending+0x8/0x10 > > Is a raw_spin_lock_init missing perhaps? Not that I can tell - I need to investigate. > > Thanks, > > Kim
