Hi, On 9/29/2020 2:17 AM, John Stultz wrote:
On Tue, Aug 25, 2020 at 4:22 AM Maulik Shah <[email protected]> wrote:Commit efde2659b0fe ("drivers: qcom: rpmh-rsc: Use rcuidle tracepoints for rpmh") was written to fix a bug seen in an unmerged series that implemented a struct generic_pm_domain::power_off() callback calling rpmh_flush(). See stack trace below.Call trace: dump_backtrace+0x0/0x174 show_stack+0x20/0x2c dump_stack+0xc8/0x124 lockdep_rcu_suspicious+0xe4/0x104 __tcs_buffer_write+0x230/0x2d0 rpmh_rsc_write_ctrl_data+0x210/0x270 rpmh_flush+0x84/0x24c rpmh_domain_power_off+0x78/0x98 _genpd_power_off+0x40/0xc0 genpd_power_off+0x168/0x208 Later the final merged solution is to use CPU PM notification to invoke rpmh_flush() and power_off() callback of genpd is not implemented in the driver. CPU PM notifiers are run with RCU enabled/watching (see cpu_pm_notify() and how it calls rcu_irq_enter_irqson() before calling the notifiers). Remove this change since RCU will not be idle during CPU PM notifications hence not required to use _rcuidle tracepoint. Using _rcuidle tracepoint prevented rpmh driver to be loadable module as these are not exported symbols. This reverts commit efde2659b0fe835732047357b2902cca14f054d9. Cc: Sai Prakash Ranjan <[email protected]> Cc: John Stultz <[email protected]> Cc: Stephen Rothwell <[email protected]> Reviewed-by: Stephen Boyd <[email protected]> Reviewed-by: Sai Prakash Ranjan <[email protected]> Reviewed-by: Ulf Hansson <[email protected]> Signed-off-by: Maulik Shah <[email protected]>Hey Maulik! Thanks so much for sending out this series! I noticed this hasn't made it to -next yet, so would it be good to resubmit it? thanks -john
Sure i will resend the series. Thanks, Maulik -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
