Hi,
On Tue, Jan 14, 2020 at 5:37 PM Stephen Boyd <swboyd@xxxxxxxxxxxx> wrote:
>
> This tracepoint is hit now that we call into the rpmh code from the cpu
> idle path. Let's move this to be an rcuidle tracepoint so that we avoid
> the RCU idle splat below
>
> =============================
> WARNING: suspicious RCU usage
> 5.4.10 #68 Tainted: G S
> -----------------------------
> drivers/soc/qcom/trace-rpmh.h:72 suspicious rcu_dereference_check() usage!
>
> other info that might help us debug this:
>
> RCU used illegally from idle CPU!
> rcu_scheduler_active = 2, debug_locks = 1
> RCU used illegally from extended quiescent state!
> 5 locks held by swapper/2/0:
> #0: ffffff81745d6ee8 (&(&genpd->slock)->rlock){+.+.}, at: genpd_lock_spin+0x1c/0x2c
> #1: ffffff81745da6e8 (&(&genpd->slock)->rlock/1){....}, at: genpd_lock_nested_spin+0x24/0x34
> #2: ffffff8174f2ca20 (&(&genpd->slock)->rlock/2){....}, at: genpd_lock_nested_spin+0x24/0x34
> #3: ffffff8174f2c300 (&(&drv->client.cache_lock)->rlock){....}, at: rpmh_flush+0x48/0x24c
> #4: ffffff8174f2c150 (&(&tcs->lock)->rlock){+.+.}, at: rpmh_rsc_write_ctrl_data+0x74/0x270
>
> stack backtrace:
> CPU: 2 PID: 0 Comm: swapper/2 Tainted: G S 5.4.10 #68
> 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
> genpd_power_off+0x1e0/0x208
> genpd_power_off+0x1e0/0x208
> genpd_runtime_suspend+0x1ac/0x220
> __rpm_callback+0x70/0xfc
> rpm_callback+0x34/0x8c
> rpm_suspend+0x218/0x4a4
> __pm_runtime_suspend+0x88/0xac
> psci_enter_domain_idle_state+0x3c/0xb4
> cpuidle_enter_state+0xb8/0x284
> cpuidle_enter+0x38/0x4c
> call_cpuidle+0x3c/0x68
> do_idle+0x194/0x260
> cpu_startup_entry+0x24/0x28
> secondary_start_kernel+0x150/0x15c
>
> Fixes: a65a397f2451 ("cpuidle: psci: Add support for PM domains by using genpd")
> Reported-by: Sai Prakash Ranjan <saiprakash.ranjan@xxxxxxxxxxxxxx>
> Cc: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> Signed-off-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>
> ---
>
> I think the commit that this is "Fixes"ing is a stable commit, but I'm
> not positive.
>
> drivers/soc/qcom/rpmh-rsc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
I'm not an expert on these code path, but it looks sane to me.
Reviewed-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
