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[209.85.222.54]) by smtp.gmail.com with ESMTPSA id n189sm5664837vkc.10.2020.01.15.10.19.07 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 15 Jan 2020 10:19:07 -0800 (PST) Received: by mail-ua1-f54.google.com with SMTP id y3so6633502uae.3 for ; Wed, 15 Jan 2020 10:19:07 -0800 (PST) X-Received: by 2002:ab0:5c8:: with SMTP id e66mr15143592uae.120.1579112346977; Wed, 15 Jan 2020 10:19:06 -0800 (PST) MIME-Version: 1.0 References: <20200115013751.249588-1-swboyd@chromium.org> In-Reply-To: <20200115013751.249588-1-swboyd@chromium.org> From: Doug Anderson Date: Wed, 15 Jan 2020 10:18:55 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] drivers: qcom: rpmh-rsc: Use rcuidle tracepoints for rpmh To: Stephen Boyd Cc: Andy Gross , Bjorn Andersson , LKML , linux-arm-msm , Linux PM , Sai Prakash Ranjan , Ulf Hansson Content-Type: text/plain; charset="UTF-8" Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Hi, On Tue, Jan 14, 2020 at 5:37 PM Stephen Boyd 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 > Cc: Ulf Hansson > Signed-off-by: Stephen Boyd > --- > > 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